1 Why “Just Follow the ASTM Standard” Is Harder Than It Sounds
A colleague tells you to “run an ASTM corrosion test” on a new alloy, and you go looking for the standard. What you find is not one standard but a sprawling family spanning the active ASTM G01.11 electrochemical corrosion standards — G3, G5, G59, G61, G69, G71, G82, G96, G100, G102, G106, G108, G148, G150, G189, G192, G199, G215, G217 and G220 — together with selected corrosion-related standards outside G01.11, such as G185 for rotating-cylinder-electrode inhibitor screening, F2129 and F746 for medical-device corrosion, and B825 for surface-film characterisation. Several of them reference each other. None of them, read in isolation, tells you which cell geometry, reference electrode, specimen configuration or potentiostat mode you actually need on the bench.
This is the gap this guide closes. Major electrochemical instrument suppliers each publish their own mapping of these standards to specific techniques and hardware, and that body of technical literature is the benchmark against which the standards coverage below has been checked. Rather than treating each standard as an isolated document, this guide organises the ASTM electrochemical corrosion family by what you are actually trying to measure — a foundational convention, a polarisation behaviour, a localised corrosion susceptibility, a galvanic interaction, a surface film, or an impedance spectrum — and tells you which ScienceGears corrosion cell configuration and potentiostat mode are appropriate for running it.
This guide is structured around the active ASTM G01.11 electrochemical corrosion standards, with additional coverage of selected ASTM F-series medical-device standards and B-series surface-film standards that are commonly referenced by major electrochemical corrosion-instrument suppliers. Related non-electrochemical corrosion standards, such as salt spray, coating exposure and weathering tests, are outside the main scope unless they are useful for context or comparison.
2 The Foundational Standards — Read These Before Any Test Method
Three ASTM documents in this section are not corrosion test methods on unknown materials; they are conventions, calculation frameworks and verification practices that other electrochemical corrosion standards assume you understand. Omitting these steps is the commonest reason researchers draw incorrect conclusions from their data.
2.1 ASTM G3 — Conventions for Electrochemical Corrosion Measurements
ASTM G3, Standard Practice for Conventions Applicable to Electrochemical Measurements in Corrosion Testing, defines the sign conventions, terminology, and plotting conventions used throughout the rest of the G-series. It specifies, for example, whether anodic current is plotted as positive or negative, how potential is referenced, and how to label a polarisation curve consistently with the rest of the literature. Published corrosion testing application notes routinely transform raw voltammogram data according to G3 conventions before presenting the final potential-versus-log-current-density plot, which is the standard format expected in the corrosion literature.
If you have ever compared two published polarisation curves and found the anodic and cathodic branches apparently reversed relative to each other, the underlying cause is very often an inconsistent application of G3 conventions rather than a real difference in corrosion behaviour.
2.2 ASTM G102 — Calculating Corrosion Rates from Electrochemical Data
ASTM G102, Standard Practice for Calculation of Corrosion Rates and Related Information from Electrochemical Measurements, provides the calculation framework for converting electrochemical measurements, such as corrosion current density or polarisation-resistance-derived values, into an estimated uniform corrosion rate, typically expressed in millimetres per year or mils per year. It specifies the Faraday’s Law-based calculation, the equivalent weight determination for alloys (rather than pure metals), and the density correction required to convert a current density into a penetration rate. Researchers quoting corrosion rates in mm/year from Tafel or LPR data must follow ASTM G102 and calculate equivalent weight correctly; using the wrong value for multi-element alloys can inflate or deflate rates by two-fold or more.
2.3 ASTM G106 — Verifying Your Instrument and Algorithm Before Trusting EIS Data
ASTM G106, Standard Practice for Verification of Algorithm and Equipment for Electrochemical Impedance Measurements, provides a procedure for checking the instrumentation, technique and data-presentation workflow used for EIS measurements. It should be treated as an EIS verification practice rather than a corrosion test on an unknown sample. Dummy-cell checks can be useful, but G106 is broader than a simple resistor-capacitor dummy-cell test because it verifies whether the instrument, cabling, measurement procedure and analysis workflow can reproduce expected EIS behaviour before real corrosion data are trusted.
3 Polarisation Methods — The Core Technique Family
Polarisation methods make up the largest and most frequently used group of ASTM electrochemical corrosion standards. They all share the same basic principle — sweeping or holding an applied potential and measuring the resulting current — but differ in scan range, scan rate, target alloy class, and what failure mode they are designed to reveal.
3.1 ASTM G5 — Potentiodynamic Anodic Polarisation Measurements
ASTM G5, Standard Reference Test Method for Making Potentiodynamic Anodic Polarization Measurements, is primarily a reference method for checking experimental technique and instrumentation under defined conditions. When followed using the specified reference material and procedure, it allows laboratories to compare whether their electrochemical setup can reproduce expected potentiodynamic anodic polarisation behaviour. G5-style wide anodic polarisation scans are also useful for general corrosion characterisation, but modified studies should be described as G5-style or G5-aligned rather than strict ASTM G5 reference testing unless the standard procedure is followed.
3.2 ASTM G59 — Potentiodynamic Polarisation Resistance Measurements (LPR)
ASTM G59, Standard Test Method for Conducting Potentiodynamic Polarization Resistance Measurements, is the linear polarisation resistance (LPR) method — a small-amplitude potential sweep around the open-circuit corrosion potential, typically ±10–20 mV, used to determine the polarisation resistance (Rp) without driving the specimen far into its active or passive regions. Rp is then converted to a corrosion rate using the Stern-Geary relationship and the calculation procedure specified in ASTM G102. LPR (G59) is widely classified alongside electrochemical noise (G199) as one of the two principal techniques for investigating uniform corrosion.
LPR is the method of choice when you need a fast, minimally destructive corrosion rate estimate — the small potential excursion means the specimen surface is not significantly altered by the measurement, making LPR suitable for repeated monitoring of the same specimen over time.
3.3 ASTM G61 — Cyclic Potentiodynamic Polarisation for Localised Corrosion Susceptibility
ASTM G61, Standard Test Method for Conducting Cyclic Potentiodynamic Polarization Measurements for Localized Corrosion Susceptibility of Iron-, Nickel-, or Cobalt-Based Alloys, extends the basic potentiodynamic scan into a forward-and-reverse cycle. The potential is swept anodically until a defined current density threshold is reached (typically indicating breakdown of the passive film), then reversed back toward the starting potential. The presence and size of a hysteresis loop between the forward and reverse scans — and the potential at which the reverse scan re-crosses the forward scan — is the primary diagnostic for susceptibility to pitting corrosion. ASTM G61 is widely used as a standardised method to test the susceptibility of iron, nickel, and cobalt alloys to localised corrosion within a chloride environment, with the corrosion potential, pitting potential, and passivity range all extracted directly from the cyclic voltammogram.
ASTM G61 is commonly run in a chloride electrolyte; many G61-aligned application examples use 3.5% NaCl at room temperature to represent an aggressive chloride environment. Confirm the exact electrolyte, temperature, deaeration and scan conditions against the current standard and the material/application being tested. Other electrolytes — sulphuric acid, hydrochloric acid, sodium hydroxide — may be specified for applications targeting other service environments, but 3.5% NaCl is the default reference condition most published G61 data is benchmarked against.
3.4 ASTM G100 — Cyclic Galvanostaircase Polarisation
ASTM G100, Standard Test Method for Conducting Cyclic Galvanostaircase Polarization, is a specialised electrochemical method for assessing relative susceptibility to localised corrosion using cyclic galvanostaircase polarisation. Unlike G61, which uses a continuous potential sweep, G100 applies a staircase of increasing and then decreasing current steps under galvanostatic control and records the resulting potential response. The standard was developed around aluminium alloy 3003-H14 and may also serve as a guide for examining other alloys, so it should not be presented as a direct iron-, nickel- and cobalt-alloy equivalent to G61.
4 Localised Corrosion and Repassivation Methods
This section covers a family of standards specifically targeting pitting, crevice, and intergranular corrosion susceptibility — failure modes that general polarisation scans such as G5 do not reliably reveal, since localised corrosion initiates at discrete sites rather than uniformly across the exposed surface.
4.1 ASTM G150 — Electrochemical Critical Pitting Temperature Testing
ASTM G150, Standard Test Method for Electrochemical Critical Pitting Temperature Testing of Stainless Steels and Related Alloys, evaluates resistance to stable propagating pitting corrosion by determining the critical pitting temperature (CPT) under defined electrochemical conditions. Rather than holding temperature constant and sweeping potential, G150 applies a defined anodic potential while temperature is increased under controlled conditions. CPT is identified from the specified current-response criterion, followed by specimen examination to confirm the corrosion mode.
4.2 ASTM G192 — Crevice Repassivation Potential
ASTM G192, Standard Test Method for Determining the Crevice Repassivation Potential of Corrosion-Resistant Alloys Using a Potentiodynamic-Galvanostatic-Potentiostatic Technique, addresses crevice corrosion specifically — a localised attack mode that initiates within tight geometric crevices (such as gasket interfaces, washer contacts, or threaded joints) where restricted electrolyte exchange creates locally aggressive conditions distinct from the bulk environment. The standard’s three-stage technique name reflects its structure: an initial potentiodynamic scan, a galvanostatic hold to drive crevice initiation, and a final potentiostatic step-down to determine the repassivation potential — the potential below which an initiated crevice will heal rather than propagate. This is a more rigorous and more specific test than the localised corrosion susceptibility captured by G61, and corrosion training curricula explicitly distinguish crevice corrosion (G192) as a separate evaluation target from the broader localised corrosion category covered by G61 and G100.
4.3 ASTM G108 — Electrochemical Reactivation (EPR) for Sensitisation Detection
ASTM G108, Standard Test Methods for Electrochemical Reactivation (EPR) for Detecting Sensitization of AISI Type 304 and 304L Stainless Steels, is a specialised technique distinct from the pitting- and crevice-focused standards above. Sensitisation refers to chromium carbide precipitation at grain boundaries — typically caused by improper heat treatment or welding — which depletes chromium locally and leaves the grain boundary region susceptible to intergranular corrosion even though the bulk alloy composition remains nominally corrosion-resistant.
EPR detects this by anodically polarising the specimen to passivate it fully, then reactivating it with a reverse (cathodic-direction) scan; the charge passed during reactivation correlates with the degree of sensitisation, since chromium-depleted grain boundary regions reactivate more readily than well-passivated, chromium-rich bulk material. G108 is applicable specifically to AISI 304 and 304L stainless steels.
5 Galvanic, Sensitisation, and Surface Film Methods
5.1 ASTM G71 — Conducting and Evaluating Galvanic Corrosion Tests
ASTM G71, Standard Guide for Conducting and Evaluating Galvanic Corrosion Tests in Electrolytes, addresses galvanic corrosion between two dissimilar metals in electrical contact in a shared electrolyte. It is a broader guide covering test design, specimen selection, area ratio, exposure environment and evaluation, not only a potentiostat-based ZRA measurement. Where galvanic current is measured electrochemically, a zero-resistance ammeter or suitable galvanic-current monitoring mode may be used, but exposure geometry and material pairing remain central to the test.
For galvanic-current and ZRA-capable configurations, contact ScienceGears for Corrosion-capable potentiostat.
5.2 ASTM B825 — Coulometric Reduction of Surface Films
ASTM B825, Standard Test Method for Coulometric Reduction of Surface Films on Metallic Test Samples, occupies a distinct position from the corrosion-rate and susceptibility standards above. It covers procedures for determining the relative buildup of corrosion and tarnish films, including oxides, on metal surfaces by the constant-current coulometric technique — also called the cathodic reduction method. Rather than measuring an active corrosion rate or susceptibility to a specific failure mode, B825 is a film characterisation technique: a constant cathodic current is applied to a specimen bearing a pre-existing corrosion or tarnish film, and the time taken to electrochemically reduce that film back to bare metal is used to calculate the film’s relative thickness or charge density.
The standard is designed primarily to evaluate control coupons that have undergone separate gaseous environmental exposure testing — particularly for components containing electrical contacts — and has been demonstrated to be most reliably applicable to copper and silver specimens, with other metals requiring further validation before B825 is applied to them. Major instrument suppliers include B825 within their corrosion-relevant standards lists because the constant-current coulometric technique is run on the same potentiostat/galvanostat platform used for the other methods in this guide, even though its measurement objective — quantifying an existing film rather than measuring active corrosion behaviour — differs from G5, G59, or G61.
For constant-current coulometric reduction and general electrochemical cell setups, see General electrochemical cells.
6 Electrochemical Noise, Monitoring and Specialised Methods
6.1 ASTM G199 — Electrochemical Noise Measurement
ASTM G199, Standard Guide for Electrochemical Noise Measurement, provides a means for electrochemical testing for corrosion based on monitoring the spontaneous, naturally occurring fluctuations in potential and current at a freely corroding specimen — without applying any external potential or current perturbation. According to the ASTM subcommittee member who led its development, the guide details the procedure for making electrochemical noise measurements for the detection of both general and localised corrosion, and provides several methods for analysing the resulting noise data, an area that has historically lacked a single consolidated reference despite electrochemical noise being studied for almost three decades prior to G199’s publication. Because electrochemical noise requires no applied perturbation, it is particularly well suited to monitoring corrosion in service or in systems where applying a polarising signal is undesirable, though it is primarily a laboratory-oriented technique.
6.2 ASTM G185 — Evaluating Corrosion Inhibitors Using the Rotating Cylinder Electrode
ASTM G185, Standard Practice for Evaluating and Qualifying Oil Field and Refinery Corrosion Inhibitors Using the Rotating Cylinder Electrode, addresses a specific and industrially important application: screening chemical corrosion inhibitors under controlled hydrodynamic conditions relevant to oil and gas production and refining environments. The rotating cylinder electrode (RCE) creates a defined, reproducible turbulent flow regime at the specimen surface — relevant because inhibitor performance can depend strongly on flow-induced mass transport and shear, which a static cell cannot replicate. A published application note using an RCE with a carbon steel specimen under ASTM G185 conditions demonstrates linear polarisation and Tafel measurements taken with and without inhibitor present, from which the corrosion rate reduction afforded by the inhibitor is calculated.
Equipment Mapping: G185 requires a dedicated rotating cylinder electrode assembly and a compatible cell rather than a standard static flat-coupon cell — this is specialised hardware outside ScienceGears’ standard flat and jacketed corrosion cell range. Contact the ScienceGears technical team to discuss RCE-compatible cell configurations if your research programme requires G185-aligned inhibitor screening.
6.3 ASTM G148 — Hydrogen Uptake, Permeation, and Transport by Electrochemical Technique
ASTM G148, Standard Practice for Evaluation of Hydrogen Uptake, Permeation, and Transport in Metals by an Electrochemical Technique, addresses a corrosion-adjacent but mechanistically distinct phenomenon: hydrogen embrittlement. The practice uses a two-compartment electrochemical permeation cell, typically following the Devanathan-Stachurski configuration, in which hydrogen is electrochemically generated on one face of a thin metal membrane specimen (the charging side) whilst the opposite face (the detection side) is held at an oxidising potential that immediately re-oxidises any hydrogen atoms that have diffused through the metal. The resulting oxidation current as a function of time gives the hydrogen permeation rate and, from the transient shape, the apparent hydrogen diffusivity through the metal — both critical parameters for assessing a material’s susceptibility to hydrogen-induced cracking in sour service or cathodic protection environments.
Equipment Mapping: This requires a dedicated dual-compartment permeation cell with the thin-membrane specimen mounted as the dividing wall between charging and detection compartments — a fundamentally different cell architecture from the flat-coupon corrosion cells used for G5, G59, and G61. This is specialised hardware; contact the ScienceGears technical team to discuss permeation cell configuration for hydrogen uptake studies.
For custom dual-compartment and membrane-separated electrochemical cells, see Custom electrochemical cells.
6.4 Other Active ASTM G01.11 Electrochemical Corrosion Standards
The standards above cover the methods most commonly highlighted in supplier corrosion-testing literature, but ASTM Subcommittee G01.11 also maintains several additional active electrochemical corrosion standards that complete the ASTM electrochemical corrosion map. These are usually more specialised than G5, G59, G61, G102, G106, G150 or G192, but they are important for aluminium alloys, galvanic-series development, plant corrosion monitoring, corrosion under insulation, electrode-potential measurement, multielectrode-array monitoring and reference-electrode replacement.
ASTM G69 — Corrosion Potentials of Aluminium Alloys
ASTM G69 covers measurement of corrosion potentials of aluminium alloys. Unlike G5, G59 or G61, it is not primarily a polarisation scan; its focus is the measurement of corrosion potential under defined conditions. This is useful when comparing aluminium alloys, heat treatments or surface conditions where the open-circuit/corrosion potential gives an important indication of relative electrochemical behaviour.
Equipment mapping: A standard electrochemical cell or corrosion cell with an aluminium working specimen and a stable reference electrode is appropriate. The key instrument requirement is stable high-impedance potential measurement or open-circuit potential monitoring rather than a high-current polarisation capability.
ASTM G82 — Development and Use of Galvanic Series
ASTM G82 is a guide for developing and using a galvanic series to predict galvanic corrosion performance. It supports the interpretation of galvanic compatibility between dissimilar metals and should be read alongside ASTM G71 when galvanic corrosion is the concern. Unlike G71, which guides galvanic corrosion testing of coupled metals, G82 focuses on ranking materials according to their corrosion potentials in a defined environment.
Equipment mapping: A corrosion cell or immersion setup with stable reference-electrode measurement is required. The main requirement is reproducible corrosion-potential measurement for each material in the same electrolyte and under the same exposure conditions.
ASTM G96 — Online Corrosion Monitoring in Plant Equipment
ASTM G96 is a guide for online monitoring of corrosion in plant equipment using electrical and electrochemical methods. This is more relevant to industrial process plants, pipelines, refineries and continuous monitoring applications than to a single benchtop coupon test. Depending on the monitoring approach, the method may involve electrochemical probes, electrical resistance probes, linear polarisation resistance, galvanic monitoring or related sensor-based corrosion measurements.
Equipment mapping: G96 is usually associated with field or plant monitoring probes rather than a standard laboratory glass corrosion cell. For laboratory simulation or training, the closest equivalent would be a corrosion-monitoring setup using suitable probes, stable reference electrodes, low-noise measurement electronics and software for long-term data logging.
ASTM G189 — Laboratory Simulation of Corrosion Under Insulation
ASTM G189 covers laboratory simulation of corrosion under insulation. Corrosion under insulation is a practical industrial failure mode where trapped moisture, salts, oxygen and thermal cycling can create aggressive local conditions beneath insulation. Although this standard is not a routine three-electrode polarisation method like G5, G59 or G61, it belongs in the wider ASTM G01.11 electrochemical corrosion family because corrosion monitoring and electrochemical measurement may be used to follow the corrosion process under simulated insulation conditions.
Equipment mapping: G189 normally requires a corrosion-under-insulation simulation fixture rather than a standard flat corrosion cell. If electrochemical monitoring is included, the setup may require embedded electrodes, reference-electrode access, temperature control, wet/dry cycling and long-term monitoring capability.
ASTM G215 — Electrode Potential Measurement
ASTM G215 is a guide for electrode potential measurement. This is highly relevant to almost every electrochemical corrosion method because errors in reference-electrode selection, placement, conversion or reporting can lead to incorrect interpretation of corrosion potential, pitting potential, repassivation potential or polarisation curves. G215 is therefore best treated as a practical measurement-quality guide that supports G5, G59, G61, G69, G71, G150, G192 and other potential-based corrosion methods.
Equipment mapping: The key requirements are a stable reference electrode, correct reference-electrode placement, a high-impedance voltmeter or potentiostat input, and clear reporting of the reference scale used. This is not a separate corrosion cell type, but it is essential for reliable corrosion measurements.
ASTM G217 — Coupled Multielectrode Array Sensor Corrosion Monitoring
ASTM G217 covers corrosion monitoring in laboratories and plants using the coupled multielectrode array sensor method. This approach uses an array of small, electrically coupled electrode elements to detect non-uniform corrosion activity, making it useful for monitoring localised corrosion tendencies and corrosion distribution over time. It is more specialised than conventional LPR or cyclic polarisation, but it is important where spatially distributed corrosion information is required.
Equipment mapping: G217 requires a coupled multielectrode array sensor or probe, together with suitable low-current measurement electronics and data acquisition. It is not normally run in a standard single-coupon flat corrosion cell unless the cell is specifically adapted to house the multielectrode-array sensor.
ASTM G220 — Replacing Saturated Calomel Reference Electrodes
ASTM G220 provides guidance for replacing saturated calomel reference electrodes (SCE) when measuring electrode potentials. This is practically important because SCE contains mercury and many laboratories prefer or require alternative reference electrodes such as Ag/AgCl or other reference systems. When replacing SCE, the reference scale must be clearly converted and reported so that corrosion potentials, pitting potentials and repassivation potentials remain comparable.
Equipment mapping: No special corrosion cell is required. The important requirement is correct reference-electrode selection, maintenance, calibration/checking and potential conversion when comparing results reported against different reference electrodes.
7 Medical Implant Corrosion Standards (F-Series)
This is a separate ASTM committee jurisdiction (F04, Medical and Surgical Materials and Devices) from the G01 corrosion-of-metals committee, but the two F-series standards below are explicitly electrochemical polarisation techniques and are commonly grouped alongside G61 in supplier corrosion technique catalogues because they share the same cyclic potentiodynamic polarisation principle, applied to a different class of specimen.
7.1 ASTM F2129 — Cyclic Potentiodynamic Polarisation for Small Implant Devices
ASTM F2129, Standard Test Method for Conducting Cyclic Potentiodynamic Polarization Measurements to Determine the Corrosion Susceptibility of Small Implant Devices, assesses the corrosion susceptibility of small metallic implant medical devices — or components thereof — using cyclic forward-and-reverse potentiodynamic polarisation, conceptually similar in technique to G61 but applied to whole devices in their final form and finish rather than flat coupon material samples. Device types covered include vascular and ureteral stents, filters, endovascular graft support segments, cardiac occluders, aneurysm or ligation clips, and surgical staples. Because corrosion of implantable medical devices can release corrosion products with harmful biological consequences in addition to compromising mechanical performance, the standard is specifically designed to evaluate both general corrosion behaviour and susceptibility to localised corrosion using a realistic simulated physiological electrolyte — artificial physiological electrolytes such as phosphate buffered saline (PBS) are commonly used, with the final electrolyte selected according to the current standard, device type and intended application. A typical F2129 setup may use a multiport electrochemical cell with access for the reference, counter and working/sample electrodes, together with temperature control and gas handling where required by the protocol — a configuration that can be analogous to a jacketed, multiport corrosion cell.
Equipment mapping: A jacketed flat corrosion cell with multiport access for reference, counter electrode, and gas purge, combined with temperature control to maintain physiological temperature (typically 37 °C), closely matches the apparatus description used in published F2129 testing.
7.2 ASTM F746 — Pitting or Crevice Corrosion of Metallic Surgical Implant Materials
ASTM F746, Standard Test Method for Pitting or Crevice Corrosion of Metallic Surgical Implant Materials, covers the determination of resistance to either pitting or crevice corrosion of metals and alloys intended for surgical implant manufacture, applicable only to passive metals and alloys. It is explicitly designed and intended for use as a comparative laboratory screening test to rank candidate implant alloys in order of their relative resistance to localised corrosion under the specific severe conditions the test imposes.
The standard’s own documentation notes that the test is intentionally designed to be severe enough to cause breakdown of at least one alloy (Type 316L stainless steel) that is currently considered acceptable for surgical implant use, and explicitly cautions that alloys which suffer localised corrosion under this test’s more severe portions do not necessarily suffer equivalent corrosion when actually implanted in the human body. A direct head-to-head comparison published in the peer-reviewed literature found that F2129 produced more visible corrosion than F746 across four common implant alloys, and additionally found that F746 falsely identified crevice corrosion in cases where visual inspection found no actual evidence of crevice attack — concluding that F2129 was the more effective method overall for evaluating crevice corrosion susceptibility in this material set.
8 EIS-Specific Standards and Instrument Verification
Electrochemical impedance spectroscopy occupies a slightly different position in the ASTM corrosion standards family compared to the polarisation methods above. Rather than a dedicated test method standard for running EIS on bare corroding metal, ASTM’s primary EIS-specific document is the instrument verification practice covered in Section 2.3 (G106). This is a meaningful structural difference from the ISO approach, where EIS on coated and uncoated specimens has its own dedicated four-part standard family.
In practice, ASTM-aligned corrosion labs running EIS on bare metal coupons typically use ASTM G106 to verify instrument performance, then apply the general conventions of G3 and the corrosion-rate calculation framework of G102 to interpret the resulting Nyquist or Bode data, without a separate ASTM “how to run EIS on a corroding metal” test method standard in the way G5 governs anodic polarisation.
For EIS-capable instruments and coating-evaluation setups, see EIS-capable potentiostats and coating evaluation cells.
9 Master Decision Matrix — Standard, Technique, and Equipment
| Standard | What It Covers | Technique | Recommended Cell | Potentiostat Mode |
|---|---|---|---|---|
| ASTM G3 | Sign and plotting conventions (reference document, not a test) | — | — | — |
| ASTM G102 | Corrosion rate calculation from electrochemical data | Calculation framework | — | Applied after any polarisation test |
| ASTM G106 | EIS instrumentation, technique and data-presentation verification | EIS verification using standardised verification setup/procedure | G106-appropriate verification cell or dummy/reference setup | EIS verification / instrument check |
| ASTM G5 | Potentiodynamic anodic polarisation | DC polarisation sweep | Flat corrosion cell | Potentiodynamic |
| ASTM G59 | Polarisation resistance (LPR) | Small-amplitude DC sweep at E₀corr | Flat corrosion cell | LPR |
| ASTM G61 | Cyclic polarisation for localised corrosion | Forward/reverse DC sweep | Flat or jacketed flat corrosion cell | Cyclic polarisation |
| ASTM G69 | Corrosion potentials of aluminium alloys | OCP / corrosion-potential monitoring; high-impedance potential measurement versus a defined reference scale | Flat corrosion cell + corrosion specimen holder + stable Ag/AgCl reference electrode | OCP / corrosion-potential monitoring |
| ASTM G82 | Development and use of a galvanic series to predict galvanic corrosion behaviour | Measure and rank corrosion potentials of candidate materials in the same environment and exposure conditions | Flat corrosion cell or general electrochemical cell with stable reference-electrode access | OCP / potential measurement and long-term potential logging |
| ASTM G96 | Online corrosion monitoring in plant equipment | ER monitoring and LPR-style monitoring with plant probes | 5-port corrosion cell or jacketed flat corrosion cell for laboratory simulation | Long-term monitoring / LPR or polarisation-resistance mode |
| ASTM G189 | Laboratory simulation of corrosion under insulation (CUI) | CUI-cell exposure with optional electrochemical monitoring | Dedicated CUI-cell / pipe-insulation simulation fixture; jacketed flat corrosion cell for preliminary temperature-controlled coupon studies only | Temperature/exposure logging; optional OCP, LPR, EIS or resistance monitoring |
| ASTM G215 | Electrode potential measurement guide | Reference-electrode measurement practice | Reference electrodes with the relevant corrosion cell; Ag/AgCl reference electrode for routine aqueous corrosion work | Potential measurement quality control; OCP / polarised-potential measurement across all corrosion methods |
| ASTM G217 | Coupled multielectrode array sensor (CMAS) corrosion monitoring | CMAS / coupled multielectrode array monitoring | CMAS probe or custom multielectrode-array sensor; bench adaptation via 5-port corrosion cell or general electrochemical cell | Multichannel low-current monitoring / CMAS mode |
| ASTM G220 | Replacing saturated calomel reference electrodes (SCE) | Reference-electrode substitution and potential-scale conversion | Ag/AgCl reference electrode / reference electrodes | Reference-electrode selection and potential conversion; applies to all potential-controlled/measurement modes |
| ASTM G100 | Cyclic galvanostaircase polarisation | Stepped current with reversal | Flat corrosion cell | Galvanostatic staircase |
| ASTM G150 | Critical pitting temperature | Constant potential, temperature ramp | Jacketed flat corrosion cell (crevice-free configuration — confirm with technical team) | Potentiostatic with temperature ramp |
| ASTM G192 | Crevice repassivation potential | 3-stage: potentiodynamic / galvanostatic / potentiostatic | Multiport flat corrosion cell with crevice former | Combined 3-stage sequence |
| ASTM G108 | Sensitisation detection (EPR), 304/304L stainless | Double-loop anodic passivation + reactivation | Flat corrosion cell | EPR (cyclic anodic/cathodic) |
| ASTM G71 | Galvanic corrosion between dissimilar metals | Galvanic couple exposure; optional ZRA measurement | Dual-coupon galvanic cell or flat corrosion cell adapted for two dissimilar metals | ZRA / galvanic-current monitoring where required |
| ASTM B825 | Surface film / tarnish characterisation | Constant-current coulometric (cathodic) reduction | Flat corrosion cell or general electrochemical cell | Galvanostatic (constant current) |
| ASTM G199 | Electrochemical noise measurement | Passive potential/current monitoring, no applied signal | Flat corrosion cell, multi-electrode configuration | Electrochemical noise (low-noise EN mode) |
| ASTM G185 | Inhibitor screening under flow | LPR / Tafel with rotating cylinder electrode | Dedicated RCE assembly — contact technical team | LPR, Tafel |
| ASTM G148 | Hydrogen uptake / permeation | Devanathan-Stachurski permeation | Dedicated dual-compartment permeation cell — contact technical team | Potentiostatic (detection side) |
| ASTM F2129 | Implant device corrosion susceptibility | Cyclic potentiodynamic polarisation, whole device | Jacketed flat corrosion cell, multiport, 37 °C | Cyclic polarisation |
| ASTM F746 | Implant material pitting/crevice screening | Cyclic potentiodynamic polarisation, coupon | Jacketed flat corrosion cell, multiport | Cyclic polarisation |
| EIS on coatings (ASTM D8370 for field coating/lining EIS) | Coating impedance evaluation | AC impedance sweep | Coating evaluation cell | EIS |
10 Practical Considerations Before You Start Testing
Electrolyte purity and preparation: Several of the standards above specify exact electrolyte concentrations (3.5% NaCl for G61, phosphate buffered saline for F2129, for example) precisely because small deviations change the corrosion behaviour being measured. Prepare electrolytes gravimetrically with deionised water and reagent-grade salts, and discard electrolyte that has been open to air for extended periods if dissolved CO₂ or oxygen content is a variable of concern for your specific test.
Reference electrode stability: Ag/AgCl and saturated calomel (SCE) reference electrodes drift over time, particularly in chloride-rich corrosion electrolytes where junction potential changes can occur. Check reference electrode potential against a known standard before any test series that will be used for quantitative corrosion rate comparison across multiple specimens or multiple days.
Specimen surface preparation: All polarisation methods are highly sensitive to surface finish — variation in surface roughness, residual oxide, or contamination between specimens introduces variability that is often mistaken for genuine material differences. A published G61 application example used mechanical polishing followed by alternating ultrapure water and isopropanol rinses immediately prior to immersion; treat this as an example of controlled surface preparation, not as a universal ASTM surface-preparation requirement. Standardise this procedure across all specimens in a comparative study and document it in your methods section.
Crevice artefacts: Any cell configuration that seals against a flat specimen with a gasket creates the possibility of crevice corrosion at the gasket-to-specimen interface — this is a particular concern for the pitting- and crevice-focused standards in Section 4, where an artefactual crevice can trigger pit or crevice initiation that has nothing to do with the bulk material's genuine resistance. Inspect the specimen after testing for pit or crevice location relative to the gasket boundary to rule out this artefact.
Choosing between similar-sounding standards: Several standards in this guide use the same fundamental technique — cyclic potentiodynamic polarisation — on different specimen classes (G61 for general alloys, F2129 for whole implant devices, F746 for implant material coupons). Confirm you are using the standard matched to your specimen type and intended application, since the acceptance criteria, electrolyte, and apparatus details differ between them even where the underlying electrochemical principle is the same.
11 Frequently Asked Questions
For broader questions about ScienceGears products, ordering, and shipping, visit our main FAQ page. For broader product selection guidance, see how to choose the right corrosion test electrochemical cell.
Q1 Which ASTM standard do I need for general corrosion rate vs localised pitting corrosion?
For a general, uniform corrosion rate on a metal exposed to a known electrolyte, ASTM G59 (LPR) is the standard method — it is fast, minimally destructive, and directly produces a corrosion rate via ASTM G102's calculation framework. For localised corrosion susceptibility specifically, ASTM G61's cyclic polarisation method is the most widely used choice, with ASTM G100 (cyclic galvanostaircase polarisation) as an alternative galvanostaircase method for suitable alloy systems, especially where its aluminium-alloy origins and current-step approach are appropriate. If your specific concern is crevice corrosion at a geometric crevice such as a gasket or threaded joint, ASTM G192 is the more targeted and rigorous method, since it is specifically designed around determining the repassivation potential of an initiated crevice rather than a general pitting susceptibility screen.
Q2 What is the difference between ASTM G61, ASTM G100, and ASTM G192 — don’t they all measure localised corrosion?
They measure related but distinct aspects of localised corrosion behaviour using different control modes. G61 sweeps potential continuously in a forward-and-reverse cycle and reads the hysteresis behaviour. G100 uses a stepped current (galvanostaircase) control mode and was developed around aluminium alloy 3003-H14, although it may guide work on other alloys; it should not be presented as a direct G61 substitute across all alloy classes. G192 is structurally different again — it combines three sequential control modes (potentiodynamic, then galvanostatic, then potentiostatic) specifically to determine the repassivation potential of a deliberately initiated crevice, which is a more specific and more rigorous measurement than the general pitting susceptibility screen that G61 and G100 provide.
Q3 My G61 cyclic polarisation curve shows no hysteresis loop — does this mean my material has no pitting susceptibility?
A negative hysteresis result (the reverse scan tracking back along or below the forward scan, with no positive loop) is generally interpreted as low susceptibility to localised corrosion under the tested conditions — but confirm this is not an artefact before drawing that conclusion. Check that your anodic scan actually reached a current density threshold sufficient to break down the passive film (the standard or selected protocol specifies a current or current-density reversal criterion); if the scan reversed too early, the absence of a hysteresis loop may simply reflect that the test never probed conditions severe enough to initiate pitting, rather than genuine pitting resistance.
Q4 Do I need to run ASTM G106 instrument verification before every test, or just once when I set up new equipment?
ASTM G106 verification is most critical when commissioning new potentiostat hardware, after any significant change to cabling or cell configuration, and periodically (for example, quarterly) as a quality control check even on established equipment. It is not necessary before every individual EIS measurement, but any lab generating EIS data intended for publication or formal quality control reporting should be able to demonstrate a documented G106 verification history for the instrument used.
Q5 Is ASTM F2129 the same test as ASTM G61, just applied to medical devices?
The underlying electrochemical principle is the same — cyclic potentiodynamic polarisation — but the specimen, electrolyte, and intended application differ meaningfully. G61 is run on flat coupon material samples in a chloride electrolyte (typically 3.5% NaCl) to characterise localised corrosion susceptibility of the bulk alloy. F2129 is run on whole, finished implant devices (stents, clips, occluders, and similar) in a physiological saline electrolyte such as phosphate buffered saline, specifically because the device’s final geometry, surface finish, and any fabrication-induced residual stress can all influence corrosion susceptibility in ways that a flat coupon test of the same alloy would not reveal. A peer-reviewed comparison of F2129 against the related ASTM F746 method found F2129 to be the more effective of the two for evaluating crevice corrosion in modular implant interfaces.
Q6 Where does ASTM B825 fit if it isn’t measuring active corrosion?
B825 is best understood as a film characterisation technique rather than a corrosion-rate or susceptibility test. It is typically used after a specimen has already undergone a separate exposure test — for example, an environmental gas exposure test on an electrical contact material — to quantify how much tarnish or oxide film has built up on the surface as a result of that exposure. The coulometric reduction current and time are used to calculate the relative film thickness or charge. It is included in this guide because it uses the same potentiostat/galvanostat hardware platform as every other method here, and because major instrument suppliers include it in their corrosion-relevant standards documentation, but its measurement objective is meaningfully different from G5, G59, or G61.
12 Expert Support — How ScienceGears Works Alongside Your Research
Selecting the correct ASTM standard is only the first decision. Configuring the cell, electrolyte, reference electrode, and potentiostat programming to genuinely comply with that standard’s specified conditions is where most of the practical difficulty lies — and where many reproducibility problems in corrosion testing can arise.
ScienceGears is founded and directed by PhD-trained electrochemists with direct experience running ASTM-aligned corrosion test programmes across polarisation, LPR, cyclic polarisation, localised corrosion, and EIS methods. When you contact us with a specific standard and material in mind, you are talking to someone with practical experience configuring ASTM-aligned electrochemical corrosion tests — not reading from a product catalogue.
What Expert Support Looks Like in Practice
Standard-to-Equipment Mapping for Your Specific Test
If you are setting up a corrosion test programme against a specific ASTM standard and are unsure which corrosion cell configuration, electrode materials, or potentiostat mode are appropriate, contact us before ordering. We will confirm the correct cell volume, port configuration, and material compatibility for your specific electrolyte and standard.
Crevice-Free and Crevice-Forming Cell Configuration
For ASTM G61 and G150 testing, where unintended gasket-induced crevice artefacts can compromise data validity, our technical team can advise on cell sealing configurations and specimen preparation procedures specifically designed to minimise this risk. Conversely, for ASTM G192 testing, where a defined and reproducible crevice geometry is the deliberate experimental requirement, we can advise on appropriate crevice-forming washer assemblies.
Specialised Hardware for G185 and G148
Rotating cylinder electrode assemblies for inhibitor screening (G185) and dual-compartment hydrogen permeation cells (G148) fall outside our standard flat and jacketed corrosion cell range. Contact us to discuss configuration options for these specialised test programmes.
Instrument Verification Support
If you are establishing an ASTM G106 verification procedure for a new or existing potentiostat, we can advise on dummy cell configuration and the expected impedance spectrum your specific instrument should reproduce.
Complete System Supply
ScienceGears supplies the complete corrosion testing system as a single integrated recommendation:
- Corrosion test electrochemical cells — flat, jacketed flat, coating evaluation, 5-port, and specimen holders
- Potentiostats and galvanostats with corrosion-specific modes
- General electrochemical cells
- Application notes
Local AU/NZ Stock for Selected Items
Selected corrosion cells and accessories are often held in local Australian inventory, subject to current stock availability. When your test programme requires a specific cell configuration at short notice, you are not waiting 4–8 weeks for international freight.
“An ASTM standard tells you what to measure and under what conditions — it does not, by itself, tell you how to seal a crevice-free specimen, which reference electrode is stable in your specific electrolyte, or how to verify your instrument before you trust the data. That is the part we help with.” — ScienceGears Technical Team
Further Reading — Related ScienceGears Resources
- → How to Choose the Right Corrosion Test Electrochemical Cell
- → Corrosion Test Electrochemical Cell Range
- → Flat Corrosion Cell
- → Jacketed Flat Corrosion Cell
- → Coating Evaluation Cell
- → Potentiostats and Galvanostats
- → Application Notes
External Reference
- → ASTM Subcommittee G01.11 on Electrochemical Measurements in Corrosion Testing — current standards jurisdiction listing — the authoritative current listing of all active ASTM electrochemical corrosion test standards referenced in this guide
