ASTM B826-09
(Test Method)Standard Test Method for Monitoring Atmospheric Corrosion Tests by Electrical Resistance Probes
Standard Test Method for Monitoring Atmospheric Corrosion Tests by Electrical Resistance Probes
SIGNIFICANCE AND USE
Corrosivity monitoring of test environments provides a means to monitor an integrated value of test corrosivity which cannot be evaluated from test parameters themselves, such as temperature, humidity, and gas concentration. As such the monitor value can be used for specification purposes such as test validation. Electrical resistance monitoring of conductors exposed to corrosive media is a well-established practice. , , ,
The resistance method assumes uniform corrosion over the entire surface of the exposed metal conductor segment. Local corrosion such as pitting, crevice, or grain boundary corrosion may provide invalid estimates of test corrosivity. Marked changes in slope of the curve of electrical resistance ratio versus time may indicate undesired processes which can be due to deficiencies in the test atmosphere or in the monitor itself.
Because of limitations of the diffusion process within the corrosion product formed on the metal conductor segment of the RM probe when passivating corrosion films are formed, resistance monitoring may not be useful for test chamber monitoring purposes for very long test exposures. Chamber monitoring is dependent on detecting changes in the rate of corrosion of the RM as an indicator signal that specified gas concentrations must be reverified. However, low corrosion rates limit the absolute value of the rate of change of corrosion rate with change of test conditions; for parabolic film growth processes, the growth rate decreases with time limiting the sensitivity of the RM at extended test times.
Since corrosion rate can be a complex function of test parameters in MFG tests with any given metal primarily responsive to a subset of the gases in the MFG environment, more than one type metal resistance probe is required in order to assist in maintenance of relative gas concentrations. For such test specifications, values of resistance ratios must be referred to ratios obtained under known test conditions as supplied by the ...
SCOPE
1.1 This test method provides a means for monitoring corrosivity of environmental tests that involve exposure to corrosive gases.
1.2 This test method uses a resistance monitor (RM) probe fabricated from a chosen metal conductor, with one conductor segment uncovered to permit exposure of the chosen metal conductor to the corrosive gas mixture and the second conductor segment covered to protect the metal conductor of this segment from direct attack by the corrosive gas mixture. The covered conductor segment provides a reference for evaluating changes in the uncovered segment. The ratio of the resistance of the exposed segment to that of the covered segment provides a measure of the amount of metal conductor that has reacted with the corrosive gas test environment to form poorly conducting corrosion product, thus providing a measure of test corrosivity.
1.3 Resistance monitoring is applicable to a broad range of test conditions by selection of the appropriate metal conductor and initial metal thickness.
1.4 This method is similar in intent to Test Methods B808.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to become familiar with all hazards including those identified in the appropriate Material Safety Data Sheet (MSDS) for this product/material as provided by the manufacturer, to establish appropriate safety and health practices, and determine the applicability of regulatory limitations prior to use.
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Designation: B826 − 09
StandardTest Method for
Monitoring Atmospheric Corrosion Tests by Electrical
1
Resistance Probes
This standard is issued under the fixed designation B826; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2
2.1 ASTM Standards:
1.1 This test method provides a means for monitoring
B808 TestMethodforMonitoringofAtmosphericCorrosion
corrosivity of environmental tests that involve exposure to
Chambers by Quartz Crystal Microbalances
corrosive gases.
B810 Test Method for Calibration ofAtmospheric Corrosion
1.2 This test method uses a resistance monitor (RM) probe
Test Chambers by Change in Mass of Copper Coupons
fabricated from a chosen metal conductor, with one conductor
B827 Practice for Conducting Mixed Flowing Gas (MFG)
segment uncovered to permit exposure of the chosen metal
Environmental Tests
conductor to the corrosive gas mixture and the second conduc-
G96 Guide for Online Monitoring of Corrosion in Plant
tor segment covered to protect the metal conductor of this
Equipment (Electrical and Electrochemical Methods)
segment from direct attack by the corrosive gas mixture. The
covered conductor segment provides a reference for evaluating
3. Summary of Test Method
changes in the uncovered segment. The ratio of the resistance
3.1 The corrosivity of an atmospheric corrosion test such as
oftheexposedsegmenttothatofthecoveredsegmentprovides
a mixed flowing gas (MFG) type test is measured by monitor-
a measure of the amount of metal conductor that has reacted
ing the loss in electrical conductivity of a metal element whose
with the corrosive gas test environment to form poorly con-
surface corrodes to form poorly conducting corrosion product.
ducting corrosion product, thus providing a measure of test
Thiscorrosionproductconsumesmetalfromaconductionpath
corrosivity.
causing an increase in electrical resistance. The resistance of
the degraded conduction path is compared with a similar path
1.3 Resistance monitoring is applicable to a broad range of
whose surface is covered to prevent corrosion. This compari-
test conditions by selection of the appropriate metal conductor
sonresistancealsoprovidesatemperaturecorrectionreference.
and initial metal thickness.
The ratio of the electrical resistance of the path exposed to the
1.4 This method is similar in intent to Test Methods B808.
corrosive gases to that of the covered path is monitored during
thetestandcomparedtoanexpectedratio-versus-timecurveto
1.5 The values stated in SI units are to be regarded as
establish the relationship of the test corrosivity to expected test
standard. No other units of measurement are included in this
corrosivity. Alternatively, the ratio-versus-time curve for a
standard.
given atmosphere can be compared with the behavior of other
1.6 This standard does not purport to address all of the
corrosiveatmospherestoevaluatetherelativecorrosivityofthe
safety concerns, if any, associated with its use. It is the
various atmospheres.
responsibility of the user of this standard to become familiar
with all hazards including those identified in the appropriate
4. Significance and Use
Material Safety Data Sheet (MSDS) for this product/material
4.1 Corrosivity monitoring of test environments provides a
as provided by the manufacturer, to establish appropriate
means to monitor an integrated value of test corrosivity which
safety and health practices, and determine the applicability of
cannot be evaluated from test parameters themselves, such as
regulatory limitations prior to use.
temperature, humidity, and gas concentration. As such the
monitor value can be used for specification purposes such as
1
This test method is under the jurisdiction of ASTM Committee B02 on
Nonferrous Metals and Alloysand is the direct responsibility of Subcommittee
2
B02.11 on Electrical Contact Test Methods. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Oct. 1, 2009. Published December 2009. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1997. Last previous edition approved in 2003 as B826 - 03. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/B0826-09. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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B826 − 09
test validation. Electrical resistance monitoring of conductors product, which grows out from the edges of the conductor
3,4,5,6
...
This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:B826–03 Designation:B826–09
Standard Test Method for
Monitoring Atmospheric Corrosion Tests by Electrical
1
Resistance Probes
This standard is issued under the fixed designation B826; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method provides a means for monitoring corrosivity of environmental tests that involve exposure to corrosive
gases.
1.2 This test method uses a resistance monitor (RM) probe fabricated from a chosen metal conductor, with one conductor
segment uncovered to permit exposure of the chosen metal conductor to the corrosive gas mixture and the second conductor
segment covered to protect the metal conductor of this segment from direct attack by the corrosive gas mixture. The covered
conductorsegmentprovidesareferenceforevaluatingchangesintheuncoveredsegment.Theratiooftheresistanceoftheexposed
segment to that of the covered segment provides a measure of the amount of metal conductor that has reacted with the corrosive
gas test environment to form poorly conducting corrosion product, thus providing a measure of test corrosivity.
1.3 Resistance monitoring is applicable to a broad range of test conditions by selection of the appropriate metal conductor and
initial metal thickness.
1.4 This method is similar in intent to Test Methods B808.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to become familiar with all hazards including those identified in the appropriate Material Safety Data
Sheet (MSDS) for this product/material as provided by the manufacturer, to establish appropriate safety and health practices, and
determine the applicability of regulatory limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
B808 Test Method for Monitoring of Atmospheric Corrosion Chambers by Quartz Crystal Microbalances
B810 Test Method for Calibration of Atmospheric Corrosion Test Chambers by Change in Mass of Copper Coupons
B827 Practice for Conducting Mixed Flowing Gas (MFG) Environmental Tests
G96 Guide for Online Monitoring of Corrosion in Plant Equipment (Electrical and Electrochemical Methods)
3. Summary of Test Method
3.1 The corrosivity of an atmospheric corrosion test such as a mixed flowing gas (MFG) type test is measured by monitoring
the loss in electrical conductivity of a metal element whose surface corrodes to form poorly conducting corrosion product. This
corrosion product consumes metal from a conduction path causing an increase in electrical resistance. The resistance of the
degraded conduction path is compared with a similar path whose surface is covered to prevent corrosion. This comparison
resistance also provides a temperature correction reference. The ratio of the electrical resistance of the path exposed to the
corrosive gases to that of the covered path is monitored during the test and compared to an expected ratio-versus-time curve to
establish the relationship of the test corrosivity to expected test corrosivity. Alternatively, the ratio-versus-time curve for a given
atmosphere can be compared with the behavior of other corrosive atmospheres to evaluate the relative corrosivity of the various
atmospheres.
4. Significance and Use
4.1 Corrosivity monitoring of test environments provides a means to monitor an integrated value of test corrosivity which
1
This test method is under the jurisdiction of ASTM Committee B02 on Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee B02.11 on
Electrical Contact Test Methods.
Current edition approved June 10, 2003. Published July 2003. Originally approved in 1997. Last previous edition approved in 1997 as B826-97. DOI: 10.1520/B0826-03.
Current edition approved Oct. 1, 2009. Published December 2009. Originally approved in 1997. Last previous edition approved in 2003 as B826 - 03. DOI:
10.1520/B0826-09.
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
, Vol 03.04.volume information, refer to the standard’s Document Summary page on the ASTM website.
Co
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