1、Designation: G119 09 (Reapproved 2016)Standard Guide forDetermining Synergism Between Wear and Corrosion1This standard is issued under the fixed designation G119; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last rev
2、ision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide covers and provides a means for computingthe increased wear loss rate attributed to synergism or interac-tion that
3、may occur in a system when both wear and corrosionprocesses coexist. The guide applies to systems in liquidsolutions or slurries and does not include processes in agas/solid system.1.2 This guide applies to metallic materials and can be usedin a generic sense with a number of wear/corrosion tests. I
4、t isnot restricted to use with approved ASTM test methods.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bil
5、ity of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2G3 Practice for Conventions Applicable to ElectrochemicalMeasurements in Corrosion TestingG5 Reference Test Method for Making PotentiodynamicAnodic Polarization MeasurementsG15 Terminology Relating to Corrosion and
6、 Corrosion Test-ing (Withdrawn 2010)3G40 Terminology Relating to Wear and ErosionG59 Test Method for Conducting Potentiodynamic Polariza-tion Resistance MeasurementsG102 Practice for Calculation of Corrosion Rates and Re-lated Information from Electrochemical Measurements3. Terminology3.1 Definition
7、sFor general definitions relating to corro-sion see Terminology G15. For definitions relating to wear seeTerminology G40.3.2 Definitions of Terms Specific to This Standard:3.2.1 cathodic protection current density, icpthe electricalcurrent density needed during the wear/corrosion experiment tomainta
8、in the specimen at a potential which is one volt cathodicto the open circuit potential.3.2.2 corrosion current density, icorthe corrosion currentdensity measured by electrochemical techniques, as describedin Practice G102.3.2.3 electrochemical corrosion rate, Cthe electrochemi-cal corrosion rate as
9、determined by Practice G59 and convertedto a penetration rate in accordance with Practice G102. Thispenetration rate is equivalent to the volume loss rate per area.The term Cwis the electrochemical corrosion rate during thecorrosive wear process, and the term C0designates the elec-trochemical corros
10、ion rate when no mechanical wear is al-lowed to take place.3.2.4 mechanical wear rate, W0the rate of material lossfrom a specimen when the electrochemical corrosion rate hasbeen eliminated by cathodic protection during the wear test.3.2.5 total material loss rate, Tthe rate of material lossfrom a sp
11、ecimen exposed to the specified conditions, includingcontributions from mechanical wear, corrosion, and interac-tions between these two.3.2.6 wear/corrosion interactionthe change in materialwastage resulting from the interaction between wear andcorrosion, that is, T minus W0and C0. This can be sub-d
12、ividedinto Cw, the change of the electrochemical corrosion rate dueto wear and Wc, the change in mechanical wear due tocorrosion.4. Summary of Guide4.1 A wear test is carried out under the test conditions ofinterest and T is measured.4.2 Additional experiments are conducted to isolate themechanical
13、and corrosion components of the corrosive wearprocess. These are as follows:4.2.1 Arepeat of the experiment in 4.1 with measurement ofCw,1This guide is under the jurisdiction of ASTM Committee G02 on Wear andErosion and is the direct responsibility of Subcommittee G02.40 on Non-AbrasiveWear.Current
14、edition approved June 1, 2016. Published June 2016. Originallyapproved in 1993. Last previous edition approved in 2009 as G119 09. DOI:10.1520/G0119-09R16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM
15、Standards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2.2 A
16、test identical to the initial experiment in 4.1, exceptthat cathodic protection is used to obtain W0, and4.2.3 Measurement of C0, the corrosion rate in the absenceof mechanical wear.4.3 Cwand Wcare calculated from the values measuredin the experiments described in 4.1 and 4.2.5. Significance and Use
17、5.1 Wear and corrosion can involve a number of mechanicaland chemical processes. The combined action of these pro-cesses can result in significant mutual interaction beyond theindividual contributions of mechanical wear and corrosion(1-5).4This interaction among abrasion, rubbing, impact andcorrosio
18、n can significantly increase total material losses inaqueous environments, thus producing a synergistic effect.Reduction of either the corrosion or the wear component ofmaterial loss may significantly reduce the total material loss. Apractical example may be a stainless steel that has excellentcorro
19、sion resistance in the absence of mechanical abrasion, butreadily wears and corrodes when abrasive particles remove itscorrosion-resistant passive film. Quantification of wear/corrosion synergism can help guide the user to the best meansof lowering overall material loss. The procedures outlined inth
20、is guide cannot be used for systems in which any corrosionproducts such as oxides are left on the surface after a test,resulting in a possible weight gain.6. Procedures6.1 A wear test where corrosion is a possible factor isperformed after the specimen has been cleaned and prepared toremove foreign m
21、atter from its surface. Volume loss rates perunit area are then calculated, and the results tabulated. Thevalue of T is obtained from these measurements. Examples ofwear tests involving corrosion are detailed in papers containedin the list of references. These examples include a slurry weartest (1-3
22、), a slurry jet impingement test (6), and a rotatingcylinder-anvil apparatus (7).6.2 A wear test described in 6.1 is repeated, except that thewear specimen is used as a working electrode in a typical 3electrode system. The other two electrodes are a standardreference electrode and a counter electrod
23、e as described inPractices G3 and G59, and Reference Test Method G5. Thistest is for electrochemical measurements only, and no mass orvolume losses are measured because they could be affected bythe electrical current that is passed through the specimen ofinterest during the experiments. Two measurem
24、ents are made,one to measure the polarization resistance as in Practice G59,and one to generate a potentiodynamic polarization curve as inTest Method G5. The open circuit corrosion potential, Ecor, thepolarization resistance, Rp, and Tafel constants, aand c, aretabulated. The exception to Test Metho
25、d G5 is that theapparatus, cell geometry, and solutions or slurries used aredefined by the particular wear test being conducted, and are notrestricted to the electrochemical cell or electrolyte described inTest Method G5. The potentiodynamic method rather than thepotentiostatic method is recommended
26、. Rp, a, and care usedto calculate the electrochemical corrosion current density, icoras described in Practice G59. The value for icoris thenconverted to a penetration rate in accordance to Practice G102.This penetration rate is equivalent to the material loss rate, Cw.6.3 A wear test similar to tha
27、t conducted in 6.2 is run againexcept that the wear specimen is polarized one volt cathodicwith respect to Ecorso that no corrosion takes place. The massloss of the specimen is measured during the cathodic protectionperiod by weighing it before and after the test. W0is thencalculated by dividing the
28、 mass loss by the specimen densityand exposed surface area. The current density icpis alsorecorded. Caution must be used when using this techniquebecause some metals or alloys may be affected by hydrogenembrittlement as a result of hydrogen that may be generatedduring this test. If hydrogen evolutio
29、n is too great, then there isalways a possibility that the hydrodynamics of the systemcould be affected. However, the results of research (1-7) haveshown these effects to be minimal for the ferrous alloys studiedto date.6.4 A corrosion test similar to that conducted in 6.2 is runagain except no mech
30、anical wear is allowed to act on thespecimen surface. The penetration rate, which is equivalent toC0, is obtained as in 6.2, using polarization resistance andpotentiodynamic polarization scans to obtain Rp, a, b, andicor.6.5 T, W0,C,Cwand C0are all reported in units of volumeloss per exposed area pe
31、r unit time. The synergism betweenwear and corrosion is calculated according to (Eq 1), (Eq 2),and (Eq 3).6.6 Caution must be used to make sure that the surface areaexposed to corrosion is the same as that exposed to mechanicalwear. Coating of the portions of the specimen with a non-conductor to mas
32、k off areas to prevent corrosion is an effectivemeans of doing this.7. Calculation of Wear/Corrosion Interaction7.1 The total material loss, T, is related to the synergisticcomponent, S, that part of the total damage that results from theinteraction of corrosion and wear processes, by the followinge
33、quationT 5 W01C01S (1)7.2 The total material loss, T, can be divided into thefollowing components, the wear rate in the absence ofcorrosion, the corrosion rate in the absence of wear, and thesum of the interactions between the processes:T 5 W01C01Cw1Wc(2)where Cwis the change in corrosion rate due t
34、o wear andWcis the change in wear rate due to corrosion.Wc5 W01Wc(3)where Wcis the total wear component of T.Cw5 C01Cw(4)where Cwis the total corrosion component of T and can bemeasured by electrochemical means.4The boldface numbers in parentheses refer to the list of references at the end ofthis st
35、andard.G119 09 (2016)27.3 The term “synergistic effect” is now usually used torefer to the enhancement of wear due to corrosion Wc.Negative synergism (or antagonism) occurs when the corrosionproduct during wear provides better protection than the initialsurface; an example would be the formation of
36、adherent oxidescale during sliding wear. The term “additive effect” refers tothe change in corrosion rate due to wear, Cw. In the lattercase, the electrochemical corrosion rate, can be added to thewear rate in the absence of corrosion, W0, to generate theoverall weight change.From the above, the fol
37、lowing dimensionless factors can bedefined to describe the degree of synergism:T/(TS) (“Total Synergism Factor”) (i)(C0+ Cw)/C0(“Corrosion Augmentation Factor”) (ii)(W0+ Wc)/W0(“Wear Augmentation Factor”) (iii)7.4 Construction of Wear-Corrosion MapA wear-corrosion map is a useful method of identifyi
38、ng wastageregimes and mechanisms (5, 8, 9). The following is a methodwhich enables a wear-corrosion map to be constructed.7.4.1 Generate at least six test results involving the samevariables identifying the components of the interaction given inSection 7, that is, results at six velocities.7.4.2 For
39、 each of these results, generate an additional sixtests (identifying the components of the interaction given inSection 7) on the effects of another variable, that is, particlesize or pH.7.4.3 Identify criteria for transitions between tribo-corrosion regimes:T,X Low (5)X # T,X1 Medium (6)T $ X2 High
40、(7)7.4.4 The limits in 7.4.3 should be based on tolerancesidentified for the wear-corrosion process. The Low region isidentified as the safe operating wear-corrosion regime. Thevarious regimes should be labeled on the map.7.4.5 The map can also be used to identify the extent of thewear and corrosion
41、 augmentation factors by defining criteriafor the transitions (8, 9) between regimes.Cw/Wc,0.1 (8)Synergistic effects dominate. Corrosion is affecting wear to agreat extent than wear is affecting corrosion.0.1 # Cw/Wc,1 (9)The “additive” and “synergistic” interactions are equal.Cw/Wc$ 1 (10)Additive
42、 effects dominate. Wear is affecting corrosion to agreater extent than corrosion is affecting wear.7.4.6 As in 7.4.4, the various regimes should be highlightedon the map.7.4.7 If the synergistic effects are negative in Eq 8-10, thatis, antagonistic, use the same inequalities but take the modulusof W
43、cin the evaluation of Cw/Wcin the determination ofthe regime boundaries.8. Report58.1 The report should include the test method used and thetest conditions.8.2 Asample of a Test Data Recording form is shown in Fig.1.8.3 A sample of a Test Summary form for several tests isshown in Fig. 2.9. Keywords9
44、.1 aqueous; corrosion; electrochemical; erosion-corrosion;slurries; solutions; synergism; wear5See appendixes for examples of parameter calculations and test data.TEST Test Number:DATE Date:ENVIRONMENT Description:SPECIMEN Material property Wear Specimen Counterface MaterialIdentification: Density,
45、g/cm3Specimen area, mm2Equivalent weightWEAR TESTS Initial wt, g Final wt, g Wt loss, g Time, hMaterial loss,mm3mm2Material loss rate,mm3mm22yrMaterial loss ratesymbolCorrosive WearTestTCathodicProtection TestW0ELECTRO-CHEMICALTESTSEcor,mVvsSCE icor, A/cm2Rp, ohms-cm2 a,mVdecadec,mVdecadeMaterial lo
46、ss rate,mm3mm22yrMaterial loss ratesymbolElectrochemicaltest with wearCwElectrochemicaltest without wearC0FIG. 1 Test Data Recording FormG119 09 (2016)3APPENDIXES(Nonmandatory Information)X1. SAMPLES OF TEST DATATEST Test Number:DATE Date:ENVIRONMENT Description:SPECIMEN Material property Wear Speci
47、men Counterface MaterialIdentification: Density, g/cm37.83 1032 wt pct silica sand (50 70 mesh) in water slurryA514 steel Specimen area, mm2654 25CEquivalent weight 27.92WEAR TESTS Initial wt, g Final wt, g Wt loss, g Time, hMaterial loss,mm3mm2Material loss rate,mm3mm22 yrMaterial lossrate symbolCo
48、rrosive Wear Test 56.3057 56.0793 0.2264 1.00 0.044 387 TCathodic Protection Test 56.0495 55.9035 0.1460 1.00 0.029 249 W0ELECTROCHEMICALTESTSEcor,mVvsSCE icor, A/cm2Rp, ohms-cm2a,mV3decadec,mV3decadeMaterial loss rate,mm3mm22 yrMaterial lossrate symbolElectrochemical testwith wear519 322 80.4 95 16
49、0 3.75 CwElectrochemical testwithout wear420 180 102 90 80 2.10 C0X2. SAMPLE OF TEST SUMMARYTEST SPECIMEN COUNTERFACE MATERIALMaterial loss rate,mm3mm22yr Unitless factorsTW0C0CwS CwWcCorrosionaugmentationWearaugmentation1 A514 steel2 wt pct silica sand (50 70) in water slurry 25C387 249 2.10 3.75 136 134 1.65 1.79 1.542 316 SS2 wt pct silica sand (50 70) in water slurry 25C427 272 0.465 9.95 154 145 9.49 21.4 1.533 REM 5002 wt pct silica sand (50 70) in water slurry 25C222 168 0.990 1.27 53.0 52.7 0.3
