1、Designation: G 119 04Standard Guide forDetermining Synergism Between Wear and Corrosion1This standard is issued under the fixed designation G 119; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number
2、in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide provides a means for computing the in-creased wear loss rate attributed to synergism or interactionthat may occur in a system when
3、 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. It isnot restricted to use
4、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-bility of regulatory limitati
5、ons prior to use.2. Referenced Documents2.1 ASTM Standards:G 3 Practice for Conventions Applicable to ElectrochemicalMeasurements in Corrosion Testing2G 5 Reference Test Method for Making Potentiostatic andPotentiodynamic Anodic Polarization Measurements2G 15 Terminology Relating to Corrosion and Co
6、rrosionTesting2G 40 Terminology Relating to Wear and Erosion2G 59 Practice for Conducting Potentiodynamic PolarizationResistance Measurements2G 102 Practice for Calculation of Corrosion Rates andRelated Information from Electrochemical Measurements23. Terminology3.1 DefinitionsFor general definition
7、s relating to corro-sion see Terminology G 15. For definitions relating to wear seeTerminology G 40.3.2 Definitions of Terms Specific to This Standard:3.2.1 cathodic protection current density, icpThe electri-cal current density needed during the wear/corrosion experi-ment to maintain the specimen a
8、t a potential which is one voltcathodic to the open circuit potential.3.2.2 corrosion current density, icorThe corrosion currentdensity measured by electrochemical techniques, as describedin Practice G 102.3.2.3 electrochemical corrosion rate, CThe electrochemi-cal corrosion rate as determined by Pr
9、actice G 59 and con-verted to a penetration rate in accordance with Practice G 102.This penetration rate is equivalent to the volume loss rate perarea. The term Cwis the electrochemical corrosion rate duringthe corrosive wear process, and the term C0designates theelectrochemical corrosion rate when
10、no mechanical wear isallowed 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 specimen exposed t
11、o 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 Woand Co. This can be sub-dividedinto DCw,
12、the change of the electrochemical corrosion rate dueto wear and DWc, 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 and corrosion
13、components of the corrosive wearprocess. These are as follows:4.2.1 A repeat of the experiment in 4.1 with measurement ofCw,4.2.2 A 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 me
14、chanical wear.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 edition approved May 1, 2004. Published May 2004. Originallyapproved in 1993. Last previous edition approved in 2003 as G 1
15、19 03 .2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive,
16、PO Box C700, West Conshohocken, PA 19428-2959, United States.4.3 DCwand DWcare calculated from the values measuredin the experiments described in 4.1 and 4.2.5. Significance and Use5.1 Wear and corrosion can involve a number of mechanicaland chemical processes. The combined action of these pro-cesse
17、s can result in significant mutual interaction beyond theindividual contributions of mechanical wear and corrosion(1-5).3This interaction among abrasion, rubbing, impact andcorrosion can significantly increase total material losses inaqueous environments, thus producing a synergistic effect.Reductio
18、n 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 excellentcorrosion resistance in the absence of mechanical abrasion, butreadily wears and corrodes when abrasive particles remove its
19、corrosion-resistant passive film. Quantification of wear/corrosion synergism can help guide the user to the best meansof lowering overall material loss. The procedures outlined inthis guide cannot be used for systems in which any corrosionproducts such as oxides are left on the surface after a test,
20、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 matter from its surface. Volume loss rates perunit area are then calculated, and the results tabulated. Thevalue of T is
21、 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), a slurry jet impingement test (6), and a rotatingcylinder-anvil apparatus (7).6.2 A wear test described in 6.1 is re
22、peated, 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 electrode as described inPractices G 3 and G 59, and Reference Test Method G 5. Thistest is for electrochemical measurements on
23、ly, 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 measurements are made,one to measure the polarization resistance as in Practice G 59,and one to generate a potentiodynamic p
24、olarization curve as inTest Method G 5. The open circuit corrosion potential, Ecor, thepolarization resistance, Rp, and Tafel constants, baand bc, aretabulated. The exception to Test Method G 5 is that theapparatus, cell geometry, and solutions or slurries used aredefined by the particular wear test
25、 being conducted, and are notrestricted to the electrochemical cell or electrolyte described inTest Method G 5. The potentiodynamic method rather than thepotentiostatic method is recommended. Rp, ba, and bcare usedto calculate the electrochemical corrosion current density, icoras described in Practi
26、ce G 59. The value for icoris thenconverted to a penetration rate in accordance to Practice G 102.This penetration rate is equivalent to the material loss rate, Cw.6.3 A wear test similar to that conducted in 6.2 is run againexcept that the wear specimen is polarized one volt cathodicwith respect to
27、 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 mass loss by the specimen densityand exposed surface area. The current density icpis alsorecorded. Cautio
28、n 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 evolution is too great, then there isalways a possibility that the hydrodynamics of the systemcould be affected. H
29、owever, 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 mechanical wear is allowed to act on thespecimen surface. The penetration rate, which is equivalent toC0, is o
30、btained as in 6.2, using polarization resistance andpotentiodynamic polarization scans to obtain Rp, ba, bb, andicor.6.5 T, W0,C,Cw, and C0are all reported in units of volumeloss per exposed area per unit time. The synergism betweenwear and corrosion is calculated according to (Eq 1), (Eq 2),and (Eq
31、 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 mask off areas to prevent corrosion is an effectivemeans of doing this.7. Calculation of Wear/Corrosion I
32、nteraction7.1 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 followingequationT 5 W01 C01 S (1)7.2 The total material loss, T, can be divided into thefollowing components, t
33、he wear rate in the absence of corro-sion, the corrosion rate in the absence of wear, and the sum ofthe interactions between the processes:T 5 W01 C01DCw1DWc(2)where DCwis the change in corrosion rate due to wear and DWcis thechange in wear rate due to corrosionWc5 W01DWc(3)where Wcis the total wear
34、 component of TCw5 C01DCw(4)where Cwis the total corrosion component of T and can bemeasured by electrochemical means.7.3 The term “synergistic effect” is now usually used torefer to the enhancement of wear due to corrosion DWc.Negative synergism (or antagonism) occurs when the corrosionproduct duri
35、ng wear provides better protection than the initial3The boldface numbers in parentheses refer to the list of references at the end ofthis standard.G119042surface; an example would be the formation of adherent oxidescale during sliding wear. The term “additive effect” refers tothe change in corrosion
36、 rate due to wear, DCw. In the lattercase, the electrochemical corrosion rate, can be added to thewear rate in the absence of corrosion, Wo, to generate theoverall weight change.From the above, the following dimensionless factors can bedefined to describe the degree of synergism:T/(T S) (“Total Syne
37、rgism Factor”) (i)(Co+ DCw)/Co(“Corrosion Augmentation Factor”) (ii)(W0+ DWc)/W0(“Wear Augmentation Factor”) (iii)8. Report48.1 The report should include the test method used and thetest conditions.8.2 A sample of a Test Data Recording form is shown in Fig.1.8.3 A sample of a Test Summary form for s
38、everal tests isshown in Fig. 2.9. Keywords9.1 aqueous; corrosion; electrochemical; erosion-corrosion;slurries; solutions; synergism; wear4See appendixes for example of parameter calculations and test data.TEST Test Number:DATE Date:ENVIRONMENT Description:SPECIMEN Material property Wear Specimen Cou
39、nterface MaterialIdentification: Density, 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
40、, ohms-cm2 ba,mVdecadebc,mVdecadeMaterial loss rate,mm3mm22yrMaterial loss ratesymbolElectrochemicaltest with wearCwElectrochemicaltest without wearC0FIG. 1 Test Data Recording FormG119043APPENDIXES(Nonmandatory Information)X1. SAMPLES OF TEST DATATEST Test Number:DATE Date:ENVIRONMENT Description:S
41、PECIMEN Material property Wear Specimen Counterface MaterialIdentification: Density, g/cm37.83 3 1032 wt pct silica sand (50 3 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 r
42、ate,mm3mm22yrMaterial lossrate symbolCorrosive 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 W0ELECTROCHEMICAL TESTS Ecor,mVvsSCE icor, A/cm2Rp, ohms-cm2ba,mV3decadebc,mV3decadeMaterial loss rate,mm3mm22yrMaterial lossrate symbolElect
43、rochemical test with wear 519 322 80.4 95 160 3.75 CwElectrochemical test without wear 420 180 102 90 80 2.10 C0X2. SAMPLE OF TEST SUMMARYTEST SPECIMEN COUNTERFACE MATERIALMaterial loss rate,mm3mm22yrUnitless factorsT W0C0CwS DCwDWcCorrosionaugmentationWearaugmentation1 A514 steel2 wt pct silica san
44、d (50 3 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 3 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 3 70) in water slurry 25C222 168 0.990 1.27 53.0 52.7 0.3 1.28 1.31TEST SPECIMENCOUNTERFACEMATER
45、IALMaterial loss rate,mm3mm22yrUnitless factorsT W0C0CwS DCwDWcCorrosionaugmentationWearaugmentationFIG. 2 Test Summary FormG119044X3. SAMPLE CALCULATION FOR TOTAL MATERIAL LOSS RATEX3.1 Data:X3.1.1 Corrosive Wear Test duration1 h.X3.1.2 Specimen Density7.84 g/cm3.X3.1.3 Specimen Area654 mm2.X3.1.4
46、Initial mass of sample56.3057 g.X3.1.5 Final mass of sample56.0793 g.X3.2 Calculation.T 5F56.3057 g 2 56.0793 g654 mm23 7.84 3 1023gmm33 1hG3 24hd3 365dyr5 387mm3mm22yr(X3.1)X4. SAMPLE CALCULATION FOR MECHANICAL WEAR RATEX4.1 Data:X4.1.1 Mechanical Wear Rate in mm2/mm2-yr.X4.1.2 Cathodic Protection
47、Test duration1 h.X4.1.3 Specimen Density7.84 g/cm3.X4.1.4 Specimen Area654 mm2.X4.1.5 Initial mass of sample56.0495 g.X4.1.6 Final mass of sample55.9035 g.X4.2 Calculation:W05F56.0495 g 2 55.9035 g654 mm23 7.84 3 1023gmm33 1hG3 24hd3 365dyr5 249mm3mm22yr(X4.1)X5. SAMPLE CALCULATION FOR ELECTROCHEMIC
48、AL CORROSION RATESX5.1 Data and requirementsSee Appendix X1.X5.1.1 Corrosion Rate in mm3/mm2-yr.X5.1.2 Exposed Surface Area = 654 mm2.X5.1.3 icorfor test with wear322 A/cm2.X5.1.4 icorfor test without wear180 A/cm2.X5.1.5 Specimen Equivalent Weight27.92 (See AppendixX2 in Practice G 102 for sample c
49、alculation).X5.2 CalculationsSee Practice G 102, Appendix X3 forcalculation of penetration rate.Cw53.27 3 1023mm2gA2cm2yr3 322Acm23 27.927.84gcm35 3.75mmyr5 3.75mm3mm22yr(X5.1)C053.27 3 1023mm2gA2cm2yr3 180Acm23 27.927.84gcm35 2.10mmyr5 2.10mm3mm22yr(X5.2)X6. SAMPLE CALCULATION FOR AMOUNT OF SYNERGISMX6.1 Data and requirementsSee Appendix X3, AppendixX4, and Appendix X5.X6.2 Calculation in accordance with (Eq 1).S 5 T 2 W02 C05 387 2 249 2 2.1 5 135.9mm3mm22yr(X6.1)X6.3 Calculation in accordance with (Eq 2).DWc5 T 2 W02 Cw5 387
