1、Designation: G 119 09Standard 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 () 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 may occur in a s
3、ystem 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. It isnot restrict
4、ed 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-bility of regulator
5、y limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2G3 Practice for ConventionsApplicable to ElectrochemicalMeasurements in Corrosion TestingG5 Reference Test Method for Making Potentiostatic andPotentiodynamic Anodic Polarization MeasurementsG15 Terminology Relating to Corrosion a
6、nd CorrosionTestingG40 Terminology Relating to Wear and ErosionG59 Test Method for Conducting Potentiodynamic Polar-ization Resistance MeasurementsG 102 Practice for Calculation of Corrosion Rates andRelated Information from Electrochemical Measurements3. Terminology3.1 DefinitionsFor general defini
7、tions 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 tomaintain the specimen at
8、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 G 102.3.2.3 electrochemical corrosion rate, Cthe electrochemi-cal corrosion rate as determined by Prac
9、tice G59 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 no
10、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 to t
11、he 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-dividedinto DCw, the
12、 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 com
13、ponents of the corrosive wearprocess. These are as follows:4.2.1 Arepeat 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 mechan
14、ical 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 July 15, 2009. Published August 2009. Originallyapproved in 1993. Last previous edition approved in 2004 as G
15、11904.2For 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, P
16、O 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-cesses
17、 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.Reduction
18、 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 itsc
19、orrosion-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,r
20、esulting 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 rep
22、eated, 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 G3andG59, and Reference Test Method G5. Thistest is for electrochemical measurements only, an
23、d 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 G59,and one to generate a potentiodynamic polariza
24、tion curve as inTest Method G5. The open circuit corrosion potential, Ecor, thepolarization resistance, Rp, and Tafel constants, baand bc, aretabulated. The exception to Test Method G5 is that theapparatus, cell geometry, and solutions or slurries used aredefined by the particular wear test being co
25、nducted, and are notrestricted to the electrochemical cell or electrolyte described inTest Method G5. The potentiodynamic method rather than thepotentiostatic method is recommended. Rp, ba, and bcare usedto calculate the electrochemical corrosion current density, icoras described in Practice G59. Th
26、e 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 Ecorso tha
27、t 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. Caution must be u
28、sed 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. However, the
29、 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 obtained as
30、in 6.2, using polarization resistance andpotentiodynamic polarization scans to obtain Rp, ba, bb, andicor.6.5 T, W0,C,Cwand 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 3).6.6 Cauti
31、on 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 Interaction7.1
32、 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, the wear rate
33、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 andDWcis the change in wear rate due to corrosion.Wc5 W01DWc(3)where Wcis the total wear component o
34、f T.Cw5 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 during wear pro
35、vides better protection than the initialsurface; an example would be the formation of adherent oxide3The boldface numbers in parentheses refer to the list of references at the end ofthis standard.G119092scale during sliding wear. The term “additive effect” refers tothe change in corrosion rate due t
36、o wear, DCw. 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 following dimensionless factors can bedefined to describe the degree of synergism:T/(TS) (“Total Synergism Factor
37、”) (i)(C0+ DCw)/C0(“Corrosion Augmentation Factor”) (ii)(W0+ DWc)/W0(“Wear Augmentation Factor”) (iii)7.4 Construction of Wear-Corrosion MapA wear-corrosion map is a useful method of identifying wastageregimes and mechanisms (5, 8, 9). The following is a methodwhich enables a wear-corrosion map to b
38、e 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 each of these results, generate an additional sixtests (identifying the components of the interaction given
39、 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 (7)7.4.4 The limits in 7.4.3 should be based on tolerancesidentified for the wear-corrosion process. The Low
40、 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 augmentation factors by defining criteriafor the transitions (8, 9) between regimes.DCw/DWc, 0.1 (8)Synergi
41、stic effects dominate. Corrosion is affecting wear to agreat extent than wear is affecting corrosion.0.1#DCw/DWc, 1 (9)The “additive” and “synergistic” interactions are equal.DCw/DWc$1 (10)Additive effects dominate. Wear is affecting corrosion to agreater extent than corrosion is affecting wear.7.4.
42、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 DWcin the evaluation of DCw/DWcin the determination ofthe regime boundaries).8. Report48.1 The report sh
43、ould 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. Keywords9.1 aqueous; corrosion; electrochemical; erosion-corrosion;slurries; solutions; synergism; wear4See
44、appendixes for examples of parameter calculations and test data.TEST Test Number:DATE Date:ENVIRONMENT Description:SPECIMEN Material property Wear Specimen Counterface MaterialIdentification: Density, g/cm3Specimen area, mm2Equivalent weightWEAR TESTS Initial wt, g Final wt, g Wt loss, g Time, hMate
45、rial loss,mm3mm2Material loss rate,mm3mm22yrMaterial loss ratesymbolCorrosive WearTestTCathodicProtection TestW0ELECTRO-CHEMICALTESTSEcor,mVvsSCE icor, A/cm2Rp, ohms-cm2 ba,mVdecadebc,mVdecadeMaterial loss rate,mm3mm22yrMaterial loss ratesymbolElectrochemicaltest with wearCwElectrochemicaltest witho
46、ut wearC0FIG. 1 Test Data Recording FormG119093APPENDIXES(Nonmandatory Information)X1. SAMPLES OF TEST DATATEST Test Number:DATE Date:ENVIRONMENT Description:SPECIMEN Material property Wear Specimen Counterface MaterialIdentification: Density, g/cm37.83 3 1032 wt pct silica sand (50 3 70 mesh) in wa
47、ter 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,mm3mm22yrMaterial lossrate symbolCorrosive Wear Test 56.3057 56.0793 0.2264 1.00 0.044 387 TCathodic Protection Test 56.0495 55.9035 0.14
48、60 1.00 0.029 249 W0ELECTROCHEMICALTESTSEcor,mVvsSCE icor, A/cm2Rp, ohms-cm2ba,mV3decadebc,mV3decadeMaterial loss rate,mm3mm22yrMaterial lossrate symbolElectrochemical testwith wear519 322 80.4 95 160 3.75 CwElectrochemical testwithout wear420 180 102 90 80 2.10 C0X2. SAMPLE OF TEST SUMMARYTEST SPEC
49、IMEN COUNTERFACE MATERIALMaterial loss rate,mm3mm22yrUnitless factorsTW0C0CwS DCwDWcCorrosionaugmentationWearaugmentation1 A514 steel2 wt pct silica sand (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 1.31X3. SAMPLE CALCULATION FOR TOTAL MATERIAL LOSS RATEX3.1 DataX3.1.1 Corrosive Wear Test duration1 h.X3.1.2 Specimen Density7.84 g/cm
