Concluding Remarks Theresults ofthisstudyshowed thattheCSEM-Ti andtheCSEM-AI coatings gavemuchlonger endurance livesinairthantheothercoatings thatwereevaluated. Asstatedearlier, TeerCoatings Ltd hasthepatentrightstotheMoS2-Ti coating andthetechnology hasbeenlicensed toCSEM. Themost probable reason whytheTeer-Ti coating gaveshorter endurance livesascompared totheCSEM-Ti coating wasthattheTeercoating wasformulated withlesstitanium forvacuum use,thusitwouldnotbe expected toworkaswellinair.Evenso,thecoating wearratewasnearlyequalbetween thetwocoatings indryair;soifthesamethickness oftheTeer-Ti coating hadbeenapplied, thelifeprobably wouldhave beenequivalent. Butinmoistair,theCSEM-Ti coating wearratewasmuchlessthantheTeer-Ti coating, whichindicates thatinhumidair,moretitanium isnecessary. Indrynitrogen, ontheBlock-on-Ring Tribometer, theendurance livesforthetwofilmswerenearlyequivalent, buttheweartotheblocksthat slidontheTeer-Ti coating wasmuchlessthanfoundwiththeCSEM-Ti coating. Theresultsindicate that thereshouldbeamoredetailed studytodetermine howmuchTishouldbeaddedtoprevent degradation andreasonable lifeinambient airwhilegivingoptimal lifeandperformance invacuurn. Increased thickness ofthecoatings whichcontained additives (andwerealsoabletosupport theloadof thesliding440Cballcounterface) tendedtogiveincreased life.Itisnotbelieved thatincreased thickness ofthenon-additive MovicorSurftech coatings inairwouldhaveimproved thelifeconsiderably because theyfailedprimarily duetodegradation ofthecoatings. Testswereconducted innitrogen usingtheBlock-on-Ring Tribometer because thisgeometry simulates a journal bearing moreclosely thatdoesaPin-on-Disk configuration; ajournal bearing contact iscloserto linecontact thanpointcontact. Therewereseveral drawbacks withusingthisTribometer, however. Misalignment oftheblockwiththeringandwobble oroutofroundness oftheringareacouple; thuswith thisTribometer, itisveryhardtoperfectly alignthesurfaces. Misalignment cancausehighcontact stress thatcanprematurely causefailureofasolidlubricant coating. ItisfeltthattheCSEM-Ti coatedonboth surfaces, helped mitigate thismisalignment. Alsothicker coatings couldbehelpful inmitigating misalignment providing thatthecoating wouldnotexperience brittlefracture duringthe"run-in." The CSEM-AI coating wasverybrittlethustherewasnoadvantage ofslidingitagainst itself.Slidingablock coated withCSEM-Ti against theMoviccoating wasnotadvantages sincetheCSEM-Ti coating is somewhat roughandveryhard,thusitpromoted morerapidwearoftheMoviccoating. Considering alltheresults, theHohman coating, whichwasdeveloped bytheAirForce[18]andlicensed toHohman Plating, functioned overallasthebestcoating forourapplication undertheconditions ofall theexperiments. Thelowestfriction coefficients andlongest endurance liveswereobtained withthis coating. TheCSEM-Ti gaveexceptional resultsinairandalsoexceptional resultswhenboththeringand theblockwerecoated. ItmaybethattheTeer-Ti coating ortheothercoatings mighthaveworked aswell innitrogen ifbothblocksandringswerecoatedwiththesamematerial, butinthisstudythoseconditions werenotevaluated. Thenextplanned stageforthisprogram istotakethebestcoatings determined bythisinvestigation and testtheminvacuum inajournal bearing at50,000 rpmundertheconditions thattheymayencounter ina flywheel system touchdown eventtodetermine whichwillperform thebestintheactualenduse application. Thepoorendurance liferesults obtained indrynitrogen withtheSurftech andCSEM-AI coatings donotmakethemcandidates forthenextphaseoftesting. Theshortendurance lifeoftheMovic coating inmoistairanddegradation ofthecoating onthedisksurface indryairalsodiscourages their useforthisapplication. References 1.Winer,W.O.,"Molybdenum Disulfide asaLubricant: AReview oftheFundamental Knowledge," Wear,10,(1967), 422-452. 2.Johnson, R.L.,"AReview oftheEarlyUseofMolybdenum Disulfide asaLubricant," NASATMX 52343(1967). NASA/CP--2002-211506 317