wc12％co热喷涂粉末及其涂层制备的研究

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1、摘要利用烧结破碎法制备了WC．12％Co热喷涂原料粉末，用爆炸喷涂法制备了WC．12％Co涂层。主要采用x一射线衍射(Ⅺ①)、扫描电子显微镜(sEM)、能谱分析(EDS)对热喷涂原料粉末及其涂层的形貌和结构进行了研究。综合分析了烧结温度、原始WC颗粒大小、添加有机粘结剂、添加碳粉对热喷涂原料粉末特性的影响；分析了涂层的形成机理，探讨了粉末特性对涂层相组成和结构的影响，并与大气等离子喷涂法制备的WC／Co涂层进行了比较。对烧结破碎法制备的热喷涂粉末的研究结果表明：细颗粒WC(FSSS粒度为0．68um

2、)要比粗颗粒WC(FSSS粒度为3．56um)烧结程度大，制备出的粉末更加致密；1250℃是制备超细颗粒WC热喷涂原料粉末(45～751-1m)较好的烧结温度；将有机粘结剂(PvA)混入粉末，有利于制备大颗粒WC．12％Co热喷涂原料粉末；添加碳粉在热喷涂粉末中主要以游离态形式存在，可有效抑止超细WC粉烧结时q(C03W3C)等有害相的出现。对爆炸喷涂法制备的涂层的研究结果表明：WC．12％Co涂层组织均匀、致密，涂层截面层状组织不明显，喷涂过程中发生了轻微脱碳；与大气等离子喷涂法相比，爆炸喷涂法制

3、备的WC．12％Co涂层更致密，涂层脱碳程度较轻。关键词：WC—Co，烧结破碎，热喷涂，耐磨涂层ABSTRACTWC一12％Cofeedstockpowderforthermalsprayingwaspreparedbysinter-crushingmethod，andthecoatingwassprayedbydetonationgunspraying．Themorphologyandthemicrostructureofthefeedstockpowderandcoatingwereinvest

4、igatedbyX-raydiffraction，scanningelectronmicroscopyandenergy—dispersivespectroscopy．Theinfluencesofthesinteringtemperature，theparticlesizeofstartingWCpowder，organicbinderandcarboncontentonthefeedstockpowdercharacteristicswereinvestigated．Themechanismfo

5、rmicrostructuraldevelopmentofthecoatingandtheeffectoffeedstockpowdercharacteristicsonthephaseconstituentandthemicrostmctureofthecoatingwerestudied．Thecoatingsdepositedbydetonationgunsprayingandbyairplasmasprayingwerecompared．Theexperimentalresultsofthe

6、feedstockpowderpreparedbysinter-crushingmethodareasfollows．Thefeedstockpowder(45～7511m)madefromfineWC(O．689m)thanfromcoarseWC(3．56tma)ismorecompactbecausethedegreeofsinteringismoresufficient．1250*Cisabettersinteringtemperatureforpreparingultra·-finegra

7、inWC·-12％Cofeedstockpowderforthermalspraying．Organicbinder(eVA)addedintotherawpowderspromotessintefingprocess．TheaddedcarbonexistsmainlyinfreestateinthepreparedpowderandiseffectiveinpreventingtheformationofT1(C03W3C)andothernon—WCphases．Theexperimental

8、resultsofthecoatingdepositedbydetonationgunareasfollows．ThemorphologyofWC一12％Cocoatingwithoutobviouslayerstructureishomogeneousanddense．Decarbonizationduringdetonationgunspayingisnotserious．Comparedwiththecoatingdepositedbyairplasmaspra