6559

6124

كارشناسي ارشد

مهندسي مواد

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مهندسي مواد

1390

سيزده، 105ص.: مصور، جدول، نمودار

ص.ع. به فارسي و انگليسي

مهدي صالحي، مهدي احمديان

15/1/90

محمد حسين عنايتي، رضا بخشي

1396/10/10

كتابنامه

مواد

مهندسي مواد

ID6124

به فارسي و انگليسي: قابل رويتدر نسخه ديجيتالي

Study of the Properties of Developed WC FeAl B Coating Sprayed by HVOF Omid Mehrabani O mehrabani@ma iut ac ir Date of Submission 7 18 2011 Department of Materials Engineering Isfahan University of Thechnology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor s Mehdi Salehi surfacesalehi@hotmail comSupervisor s Mehdi Ahmadian ahmadian@cc iut ac irAbstractIn this work the influence of the type of binder cobalt and iron aluminide intermetallic on microstructure mechanical properties and wear resistance of high velocity oxy fuel HVOF sprayed tungsten carbide basedhardmetal coating was studied Intermetallic binder with different amount of boron 0 0 05 and 0 1 weightpercent B were produced using vacuum arc melting and cast chill prepared under controlled atmosphereusing ring grinding blended with tungsten carbide powder 7 m and then sintered and crushed intoparticles large enough to flow in the spray equipment The mechanical and wear properties of theintermetallic composite coating compared with the prepared conventional cobalt binder coatingWC 30 vol Co and commercial coating WC 20 vol Co The coating characterization included opticalmicroscopy and scanning electron microscopy of metallugraphically prepared cross section hardness andtoughness measurement phase composition by X ray diffraction and wear behavior by ball on disk Based onx ray diffraction result the proportion of WC transformed to W2C is higher for all of the WC Co comparedwith the WC FeAl B Coating and in WC Co coating no traces of carbide phases Co6W6C Co3W3C were observed Result showed that the hardness of WC FeAl Coatings is higher than those WC Co coatings The toughness was found to be improved when boron doped with iron aluminide in intermetallic matrixcomposite coatings The study of wear tracks indicated that the dominant wear mechanism in both WC Coand WC FeAl B coating was carbide pull out and subsurface fracture The iron aluminide binder dopedwith 0 05 wt boron had lower coefficient of friction and weight loss than the other coating even withcommercial coating WC 20 vol Co witch has a lower percentage of binder phase and tungsten carbideparticle size 0 7 m were competitive In addition the friction and wear behavior at elevated temperatureand failure mechanism of coatings were investigated The result indicated that the sliding wear resistance ofWC FeAl 0 05B coating is higher than that of WC Co coating at high temperature Subsurface fracture carbide pull out and WC grain break dominant in both coating but in WC Co coating followed with extrusionof the supporting binder phase and adhesive wear WC FeAl B coating showed an improvement in wearproperties at low temperature and significantly at high temperature than WC Co coating KeywordsComposite coating Tungsten carbide Iron alumonide Thermal spray HVOF Wear Toughness

مهدي صالحي، مهدي احمديان

محمد حسين عنايتي، رضا بخشي