Study on Two-Step Synthesis of WC-Co Composite Powder and Its Sintering Performance AITranslate

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Chinese Library Classification Number:TG135.5[一般工业技术—材料科学与工程]

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Using ammonium metatungstate as the source of tungsten,cobalt nitrate as the source of cobalt and sucrose as the source of carbon,WC-Co composite powder was successfully synthesized through a twostep method combining liquid phase method and reduction carbonization method,and then WC-Co cemented carbide was prepared by sintering.The influences of different reduction carbonization temperatures on the phase composition,particle morphology,particle size and sintering formability of WC-Co composite powder were studied using XRD,SEM,EDS,FT-IR,microhardness tester and other methods.The micromorphology and particle size of experimentally prepared WC-Co composite powder and cemented carbide were compared and analyzed with commercial WC-Co composite powder and cemented carbide.The results show that the reduction carbonization temperature significantly affects the microstructure of the powder.At 900~1200℃,decarbonized phases such as Co₃W₃C and Co₃W₉C exist in the WC-Co composite powder.At 1300~1400℃,the reaction is complete and only WC and Co phases remain.As the reduction carbonization temperature increases,the particle size of the WC-Co composite powder gradually increases(about 0.21μm at 900℃and 0.97μm at 1400℃).The morphological evolution is as follows:equiaxed→equiaxed,rod-like,and flake-like→equiaxed→locally rod-like.Compared with commercial WC-Co cemented carbides,the cemented carbide prepared by sintering WC-Co composite powder subjected to reduction carbonization at 1300℃exhibits more uniform distribution of W,C,and Co elements,but has relatively low relative density(72.93%)and hardness(5.6 GPa).