Study On Preparation Technology Of Yttrium-Containing Tungsten Carbide Powder

Rare earth elements are often used to improve the strength and wear resistance of cemented carbides,in order to further improve the uniform distribution of rare earth elements in cemented carbides and improve the stability of cemented carbides.In this paper,APT powder containing Y was prepared by coprecipitation and pressure cooking,and WC powder was prepared by calcination,reduction and carbonization.The effect of Y on WC powder containing impurity Si was studied.The phase composition of samples at different stages was determined by XRD,the morphology of powder samples was observed by SEM,and the particle size was determined by image statistics.The main conclusions are as follows:(1)WC powder containing Y was prepared by coprecipitation and pressure cooking.Y existed mainly in the form of oxides and carbides of Y in WC.(2)The average particle sizes of WC powders prepared by direct carbonization of tungsten yellow with Y content of 0%,0.05%,0.1% and 1% were 1.55,1.42,1.38 and 0.90 microns,respectively.The average primary particle size is 0.35,0.29,0.27 and 0.21 microns,respectively.The average particle sizes of WC powders prepared by direct carbonization of violet tungsten with Y content of 0%,0.05%,0.1% and 1% were 1.53,1.13,1.08 and 0.71 microns,respectively.The average primary particle size is 0.29,0.27,0.25 and 0.21 microns,respectively.It can be found that the average particle size of WC powders prepared by direct carbonization of violet tungsten containing the same content of Y is smaller than that of WC powders prepared by carbonization of yellow tungsten.Compared with the coprecipitation method,the WC powder prepared by calcination and direct carbonization of Y-containing APT prepared by pressure cooking method has better dispersion and similar particle size.(3)Wolframite was prepared by calcining APT of 1wt%Y+0.1wt%Si and 1wt%Y+1wt%Si.The average primary particle size of WC powders prepared by direct carbonization is 0.29 and 0.20 microns,respectively.Purple tungsten was prepared by calcination of APT containing 1wt%Y+0.1wt%Si and 1wt%Y+1wt%Si.The average particle size of WC powder prepared by direct carbonization was 0.28 and 0.25 microns,respectively.Compared with WC prepared by blank APT without other elements,the secondary particle size of WC powder prepared by Y and Si composite addition is larger and the average particle size fluctuation of primary particle is smaller.