XRD Benchmark Evaluation Method for Solid Solution Content of Grain Inhibitors in Tungsten Carbide Powder
Adding grain inhibitors to fine tungsten oxide or tungsten powder to produce tungsten carbide powder containing inhibitors is a method for preparing ultrafine cemented carbides.It is generally believed that inhibitors in WC powder are either solidly soluble in the WC phase or exist as independent phases.However,due to the small amount added,it is difficult to determine its phase or solidsolution content through examining methods.This article attempts to establish quantitative indicators through benchmark evaluation to determine the degree of solid solution of grain inhibitors in powders,and evaluates the fine and ultrafine WC powders prepared by adding different amounts of Cr and Cr,V mixed grain inhibitors.The test result indicates that difficulty in determining the solid solution amountis due to the neglect of the carbon deficient phase and corresponding solid solution product phase during production.The evaluation method uses W2C,(W,Cr,V)2C and WC as benchmark objects to determine the solid solution amount.The diffraction peak position and full width at half max imumare used as benchmark indicators to weaken the influence of other factors that interfere with lattice constant changes,such as uncertainty of crystal type caused by fewer spectral peaks,and changes in crystallization degree caused by process parameters or inhibitor addition.Within the range of 1%inhibitor addition,the peak positions of(W,Cr,V)2C and WC in the powder increase with the addition of Cr inhibitor,and the peak area of(W,Cr,V)2C also shows a gradually increasing trend.Sample powders are prepared as cemented carbide and measured for WC grain size,and some results show that the trend is consistent with quantitative indicators.
NETL
NSTL
万方数据
