自蔓延高温合成WC粉末的结晶行为

Crystallization behavior of self-propagating high temperature synthesis WC powder

以黑钨矿(Fe(Mn)WO_(4))、黄钨(WO_(3))、电石(CaC_(2))和高纯铝粉为主要原料,采用自蔓延高温合成法(self-propagating high-temperature synthesis,SHS)制备单晶WC粉末,研究添加铝热剂(Fe_(3)O_(4)-Al混合物,n(Fe_(3)O_(4)):n(Al)=3:8)、原料预热和投料量对WC粉末粒度和形貌特征的影响。结果表明:用SHS法制备的WC粉末晶型完整;添加铝热剂会生成大量Fe3W3C相,导致WC粉末的纯度降低;对坩埚内的原料粉末预热会使WC晶粒充分生长,WC粉末粒度增大,同时WC晶粒形貌由球形转变为多边形;增加反应物料投料量会使WC粉末粒径增大,粉末形貌由球形转变为多边形。

Single crystal WC powder was prepared by self-propagating high temperature synthesis (SHS) with wolframite(Fe(Mn)WO_(4)),tungsten (WO3),calcium carbide (CaC_(2)) and high purity aluminum powders as main raw materials.The effects of thermite addition (Fe3O4-Al mixture,n(Fe_(3)O_(4)):n(Al)=3:8),preheating of raw material and feeding amount on particle size and morphology characteristics of the WC powder were studied.The results show that the crystal shape of the WC powder prepared by SHS method is complete.Although the temperature of combustion system is increased with adding thermite,a large number of Fe3W3C phases are formed,resulting in a decrease in the purity of WC powder.Preheating the raw powders in the crucible can make the WC grain grow fully.The size of the WC powder becomes larger,and the WC crystal shape changes from spherical to multilateral shape.The particle size of the WC powder increases with the increase of the feeding amount of reaction material,and the shape of WC powder changes from spherical to polygonal.