矫顽磁力在纤维状WC晶粒硬质合金研究中的应用  

The application of coercive force in studying on cemented carbide with fibrous WC grain

作　　者：曹顺华[1] 邹仕民[1] 李春香[1] 谢继峰[1] 李文超[1] 张秀芳[1] 

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《粉末冶金技术》2008年第5期328-331,335,共5页Powder Metallurgy Technology

摘　　要：利用高能球磨制备的纳米晶W（Co，C）过渡相粉末制备了纤维状WC硬质合金。采用X射线衍射（XRD）分析球磨粉末及不同温度烧结样品的相组成，并计算WC晶粒尺寸；通过矫顽力研究高能球磨粉末Co的存在方式以及固相烧结阶段粉末相转变和晶粒长大行为。结果表明：球磨粉末中矫顽力由0（球磨时间22h）逐渐增加，Co先固溶在W晶格中，随球磨时间增加析出；烧结温度为700～900℃时，矫顽力由0急剧增加，η相分解析出单磁畴的Co，WC晶粒长大较慢；烧结温度为1050～1250℃时，矫顽力下降，大量多磁畴Co出现，WC晶粒长大速度加快；烧结温度为900～1050℃时，矫顽力几乎不变，WC晶粒长大缓慢；烧结温度超过1250℃时，矫顽力缓慢增加，Co相晶型发生改变。The cemented carbide with fibrous WC grain was fabricated using nano-grain W（Co, C） transitional phase powders prepared by high energy ball milling. Phase constitution of as-milled powder and sintered samples at different temperature were analyzed by XRD, and grain size of WC was calculated by XRD analysis software. Via coercive force analysis, existence characteristics of Co in ball milling process, phase transformation of as-milled powder and grain growing behavior in solid phase sintering course were discussed. The result shows that Co dissolves in W crystal firstly, and then precipitates when milling time is more than 22 hours; When sintering temperature is at between 700 and 900℃, coercive force increases suddenly from 0, single magnetic domain Co appears from decomposition of η phase, and WC grain grows slowly; When the temperature is between 1 050 and 1 250℃, coercive force decreases, a great deal of multidomain Co appears and WC grain grows rapidly; When the temperature is between 900 and 1 050℃, coercive force does not changed, and WC grain grows very slowly; When the temperature is more than 1 250℃, coercive force increases slowly, which attribute to transformation of Co to β crystal.

关 键 词：矫顽力 纤维状WC 硬质合金 

分 类 号：TQ175.79[化学工程—硅酸盐工业] TG135.5[一般工业技术—材料科学与工程]