WC-10％Co超细硬质合金烧结中表面钴聚集的形成

摘要

通过分析合金表面形貌、表面物相和表面钴含量,研究了WC-10 ％Co超细晶粒硬质合金烧结时表面Co聚集的形成过程.结果表明:在1 100℃下烧结50 min后,合金表面出现典型的颈缩和孔隙球化,表面Co含量达54.12％,产生了表面Co聚集； 在1 250℃、1 300℃、1 320℃、1 330℃、1 350℃下烧结10 min后,合金表面均未见明显颈缩和孔隙球化,1 320℃下开始在表面大孔隙处产生Co聚集,1 330℃下渗出到表面出现孤岛状表面Co聚集,表面出现Co(hcp)相,Co含量达71.63％,1 350℃下相互串联形成网络状Co聚集层,表面Co(hcp)相增多,Co含量达86.32％；1 350℃下烧结30 min后表面网络状Co聚集层部分消退,显露出Co聚集层下的WC晶粒,表面Co(hcp)相减少,表面Co含量82.81％；1 410℃下烧结50 min后,合金表面网络状Co聚集层明显消退,WC晶粒成片显露出来,表面Co(hcp)相消失,表面Co含量降至61.87％.%CT Through the analysis of surface topography, phase composition and cobalt content of the alloy, the formation of Co-capping during sintering of ultrafine WC-10%Co cemented carbide was studied. The results indicate that when sintered under 1 100 °C for 50 minutes, the surface of the alloy appears typical neck and porosity spheroidization morphology, and the cobalt content of the surface is 54.12%. After 10 minutes sintering under 1 250 °C, 1 300