Manufacture of the Ultrafine Grain WC/Co Cemented Carbides by Combined Sintering Processing

A new kind of sintering process, combined sintering process. i.e. vacuum sintering plus hot isolate pressure sintering (HIP), was introduced for producing ultrafine WC-10% Co (mass fraction. so as the follows) cemented carbides. The effects of some processing parameters on the microstructure and mechanical properties of the obtained cemented carbides were studied. The results show that the rapid shrinkage and the pronounced densification of tile cemented carbides took place during the vacuum sintering stage, which is intinaately correlated with the local liquid sintering occurred during this earl} sintering stage for the high surface activity of ultrafine WC-Co powder. The way of high pressure imposing. isothermal treatment cycle during ac.acuum sintering and HIP sintering stage directly influence the densitication of compacts and the mechanical properties of the produced WC-10%Co cemented carbides.

超细纳米硬质合金及晶粒长大抑制剂的研究

超细 纳米WC -Co硬质合金由于其优越的性能而获得更加广泛的应用 ,从而成为近年来各国政府研究学者及厂矿企业十分关注的热门话题。本文综述了国内外在超细 纳米硬质合金及晶粒长大抑制剂方面的研究进展。重点介绍了超细 纳米WC -Co复合粉末的制备技术和新的烧结工艺以及晶粒长大抑制剂的种类、添加方式和作用机理。

新型直接碳化法制备超细WC粉及其烧结体的结构与性能

本文对直接碳化法制备超细WC粉进行了研究，以三氧化钨和炭黑为原料，制备方法为：首先湿磨包含炭黑与三氧化钨的混合物，其中碳源数量大于热力学反应温度下制备WC所需的化学计量；湿磨好的浆料经干燥后，在非还原气氛N2中，于1000～1100℃直接碳化得到包含完全渗碳的碳化钨和过量碳的中间产物；之后调节其碳含量至（6．13±0．05）％。对最终所得碳化钨粉进行粒度及碳、氧含量分析，并以其为原料，按YG6配钴，添加晶粒长大抑制剂，用真空烧结法制备出了显微结构均匀、矫顽磁力≥39．2kA／m、平均晶粒度为0．4μm左右的超细硬质合金。