选择性电溶法再生WC原料中杂质Ti在硬质合金烧结过程中的作用行为

Behaviors of impurity Ti during sintering process of cemented carbides from reclaimed WC by selective electrochemistry dissolution method

采用基于选择性电溶法的再生超细WC粉末为原料,制备WC-10Co和WC-10Co-0.06La_2O_3硬质合金,研究原料中的杂质Ti,Ta和V在烧结过程中的作用行为。结果表明,杂质Ti,Ta和V同步迁移至合金烧结体表面,形成WTi(Ta,V)C_2富集相;合金中微量稀土La可促进Ti的表面迁移。Ti如果不是以固溶体型稳定化合物的形式添加,容易导致硬质合金中出现Co3W3C脱碳相和板状WC晶粒的形成。硬质合金微观组织结构的均匀性与Ti在合金中分布的均匀性密切相关。

Using reclaimed ultrafine WC powder from selective electrochemistry dissolution method as the raw material, WC-10Co and WC-10Co-0.06La203 alloys were prepared. Behaviors of impurities Ti, Ta and V during the sintering process of cemented carbides were investigated. The results show that the impurities of Ti, Ta and V in the alloys can migrate to the sinter skins. As a result, a WTi（Ta,V）C2 phase is formed on the sinter skins. The existence of rare earth La in the alloy facilitates the migration of Ti towards the sinter skins. If Ti in the raw material does not exist in the form of stable solid solution carbides, it can result in the formation of C03W3C phase and platelet WC grains. The distribution characteristic of Ti in the alloy strongly influences the homogeneity of the microstrueture.