氧化‐还原碳化法回收再生高性能硬质合金的研究

Recycling of Cemented Carbides by Oxidation and Reduction-Carbonization Reactions and Preparation of High Performance Hard Metals

以废旧WC-Co硬质合金为原料,采用氧化和原位还原碳化的短流程方法合成再生WC-Co复合粉末,随后对再生复合粉低压烧结得到再生硬质合金。利用XRD、SEM和TEM等对再生复合粉和再生硬质合金的物相和显微组织形貌进行观察和分析,系统研究了原料粉末中配碳量对再生复合粉和再生合金的物相组成和力学性能的影响。配碳量为16.60%时制备的再生WC-16%Co(质量分数,下同)硬质合金的断裂韧性为24.80 MPa·m1/2、横向断裂强度达到3860MPa,并且分析了再生硬质合金的显微组织与性能之间的关系。

The wasted cemented carbides were used as the raw materials and subjected to oxidation, reduction and carbonization reactions to synthesize the WC-Co composite powder. Then the recycled composite powder was sintered to prepare the cemented carbide bulk by the process of sinter-HIP. The phase composition and microstrueture of the recycled composite powder and sintered bulk were investigated by XRD, SEM and TEM. The effects of carbon addition in the oxide powders on the phase composition and mechanical properties of the recycled composite powder and the sintered bulk were investigated. By the present method, for the carbon addition of 16.60%, the high-performance cemented carbide bulk was obtained, with fracture toughness of 24.80 MPa.m1/2 and transverse rupture strength of 3860 MPa. The relationship between microstructure and properties of the sintered bulk was investigated.