Influences of carbon addition on in situ synthesis of WC-Co composite powder and properties of tungsten carbides coatings
The ultrafine WC-Co composite powder was rapidly synthesized through in situ reduction and carburization reactions using pre-treated tungsten oxide, cobalt oxide and carbon black as raw materials, which was a novel technique originally developed in our group and at present has achieved batch production. Using the as-synthesized composite powder, the granulation processing was then carried out to prepare the ultrafine structured thermal spraying feedstock powder. The influences of the carbon addition on the phase constitution, the microstructure and the mechanical properties of as-sprayed ultrafine-structured WC-Co coatings by high velocity oxy-fuel (HVOF) were investigated. The results show that the ultrafine-structured WC-Co thermal spraying feedstock with pure phases can be prepared by controlling the carbon addition in the initial stage. Moreover, small amounts of free carbon in the feedstock can effectively inhibit the dissolution of W in cobalt which decreases the hardness of the Co matrix and thus the coating. In contrast, the elastic modulus firstly reduces sharply and then almost remains constant with the increase of free carbon concentration in the feedstock. The wear resistance of the coating is enhanced by the tough Co binder phase with less W and C. The studies demonstrate that the developed techniques for composite powder and thermally sprayed coating are very promising to be applied in industries to produce ultrafine structured cemented carbides coatings with high performance.
WC-Co composite powder in situ synthesis carbon addition free carbon ultrafine structured coating
Haibin Wang Xiaoyan Song Xuemei Liu Yao Wang Yang Gao Chongbin Wei Yuxi Li Wuxi Zhou
College of Materials Science and Engineering, Key Lab of Advanced Functional Materials, Education Mi Zigong Tungsten Carbide Co., Ltd. Zigong 643000,Sichuan,China
国际会议
北京
英文
555-561
2012-10-23（万方平台首次上网日期，不代表论文的发表时间）