Study on Microstructure and Properties for Co-rich Layers Cemented Carbides by Surface Nitriding Treatment
GONG Manfeng1, SUI Guangzhou1, LIAN Haishan1, LI Mingsheng1,
MO Deyun1, CHEN Jian2, WU Shanghua2
1 Institute of Mechatronic Engineering, Lingnan Normal University, Zhanjiang 524048; 2 College of Mechatronic Engineering, Guangdong University of Technology, Guangzhou 510220
Abstract: The Co-rich layers and Ti-rich hard phase-layers on cemented carbides were prepared by a two-step sintering technology, respectively. The microstructure, sintering phases and mechanical properties of cemented carbides before and after nitriding treatment were studied. The ~20 μm-thick Co-rich layers were obtained on the surface of specimen under vacuum sintering condition, and no cubic carbide phase was contained in the Co-rich layers. The surfaces of specimen appear a kind of hill topography and own bright silver metal luster which were confirmed by microstructure morphology analysis. It can be used to repair the micro-defects, e.g. micro-cracks or micro-holes, on the surface of specimens, improve the toughness of cemented carbides surface, and enhance the interfacial bonding strength between the coating and the substrate. The fine grain ~1 μm-thick Ti-rich hard phase layers could be prepared in situ on the specimen surface by nitridation. The Ti-rich hard phase layers appear gold or brown color and a relatively smooth surface by microstructure analysis. Through comparison and analysis, it could be concluded that though the densities of specimens are decreased as a result of nitridation treatment, but simultaneously some properties can be significantly improved, such as fine grain size distribution and favorable surface micro-strain in the Ti-rich hard phase, which can promote surface hardness with remote toughness loss, and also effectively improve wear resistance and lifetime of cemented carbide tools.
弓满锋, 隋广洲, 连海山, 李明圣, 莫德云, 陈健, 伍尚华. 富Co-layers硬质合金表面渗氮处理微观结构和性能研究*[J]. 《材料导报》期刊社, 2017, 31(8): 56-61.
GONG Manfeng, SUI Guangzhou, LIAN Haishan, LI Mingsheng, MO Deyun, CHEN Jian, WU Shanghua. Study on Microstructure and Properties for Co-rich Layers Cemented Carbides by Surface Nitriding Treatment. Materials Reports, 2017, 31(8): 56-61.
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2017, Vol. 31 
