In this paper,three kinds of cermet particles with different binder phase and content,namely WC-12Co,WC-17Co and Cr3C2-25NiCr were deposited on the Q235 low carbon steel and WC-12Co coating substrates to investigate the effect of binder phase content and substrate hardness on deposition behavior of cermet particle during cold spraying.The morphology of the deposited particles was examined by scanning electron microscopy(SEM)from the particle surface and cross-sections.It was found that with increasing substrate hardness,the deposition behavior of cermet particles transformed from completely embedding into substrate to partially flattening and even rebounding.Varying the Co content from 12 wt%to 17 wt% influenced significantly the deposition deformation behavior of the WC-Co particles,the higher Co content brought about a fuller flattening of WC-Co particles.However,Cr3C2-25NiCr particle exhibited the relatively lower flattening ratio and significant rebounding of Cr3C2 even with the highest binder phase content,which may be attributed to the bigger Cr3C2 size and weak bonding between Cr3C2 and NiCr.
Wang HongtaoJi GangchangChen XiaoChen QinyuBai Xiaobo
A dense Al/SiCp composite coating with high volume fraction(60%)of nano SiCp reinforcement was fabricated by cold spraying of ball-milled Al-60SiCp composite powder.The morphologies evolution of the Al-60SiCp composite powder during ball milling and the microstructure and microhardness of the cold-sprayed Al-60SiCp composite coating were investigated.The results show that Al particles undergone fracture deformation and nano SiC particles are uniformly distributed in soft Al matrix after ball milling.A dense Al-60SiCp composite coating can be fabricated by cold spraying of ball milled composite powder.Nano SiC particles in the cold-sprayed Al-60SiCp composites coating exhibit a reasonably uniform distribution.The Hv0.5 microhardness of the Al-60SiCp composite coating is reached up to(5.30±0.53)GPa due to the enhancement of SiC particles,compared to(0.34±0.03)GPa for the pure Al bulk.
Wang HongtaoJi GangchangChen XiaoBai XiaoboChen Qinyu
