Microstructure and Sliding Wear Behaviour of Ni(Cr)-TiB2 Coatings Deposited by HVOF Spraying of SHS Powders
来源期刊：材料热处理学报2004年第5期
论文作者：Zohreh Sadeghian Behnam Lotfi
关键词：SHS; thermal spraying; wear; cermet; boride;
摘 要：This work reports research concerning the microstructure and sliding wear behaviour of cermet coatings deposited by high velocity oxy-fuel (HVOF) spraying. Two cermets were prepared with the following target compositions namely, Ni (Cr)-65 wt.% TiB2 and Ni (Cr)-40 wt.% TiB2. Coating microstructures were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD), whilst microhardness and sliding wear tests were performed on the coatings to evaluate their performance. The HVOF sprayed deposits had layered, splat-like morphologies typical of thermally sprayed cermets. Coatings consisted primarily of TiB2 particles in a nickel-based binder phase. Other minor peaks in the XRD patterns belong to TiB, Ni2B, NiTiO3 and Ti2O3. The coatings exhibit an amorphous halo in the diffraction pattern between 2θ. values of 40° and 50°. Sliding wear behaviour was examined using a conventional ball-on-disc apparatus. A sintered ceramic ball (Al2O3) was employed as the counterface. The Ni (Ct)-65 wt.% TiB2 coating had a lower wear rate than Ni (Cr)-40 wt.% TiB2 coating. This may be related to the larger sizes of borides. Wear scar morphologies, on both coatings were examined by using SEM and EDAX detecting in order to establish the wear mechanism. Wear is proposed to proceed by subsurface cracking in these coatings.
Zohreh Sadeghian1，Behnam Lotfi2
(1.Department of MaterialsScience and Engineering, Isfahan University of Technology, Isfahan, Iran;
2.Faculty of Engineering, Department of Materials Engineering, Shahrecord University, Shahrecord, Iran)
摘要:This work reports research concerning the microstructure and sliding wear behaviour of cermet coatings deposited by high velocity oxy-fuel (HVOF) spraying. Two cermets were prepared with the following target compositions namely, Ni (Cr)-65 wt.% TiB2 and Ni (Cr)-40 wt.% TiB2. Coating microstructures were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD), whilst microhardness and sliding wear tests were performed on the coatings to evaluate their performance. The HVOF sprayed deposits had layered, splat-like morphologies typical of thermally sprayed cermets. Coatings consisted primarily of TiB2 particles in a nickel-based binder phase. Other minor peaks in the XRD patterns belong to TiB, Ni2B, NiTiO3 and Ti2O3. The coatings exhibit an amorphous halo in the diffraction pattern between 2θ. values of 40° and 50°. Sliding wear behaviour was examined using a conventional ball-on-disc apparatus. A sintered ceramic ball (Al2O3) was employed as the counterface. The Ni (Ct)-65 wt.% TiB2 coating had a lower wear rate than Ni (Cr)-40 wt.% TiB2 coating. This may be related to the larger sizes of borides. Wear scar morphologies, on both coatings were examined by using SEM and EDAX detecting in order to establish the wear mechanism. Wear is proposed to proceed by subsurface cracking in these coatings.
关键词:SHS; thermal spraying; wear; cermet; boride;
【全文内容正在添加中】
