Study on the Structures and Properties of Ni-W-B-CeO2 Composite Coatings Prepared by Pulse Electrodeposition
来源期刊：JOURNAL OF RARE EARTHS2007年增刊第1期
论文作者：Wang Junli Guo Zhongcheng Wang Hua Xu Ruidong
Key words：pulse electrodeposition; composite coatings; deposition rate; microhardness; microstruetures; rare earths;
Abstract: The aim of this research is to pulse co-deposit nano-CeO2 particles into Ni-W-B alloy coatings in order to improve the surface properties. The influence of pulse frequency and duty circle on deposition rate, microhardness and microstructures, and the influence of heat treatment temperature on phase structures, microhardness and abrasivity of Ni-W-B-CeO2 composite coatings were investigated. The results indicated that the pulse co-deposition of nickel, tungsten, boron and nano-CeO2 particle from the bath which nano-CeO2 particle was suspended by high speed mechanical stirring led to the Ni-W-B-CeO2 composite coatings, possessing better microhardness and abrasion resistance when heat-treated at 400℃ for 1h. The microhardness as-deposited with 636Hz and the deposition rate with 0.0281mm·h-1 was the highest at pulse frequency with 1000Hz and pulse duty circle with 10%. Microstructures analysis displays that decreasing pulse duty cycle leads to refinement in grain structures and the improvement of microstructures. X-ray diffraction shows that the composite coating as-deposited was mainly in the amorphous state and partially crystallized, but when heat treated at 400℃, the crystallization trend was strenthened further.
Wang Junli1，Guo Zhongcheng2，Wang Hua2，Xu Ruidong2
(1.Research Center for Analysis and Measurement, Kunming University of Science and Technology, Kunming 650093, China;
2.Faculty of Materials and Metallurgical Engineering, Kunming University of Science and Technology, Kunming 650093, China)
Abstract:The aim of this research is to pulse co-deposit nano-CeO2 particles into Ni-W-B alloy coatings in order to improve the surface properties. The influence of pulse frequency and duty circle on deposition rate, microhardness and microstructures, and the influence of heat treatment temperature on phase structures, microhardness and abrasivity of Ni-W-B-CeO2 composite coatings were investigated. The results indicated that the pulse co-deposition of nickel, tungsten, boron and nano-CeO2 particle from the bath which nano-CeO2 particle was suspended by high speed mechanical stirring led to the Ni-W-B-CeO2 composite coatings, possessing better microhardness and abrasion resistance when heat-treated at 400℃ for 1h. The microhardness as-deposited with 636Hz and the deposition rate with 0.0281mm·h-1 was the highest at pulse frequency with 1000Hz and pulse duty circle with 10%. Microstructures analysis displays that decreasing pulse duty cycle leads to refinement in grain structures and the improvement of microstructures. X-ray diffraction shows that the composite coating as-deposited was mainly in the amorphous state and partially crystallized, but when heat treated at 400℃, the crystallization trend was strenthened further.
Key words:pulse electrodeposition; composite coatings; deposition rate; microhardness; microstruetures; rare earths;
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