Z.C. Guo
,
X.Y. Zhu
金属学报(英文版)
The effects of pulse frequency f and duty cycle r on the deposition rate, composition, morphology, and hardness of pulse electrodeposited RE (rare earth)-Ni-W-P-SiC composite coatings have been studied. The results indicate that pulse current can improve the deposition rate of RE-Ni-W-P-SiC composite coatings; W, P, and SiC contents in the coating decrease with the increase of pulse frequency and reach the lowest value at f = 33Hz, whereas the RE content in the composite coatings increases with increasing
pulse frequency. SiC content decreases with the increase of duty cycle, W content reaches the lowest value, and P content reaches the highest value at r = 0.4; pulse current and RE can lead to smaller size of the crystalline grains; however, the effects of different pulse frequency and duty cycle on the morphologies of RE-Ni-W-P-SiC composite coatings are not obvious. The hardness of
RE-Ni-W-P-SiC composite coatings is the highest when the duty cycle is at 0.6 and 0.8 and pulse frequency is at 50Hz. At the same pulse frequency, the hardness of RE-Ni-W-P-SiC composite coatings at r = 0.8 is higher than that at r = 0.6.
关键词:
pulse frequency
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null
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Z.C. Guo
,
X.Y. Zhu
,
R.D. Xu
金属学报(英文版)
Cathodic deposition current density of the composite coatings increases when SiC par-ticles and rare earth (RE) were added in the bath, which is profitable for Ni- W-P alloyto deposit in the cathod, forming Ni-W-P-SiC and RE-Ni-W-P-SiC composite coat-ings. On the contrary, the addition of PTFE in the bath decreases cathodic depositioncurrent density of the coatings. The current density increases a little when the amountof RE is 7-9g/l; however, the current density increases greatly when the amount ofRE is increased to 11-13g/l. But if the amount of RE is raised further, the currentdensity decreases. Hardness and wear resistance of RE-Ni-W-P-SiC composite coat-ing have been studied, and the results show that the hardness and wear resistance ofRE-Ni-W-P-SiC composite coating increase with increasing heat treatment tempera-ture, which reach peak values at 400℃; while the hardness and wear resistance of thecoating decrease with the rise of heat treated temperature continuously.
关键词:
electrodeposition
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