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论文类型：期刊论文

发表时间：2014-06-01

发表刊物：INTERNATIONAL JOURNAL OF ELECTROCHEMICAL SCIENCE

收录刊物：SCIE、Scopus

卷号：9

期号：6

页面范围：2882-2895

ISSN号：1452-3981

关键字：Trivalent chromium composite coatings; Carbon nanotubes; Direct current deposition; Crack-bridging bonding; Wear resistance

摘要：The trivalent chromium composite coatings with multiwall carbon nanotubes (MWCNTs) were fabricated by the direct current deposition under an ultrasonic agitation on the pure aluminum substrate using a zincate interlayer. Compared with the trivalent chromium coatings, the chromium composite coatings about 35 mu m thick with MWCNTs have the similar amorphous microstructure with a limited crystallization. The horizontal stymie of carbon nanotubes between the chromium grains was mainly located in the chromium composite coatings. A slightly increased microhardness to HV1 (N) 9.2-9.8 GPa was obtained from HV1 N 8.0-8.3 GPa of the pure chromium coatings. During the tribological test on a ball-on-disc tribometer against an Si3N4 ceramic courterface under a normal load of 0.5-2 N, the similar friction coefficient of the two trivalent chromium coatings changed in 0.60-0.47, which was dependent on the applied normal load. However, the significant increase in wear resistance of the chromium composite coatings with MWCNTs, relative to that of the pure chromium coatings, was found with the specific wear rate decreased by about 30-40 % under the applied normal load. A crack-bridging bonding model was proposed to explore the improvement mechanism in wear resistance by the carbon nanotubes as reinforced nanometer fiber in the trivalent chromium composite coatings.