Research On Formation Factors And Performance Of Wear-resistant Coatings For Aluminum

As lightweight materials used in automobile technology, aluminum alloy have played an important role in energy saving and emission reduction areas. However, poor wear-resistance of aluminum alloy limited its further using in automobiles, mould, precision machinery, aviation, transport and other application areas. In order to improve its wear-resistance performance, this article chose one of aluminum alloys that have moderate tensile strength, 6061-T651, as the research object; sintered WC-17Co powder as coating material used in this paper attempting to prepare wear-resistance coatings. The purpose of this research was to deposit superior WC coatings on aluminum alloy and studied proper parameters used in preparing these coatings, and found out interaction among various parameters, the composition of phase in coatings and possibility of NiAl coatings used to upgrade the properties of WC coatings.In the paper, using environmental scanning electron microscopy and energy dispersive spectroscopy analyzed organization and structure of coatings in cross-section position. The composition of coatings was studied using EDS equipment. The micro-hardness and its distribution of coatings were studied using hardness tester, and the bonding strength of the coating were tested on electronic universal testing machine, and the porosity of coatings was measured by the specialized software.The results showed that: the optimal bonding strength was up to 42.42MPa and the porosity of coatings was about 5%. The best parameters was obtained in study, and its result was as follows: the feed powder current was 20μA, the kerosene volume was 14 L / h, the spraying distance was 280mm, the oxygen flow was 22m3/ h and the nitrogen flow was 15m3/ h. Through analyzing the result of different parameters, the author found that the kerosene volume had strong influence on bonding strength and porosity of coatings. When the spray distance was 320mm, the flatten and melt state of particles was the best and longer spray distance would reduced the bonding strength and increased porosity. The spectrum analysis results showed that the composition of coating realized mutual diffusion of element, and adding nitrogen did not damage the coating composition. Due to its light-weight, NiAl powder was hard to be accelerated in supersonic flame flow. Consideration the hardness of NiAl coating was between aluminum and WC coatings, NiAl coatings as buffer layer could improve the service life of wear-resistant coatings.