| To make the equipments meet the severe service requirement, the electro-brush plating technology has been developed from the single coating, to the composite coating, and to the nano-particle composite coating. The nano-particle composite electro-brush plating technology is used for preparing the composite coating with the distinctive anti-wear performance.Nano-particles were dispersed into the nickel brush-plating electrolyte by using ultrasonic, mechanical, surfactant and high energy mechanical and chemical techniques, for the purpose of preparing the nano-particle composite electro-brush electrolyte. Characteristics of the nano-particles in the composite elctrolytes such as size distribution and Zeta potential were tested as well as that of composite electrolytes such as pH value and conductance. Microstructure of nano-particle composite coatings was studied through TEM, SEM and EDS, and deposition mechanism of the composite coatings was investigated as well as their reinforcement mechanism. Contact fatigue resistance of composite coatings was studied as well as anti-fretting wear from room temperature to 500℃. The main results gained are as follows:A high energy mechanical and chemical technique was obtained which could effectively prepare nano-particle composite electrolytes based on the nickel electrolyte. Comparing with the general ultrasonic, mechanical and surfactant techniques, the high energy mechanical and chemical technique could reduce the surface energy of nano-particles and cause them to be soaked by the electrolyte. So a double electricity film was formed on the surface of nano-particles, taking on electronegative as a whole and could play a role as the static potential obstruction, and meanwhile the surfactant could play a role as the space obstruction. Therefore, conglomeration of nano-particles was in a light degree, uniformly dispersed in the composite electrolyte and properties of the composite electrolyte were steady for a long time.The preparation process of the composite coatings was optimized as well as the nano-particle content in the electrolyte. When the composite coatings were prepared by one-step activation process and from the electrolyte with the 20 g/L nano-particles content prepared by the high energy mechanical and chemical technique, the composite coatings had uniform microstructure and the nano-particle content of 1.5-3.5%. The nano-particles evenly dispersed in the coatings and adhere compactly to the nickelmatrix Micro-hardness of the composite coatings could reach to 700 Hv, over 1.5 times of that of the nickel coating.Micro-structure of nano-particles composite coatings was analyzed by means of SEM and TEM. Reinforcement mechanisms of composite coatings were as follows: fine crystals, high density dislocations and second phase particles. Nickel crystal grains in the composite coating were about at the size of 50 nm and the surface morphology of the coatings was fine, compact and smooth, and their structure was layer-like which thickness was about 50 nm. There were large amounts of dislocations and twin grains in the composite coating. The distribution of nano-particles was uniform and no agglomeration, and also the nano-particles adhered to nickel compactly. The nano-particle composite electro-brush plating deposited selectively the nano-particles which size were less than the thickness of the monolayer and therefore made the size of nano-particles in the coatings smaller.By analyzing the cross-section microstructure and surface morphology of composite coatings, it was elucidated that the deposition process of composite coatings was formed by continuous three stages as following: uniform growth, formation of little convex body and formation of dentritic crystals. According to the denotation of Zeta potential of the surface of nano-particles, it was clear that the co-deposition mechanism of nano-particles with nickel was mainly mechanics.Micro-structure of the contact fatigue deformation layer showed that in the process of contact fatigue, nano-pa...
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