Study On Preparation And Properties Of N-Al₂O₃/Ni Composite Brush Plated Coatings

Electro-brush plating is an important strengthening and repairing technology of surface engineering, it is favored by industrial production with its simple operation, high deposition speed, less pollution characteristics, and made great progress in the process, characterization, performance testing with deep research. In addition, as the introduction of increasingly mature nanotechnology, further improve the performance of the coatings, various types of high performance composite coatings to a great extent meet the producing and living needs.In this article, confected well-dispersed, stable Al2O3 composite electroplating solution, then designed orthogonal test table with voltage, Al2O3 concentration and the initial temperature of the bath to be the parameters, obtained the coating on stainless steel substrate with impulse current. The handheld roughness meter, micro-hardness tester, metallurgical microscope, scanning electron microscope (SEM) and X-ray diffraction spectrometer were used to test the roughness, hardness, morphology, microstructure and elementary content of composite coatings. Detected the bonding strength of the coatings qualitatively, analyzed the composite coatings’friction and wear properties by method of friction and wear test. Determined the optimal test program according to the result, then discussed and analyzed.The results of the test show that nano particles dispersed in the coating acted as barriers so that the cracks became thinner and shorter, they also reduced surface defects, refined grains. Therefore, the surface roughness became smaller, and the coatings’ hardness significantly increased, but the enhancing effect vary with different parameters, when the voltage is 11V, the Al2O3 concentration is 15g/L, initial bath temperature of the bath is 50℃, the hardness value reaches the maximum. There weren’t peeling, cracking, flaking and other drawbacks, the bonding strength of the coatings were good. By the detection of friction and wear test, the coefficient of composite coatings slightly decreased compared to the general coatings, abrasion resistance significantly strengthened, with less adhesive wear phenomenon, significantly reduced the wear loss, declined the most with a 48.3% drop compared to the general coatings.