Study On Preparation And Friction-wear Properties Of Nano Al₂O₃ Iron-based Composite Coating

Wear is one of the main failure modes of engineering materials, which has resulted in the loss of material and energy. To improve the performance and service life of the parts, it is needed to improve the surface properties of the material surface and do some strengthening to it. As a common surface strengthening and repairing process, iron plating technology plays a very important role in the repairing of damaged mechanical parts and strengthening for some special materials to the surface.Based on Dong’s alloy iron plating technology, this paper prepared a coating compositing Al2O3 nano-particles by adding a certain concentration of Al2O3 nano-particles into the bath. It got suitable plating temperature, current density and Al2O3 concentration in the composite electroplating experiment through optimization of orthogonal test. In the conditions of suitable bath temperature and current density, it prepared coatings combined with different amount of Al2O3 nano-particles by changing the concentration of Al2O3 in the solution. And it analyzed the influence of Al2O3 concentration on the coating surface and cross section morphology, micro-hardness and Al2O3 nano-particles’ content in the coatings. By friction and wear testing machine, the coating’s Tribological Performance were also detected and the nano-particles’ influence on the tribological properties of coatings were analyzed. Besides, the coating’ binding properties were detected by thermal shock experiment.The results show that there are many net cracks in the surface and line shaped cracks in the section, and the number of net cracks and line shaped cracks reduced at first and then remained unchanged with the increasing of Al2O3 particles’content in composite coatings. The hardness of composite coatings is greater than that of normal coating and the hardness of composite coatings increased at first and then decreased slightly with the increasing of Al2O3 concentration in the plating solution. The content of Al in the composite coating increased at first and then decreased slightly with the increasing of Al2O3 concentration in the plating solution. Friction and wear test results show that Al2O3 particles in composite coatings can improve its tribological performance and reduce friction coefficient and wear rate. The result of thermal shock test shows that plating coatings have good adhesion.