Study On The Preparation And Formation Mechanism Of A New Wearable Composite Coating

As a kind of excellent treatment technology with simple technics, homogeneous and fine coatings, electroless composite plating is getting studied and applied widely. The special performance of nanometer material makes it have much more intensity and hardness than the common, and become one of the hotspots in material field. Combining the two technology above, this dissertation studied the preparation of electroless multi-composite coating compounded with nano Al₂O₃ powder and PTFE.This paper studied the influence of bath temperature and pH value on the stability of bath, deposition rate and the ratio of P in the coating; and found out their proper process conditions. The influence of the concentration and dimension of the powder added in bath on the ratio of particles in coatings and the properties of coatings was also studied; and the value of these parameters were determined by orthogonal test.The effects of various dispersing methods on the properties of coatings were studied in the paper. According to the comparison among the different effects of dispersing methods and their intensity on the properties of coatings, and the research of the categories and concentration of the surfactants in bath, the preferable value of these parameters was found out.The microstructure, microhardness, wear resistance capability, etc. of coatings were analysed by XRD, SEM and other instruments. Moreover, the binding strength and corrosion resistance capability of coatings, and the influence of heat treatment on the microstructure and properties of coatings were also studied. The results of the comparison between the composite coating Ni-P-PTFE-Al₂O₃ and Ni-P, M-P-Al₂O₃ (μ m), Ni-P- Al₂O₃(nm), Ni-P-PTFE indicated that the integrated performance was superior to Ni-P and other composite coatings compounded with single particle.In addition, the paper made a preliminary discussion on the mechanism of electroless composite codeposition and stability of bath; and analysed the dispersing mechanism of the particles in the bath. Meanwhile the common law of the deposition rate was studied on the dynamic aspects.