Study on Properties of 45 Carbon Steel Ni-P Electroless Plating Reinforced by Si₃N₄-Al₂O₃ Particle Based on Response Surface Method.

The effects of the different content of Si³N⁴ particles and Al²O³ particles in the plating solution and the different ratios on the wear resistance, microhardness, corrosion resistance and other properties of the coating were analyzed by using the centre composite surface design of response surface method (RSM). Meanwhile the phase composition, appearance, microhardness, friction coefficient and corrosion resistance of the electroless coating were tested. The results show that the addition of Al²O³ and Si³N⁴ particles in the bath can increase the microhardness of the electroless composite coating. In a certain range, the increase of Al²O³ or Si³N⁴ particles in the bath causes the microhardness of the coating to increase, but the excessive addition of particles makes microhardness decrease; the electroless coating with two particles added will have a low coefficient of friction; and with respect to corrosion resistance, the addition of Al²O³ or Si³N⁴ particles will increase the corrosion resistance of the coating. Overall, the electroless coating with the Al²O³ content of 16 g/L and the Si³N⁴ content of 12.63 g/L has the better comprehensive performance.