Effect of Heat Treatment on Microstructure and Corrosion Resistance of Ni-P/BN(h) Composite Coatings
The Ni-P/ BN(h) composite coatings were prepared by pulse electroplating,and were heat treated at temperature of 200～400°C.The microstructure of the composite coatings was identified by X-ray diffraction,the corrosion behavior of the composite coatings in 3.5%NaCl and 10%H2SO4 solutions was investigated by the linear polarization measurements and scanning electron microscope (SEM).The results show that the as-deposited is an amorphous structure,the precipitated phases are Ni12P5 and Ni5P2 metastable state phases when heat treatment temperature is below 300°C,the precipitated phases is Ni3P stable state phase heat-treated at 400°C，the composite coating was crystallized in great degree.Both the as-deposited and heat treated composite coatings revealed best corrosion resistance in 3.5%NaCl and 10%H2SO4 solutions.
Zhong Cao, Xueqiang Cao, Lixian Sun, Yinghe He
C. Z. Peng et al., "Effect of Heat Treatment on Microstructure and Corrosion Resistance of Ni-P/BN(h) Composite Coatings", Advanced Materials Research, Vols. 239-242, pp. 3362-3366, 2011