中文摘要：

采用脉冲电沉积方法在Q235钢表面制备Ni-P／纳米A1203复合镀层，对复合镀层进行200～400℃的热处理。利用x射线衍射仪分析复合镀层的组织结构，用电化学极化曲线和扫描电镜（SEM）研究复合镀层在3．5％NaCl和10％H2S04溶液中的腐蚀行为。结果表明，纳米A1203颗粒推迟热处理过程中复合镀层内Ni3P相的析出，其晶化温度高于Ni-P合金镀层；镀态及300℃热处理复合镀层在两种腐蚀介质中均表现出优异的耐腐蚀性能，400℃热处理复合镀层的耐腐蚀性能下降，镀层表面发生点蚀。

英文摘要：

The Ni-P/nano-A1203 composite coating on Q235 steel was prepared by pulse electroplating, the composite coatings were heat-treated at temperature of 200-400 ℃. The microstructure of the composite coatings was identified by X-ray diffraction, the corrosion behavior of the composite coatings in 3.5% NaC1 and 10% H2SO4 solutions was studied by the linear polarization measurements and scanning electron microscope （SEM）. The results show that nano-A1203 particles retard precipitating of Ni3P phase in composite coating, the crystallization temperature of the composite coating is higher than that of Ni-P alloy coating. The as-deposited and after 300℃ heat-treated composite coatings revealed better corrosion resistance in two corrosive solutions. The corrosion resistance of after 400℃ heat-treated composite coatings decreased. The corrosion behavior is pitting corrosion.