The purpose of the paper is improving the corrosion-resistance and rigidity of the casts. In this study,a TiO2 film is coated on the cast surface by the sol-gel method before the chemical depositon of Ni-P is conducted. The results show that the TiO2 coating can effectively reduce the cavity density on the cast surface, and avoid the disadvantages of the direct Ni-P deposition method that is likely to produce pinholes. Compared with the existing methods of cast surface processing, the present technique is charaterized by the combination of the excellent performance of the TiO2 film and the environment-protection of Ni-P chemical deposition method. This technique not only improves the corrosion-resistance of the cast, but also increases the deposition rate considerably. On the premise of no extra cost, it economizes the energy resource.%为了提高铸件的耐腐蚀性及硬度,采用溶胶-凝胶法先在铸件表面涂覆一层TiO2薄膜,再对铸件进行化学镀Ni-P处理.研究表明,TiO2涂层可以有效减小铸件表面的孔隙率,弥补了Ni-P镀层直接覆盖在铸件表面易产生针孔的缺陷.与现有的铸件表面处理方法相比,改善了铸件的耐腐蚀性,而且较大地提高了沉积速率.在不增加成本的情况下,节约了能源.
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