目的 提高金属材料在高温、高压、高氯离子腐蚀环境下的耐蚀性。方法 采用化学镀法在L245表面制备Ni-W-P镀层和Ni-W-P-nSiO2复合镀层，利用X射线衍射仪（XRD）、扫描电镜（SEM）、显微硬度仪及贴滤纸法对镀层结构、形貌、硬度及孔隙率进行表征。采用高温高压腐釜模拟现场工况进行72 h均匀腐蚀试验，设置温度为150 ℃、压力为35 MPa，利用失重法计算腐蚀速率。结果 Ni-W-P镀层和Ni-W-P-nSiO2复合镀层均为非晶态结构，扫描电镜形貌观察表明三种镀层表面均为胞状组织，吸附在基体表面的纳米二氧化硅作为形核核心，使Ni-W-P-nSiO2复合镀层的组织更细小。添加纳米二氧化硅的复合镀层的孔隙率从添加前的1.24减小到0.83。磁力搅拌和超声辅助Ni-W-P-nSiO2复合镀层的硬度分别为491.6HV和421.7HV，较Ni-W-P镀层的384.5HV分别增加了107.1和37.2HV；磁力搅拌及超声辅助Ni-W-P-nSiO2复合镀层的腐蚀速率分别为0.0552 mm/a和0.0371 mm/a，是Ni-W-P镀层腐蚀速率（0.1075 mm/a）的1/2和1/3。腐蚀后表面成分分析表明，超声辅助Ni-W-P-nSiO2复合镀层的表面腐蚀产物为Ni3S2，能有效保护基体。结论 超声辅助Ni-W-P-nSiO2复合镀层的耐蚀性相比Ni-W-P镀层显著提高。

The work aims to improve corrosion resistance of metal materials in high temperature, high pressure and high chloride corrosion environment. Ni-W-P alloy coating and Ni-W-P-nSiO2 composite coatings were prepared on L245 steel by chemical plating. Structure, morphology, hardness and porosity of the coatings were characterized with X ray diffractometer (XRD), scanning electron microscope (SEM), microhardness tester and in filter paper method. 72 h uniform corrosion tests were carried out by simulating field conditions in a high temperature autoclave at 150 ℃, 35 MPa, and corrosion rate was calculated in weight loss method. The Ni-W-P coating and Ni-W-P-nSiO2 composite coatings were all amorphous structures. SEM observation showed that the surface of the three coatings were cellular, and the nano silica adsorbed on the surface of the substrate make the microstructure of Ni-W-P-nSiO2 composite coating smaller as a nucleation core. Porosity of the composite coatings containing nSiO2 decreased from 1.24 to 0.83. Hardness of magnetic stirring and ultrasound-assisted Ni-W-P-nSiO2 composite coatings was 491.6HV and 421.7HV, respectively, which was 107.1HV and 37.2HV higher than that of Ni-W-P coating (384.5HV), respectively. The corrosion rates of magnetic stirring and ultrasonic assisted Ni-W-P-nSiO2 composite coatings were 0.0552 mm/a and 0.0371 mm/a respectively, 1/2 and 1/3 of 0.1075 mm/a of Ni-W-P coating. Surface composition analysis after corrosion indicated that the surface corrosion product of ultrasonic-assisted Ni-W-P-nSiO2 composite coatings was Ni3S2 film, which could effectively protect the substrate. Compared with Ni-W-P alloy coating, the corrosion resistance of ultrasound-assisted Ni-W-P-nSiO2 composite coatings is obviously improved.