材料期刊网

用质量损失法系统研究了不同温度(25和50℃)和不同冲刷速率(0.63-1.88 m/s)下,J4不锈钢,Ni-P和Ni-Cu-P合金镀层,及对比材料316L不锈钢在液-固两相流(20%H_2SO_4+20 g/L Al_2O_3)中的冲刷腐蚀行为.结果表明:不锈钢和镀层的抗冲刷腐蚀性能由高到低依次为镀态Ni-Cu-P,镀态Ni-P,热处理态Ni-Cu-P,316L,J4.提高两相流介质温度均使它们的冲刷腐蚀速率增大.316L不锈钢在25℃液-固两相流介质中的冲刷腐蚀速率分别为镀态Ni-Cu-P,镀态Ni-P和热处理态Ni-Cu-P镀层的8.5倍,8倍和2.6倍以上,而在50℃下分别为392倍,80倍和14.8倍以上;J4不锈钢在25和50℃液-固两相流介质中的冲刷腐蚀速率分别为316L不锈钢的28倍和13倍以上.在25和50℃,J4不锈钢分别为选择性腐蚀和均匀腐蚀,而316L不锈钢均为轻微选择性腐蚀,Ni-P和Ni-Cu-P合金镀层均为均匀腐蚀.

Components used really in industries such as mechanical, chemical, mining and petroleum industries, are often exposed to corrosive and erosive liquid-solid two-phase flow envi-ronments. These environments lead not only to high costs maintaining these components but also to shortening their service life. The behaviors of metal materials under corrosive and erosive conditions as well as the related mechanisms have been researched for several years. For reducing material failure caused by erosion-corrosion at surfaces of components, surface modification technology such as plating an Ni-P or Ni-Cu-P alloy coating with a high hardness and good corrosion resistance is an effective method. The behaviors of electroless Ni-P and Ni-Cu-P coatings, J4 and also 316L stainless steel as a contrast material were systematically investigated in liquid-solid two-phase flow (20%H_2SO_4+20 g/LAl_2O_3) by mass loss test method at different temperatures (25 and 50 ℃) and different erosion rates (0.63-1.88 m/s). The sample surface morphologies and chemical compositions were also observed by SEM. Their erosion corrosion mechanisms were also explained. The results show that their erosion corrosion resistance performance under the test conditions is in the order of plated Ni-Cu-P coating, plated Ni-P coating, plated Ni-Cu-P coating after heat treatment, 316L stainless steel and J4 stain-less steel. Their erosion corrosion resistance decreases with the increase of temperature of two-phase flow. Comparing to plated Ni-Cu-P coating, plated Ni-P coating and plated Ni-Cu-P coating afterheat treatment, stainless steel 316L has over 8.5, 8 and 2.6 times higher erosion-corrosion rate at 25 ℃ and over 392, 80 and 14.8 times higher erosion-corrosion rate at 50 ℃, respectively. The erosion-corrosion rate of J4 stainless steel is over 28 times at 25 ℃ and 13 times at 50 ℃ higher than that of 316L stainless steel, respectively. The main corrosion characteristic of J4 stainless steel is selective corrosion at 25 ℃ and uniform corrosion at 50 ℃. However, it is slightly selective corrosion for 316L stainless steel and uniform corrosion for Ni-P and Ni-Cu-P coatings. The results could be used as a useful reference for the application of electroless plating Ni-P and Ni-Cu-P coatings in erosion-corrosion environment.