(沈阳大学 材料科学与工程系, 沈阳110044)
摘 要: 采用动电位阳极极化法对17%SiCp/2024Al基复合材料及其基体合金在3.5%NaCl水溶液中的耐蚀性进行了研究。 结果表明： SiC颗粒的加入并不影响SiCp/2024Al基复合材料的点蚀敏感性， 但与基体相比， 其耐蚀性有所下降。 对极化后和长期浸泡试样的腐蚀形貌观察发现： 与基体相比， SiCp/2024Al基复合材料表面上的蚀孔数量相对较多， 蚀孔尺寸稍小， 大小分布不均匀； 最大蚀孔较深， 并有严重的裂缝腐蚀； 裂缝腐蚀的存在会使SiCp/2024Al基复合材料的点蚀抗力明显降低。 能谱分析表明： SiCp/2024Al基复合材料的腐蚀机制为富Cu阴极相与贫Cu阳极相间的电偶腐蚀， 另外， SiC与Al间也存在电偶腐蚀倾向。
关键字: 2024Al； 金属基复合材料； 点蚀形貌
metal matrix composite
（ Department of Materials Science and Engineering,
Shenyang University, Shenyang 110044, China）
Abstract: The corrosion resistance of 17% SiCp/2024Al metal matrix composite (MMC) and 2024Al in 3.5% NaCl solution was investigated by potentiodynamic polarization. The results show that pitting susceptibility is about the same for SiCp/2024Al MMC and its matrix alloy. The corrosion resistance for SiCp/2024Al MMC is lower than that for the matrix. Pit morphology was observed with scanning electric microscope. After anodic polarisation in 3.5%NaCl solution, pits on SiCp/2024Al MMC are more numerous, a little smaller and non-uniform in size compared with that on 2024Al, and severe crevice corrosion is only found at the bottom of pit on SiCp/2024Al MMC. The biggest pits on the long-term immersion SiCp/2024Al MMC are slightly deeper than that on 2024Al, and crevice corrosion is only found on SiCp/2024Al MMC. The crevice corrosion can make SiCp/2024Al MMC possess lower pitting corrosion resistance. The corrosion mechanism of SiCp/2024Al MMC is galvanic corrosion between the phase rich in Cu and the matrix, as well as between the SiC and the matrix.
Key words: 2024Al; metal matrix composite; pit morphology
