(沈陽大學(xué) 材料科學(xué)與工程系, 沈陽110044)
摘 要: 采用動電位陽極極化法對17%SiCp/2024Al基復(fù)合材料及其基體合金在3.5%NaCl水溶液中的耐蝕性進行了研究。 結(jié)果表明： SiC顆粒的加入并不影響SiCp/2024Al基復(fù)合材料的點蝕敏感性， 但與基體相比， 其耐蝕性有所下降。 對極化后和長期浸泡試樣的腐蝕形貌觀察發(fā)現(xiàn)： 與基體相比， SiCp/2024Al基復(fù)合材料表面上的蝕孔數(shù)量相對較多， 蝕孔尺寸稍小， 大小分布不均勻； 最大蝕孔較深， 并有嚴重的裂縫腐蝕； 裂縫腐蝕的存在會使SiCp/2024Al基復(fù)合材料的點蝕抗力明顯降低。 能譜分析表明： SiCp/2024Al基復(fù)合材料的腐蝕機制為富Cu陰極相與貧Cu陽極相間的電偶腐蝕， 另外， SiC與Al間也存在電偶腐蝕傾向。
關(guān)鍵字: 2024Al； 金屬基復(fù)合材料； 點蝕形貌
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
