摘要
研究了稀土盐硫酸铈改性磷酸–硫酸阳极氧化处理对2A50铝合金表面耐腐蚀性能的影响。通过滴碱试验和铜加速乙酸盐雾(CASS)试验对改性前后阳极氧化膜的耐蚀性进行了研究,采用扫描电镜观察了不同阳极氧化膜的表面和截面形貌,测试了氧化膜的厚度,并对铈盐改性后的氧化膜进行了能谱分析,探讨了铈盐的作用机理。结果表明,稀土改性后得到的阳极氧化膜上孔分布均匀,孔隙率较高,其组成为Al2O3,氧化膜厚度由改性前的4.2μm提高到改性后的49.2μm,滴碱时间由35.9 s提高到186.9 s,CASS试验24、72和168 h的腐蚀评级分别由9、7和5级提高到10、9和8级。认为稀土盐的加入使氧化膜多孔层生长速率加快,阻挡层厚度增加,多孔部分结构更致密,从而提高了铝合金阳极氧化膜的耐蚀性能。
Abstracts： The influence of the modification of phosphoric-sulfuric acid anodizing by cerous sulfate, a rare earth salt, on corrosion resistance of 2A50 aluminum alloy was studied. The corrosion resistance of the anodic oxidation coatings obtained before and after modification was examined by alkali dropping test and CASS （copper- accelerated acetic acid salt spray） test. The surface and section morphologies of different anodic oxidation coatings were observed by scanning electron microscope. The thicknesses of the oxide coatings were measured. The oxide coating obtained after modification was analyzed by energy- dispersive spectroscopy. The action mechanism of the cerous salt was discussed. The results showed that the anodic oxidation coating obtained after modification features uniform pore distribution with high porosity, and is composed of Al2O3. The modification increases the thickness of anodic oxidation coating from 4.2 μm to 49.2μm, extending the time to failure in alkali dropping corrosion test from 35.9 s to 186.9 s, as well as improving the grade of CASS test result from 9 to 10 for 24 h, from 7 to 9 for 72 h, and 5 to 8 for 168 h. It is considered that the addition of rare earth salt can accelerate the growth of porous layer and increase the thickness of barrier layer for an oxidation coating, and make the structure of porous part more compact, resulting in the improved corrosion resistance of the anodic oxidation coating on aluminum alloy.
出处
《电镀与涂饰》
CAS
CSCD
北大核心
2014年第16期681-684,共4页
Electroplating & Finishing
关键词
铝合金
阳极氧化
硫酸铈
改性
耐蚀性
aluminum alloy
anodic oxidation
cerous sulfate
modification
corrosion resistance
