摘要
为改善7A85新型铝合金表面的耐蚀和耐磨性能,利用微弧氧化技术在其表面原位生成陶瓷膜层,用稀土铈盐溶液对陶瓷膜进行封孔处理。通过扫描电子显微镜观察陶瓷膜的表面形貌,采用X射线衍射仪分析膜层的相结构,利用盐雾腐蚀试验和电化学测试评价了陶瓷膜的耐蚀性能,用球-盘摩擦磨损试验机研究了陶瓷膜的摩擦学性能。结果表明:7A85铝合金表面微弧氧化陶瓷膜主要由α-Al2O3和γ-Al2O3相组成,陶瓷膜表面经稀土封孔处理后致密性提高。单纯的微弧氧化处理提高了7A85铝合金的耐腐蚀性能,使其抗3.5%NaCl水溶液腐蚀速率降低了1个数量级;对微弧氧化膜层进行稀土铈盐封孔处理进一步提高了膜层的耐蚀性能,腐蚀速率降低1个数量级。微弧氧化陶瓷膜显著提高了7A85铝合金表面的耐磨性能,体积磨损率从4.56×10-3mm3/(N·m)降至5.73×10-4mm3/(N·m);稀土铈盐封孔处理降低了陶瓷膜的摩擦系数,但对磨损速率无显著影响。
In order to improve the corrosion and wear resistance of new 7A85 aluminum alloy,in-situ ceramic coatings on the new 7A85 aluminum alloy were fabricated by micro-arc oxidation( MAO),and sealed with rare earth cerium solution. The surface morphology and phase composition of ceramic coatings were investigated by SEM and XRD. Salt spray tests and electrochemical measurement techniques were used to investigate the corrosion behavior of ceramic coatings. The tribological properties of ceramic coatings were carried out under dry sliding using ball-ondisc test rig. The results indicate that the ceramic coating on the new 7A85 aluminum alloy is mainly composed of α-Al 2 O 3 and γ-Al 2 O 3 phase,the ceramic coatings were uniform and compact after cerium salt sealing treatment. The micro-arc oxidation treatment can effectively improve the corrosion resistance of new 7A85 aluminum alloy in 3.5%NaCl solution,making the corrosion rate decrease by 1 order of magnitude. The sealing treatment by rare earth cerium salt on the MAO coatings can further improve the corrosion resistance of the ceramic coatings with corrosion rate reducing by another 1 order of magnitude. The MAO treatment can improve the wear resistance of new 7A85 alloy remarkably,with the volumetric wear rate decrease from 4.56×10-3mm3/( N·m) to 5.73×10-4mm3/( N·m). The sealing treatment by rare earth cerium salt on the ceramic coatings decreases the friction coefficient,but has no significant influence on the wear rate.
出处
《机械科学与技术》
CSCD
北大核心
2014年第1期127-132,共6页
Mechanical Science and Technology for Aerospace Engineering
基金
国家自然科学基金项目(51171154)资助
关键词
微弧氧化技术
封孔处理
耐蚀性能
耐磨性能
铝合金
稀土铈
铈盐
陶瓷膜层
aluminum alloys
ceramic coatings
cerium compounds
corrosion rate
corrosion resistance
corrosion
electro chemistry
experiments
friction
measurements
oxidation
phase composition
rare earth compounds
scanning electron microscopy
sealing(closing)
surface morphology
tribology
wear resistance
X ray diffraction
7A85 aluminum alloy
micro-arc oxidation
vare earth salt sealing
