(1. 南昌航空大学 轻合金加工科学与技术国防重点学科实验室，南昌 330063；
2. 中国航发贵州黎阳航空动力有限公司，黎阳 550014；
3. 北京科技大学 腐蚀与防护中心，北京 110083)
摘 要: 在硅酸盐和磷酸盐混合电解液体系中加入不同粒径HBN颗粒，通过等离子体氧化法(PEO)在7075-T6合金表面制备Al2O3/HBN复合膜；利用SEM、EDS、XRD、磨损实验、电化学极化曲线等对复合膜的组织结构、化学组成、耐磨及耐蚀性能进行表征。结果表明：HBN颗粒加速了膜层的击穿放电过程，对PEO膜的前期生长有促进作用，且所得膜层较为致密，但膜层粗糙度有所增加。电解液中加入4g/L的HBN颗粒，无论HBN粒径为5、10或30 μm，均能使PEO膜的表层微孔数量及内部缺陷有所减少，且复合膜中晶态Al2O3相含量也有所增长。相比于PEO膜，HBN颗粒复合的PEO/HBN复合膜的摩擦因数更小、比磨损率更低、摩擦磨损性能均有所改善；且HBN粒径为10 μm时，复合膜的耐磨性更佳，比磨损率降低近42.5%。此外，PEO/HBN复合膜的耐蚀性更优，其自腐蚀电流密度较未复合的PEO膜下降了1个数量级；5 μm粒径HBN复合的膜层经模拟海水浸泡1800 h后表面腐蚀较轻微。
关键字: 7075-T6合金；PEO；HBN颗粒；微观结构；性能
（1. National Defense Key Discipline Laboratory of Light Alloy Processing Science and Technology, Nanchang Hangkong University, Nanchang 330063, China;
2. AECC Guizhou Liyang Aviation Power Co., Ltd., Liyang 550014, China;
3. Corrosion and Protection Center, University of Science and Technology Beijing, Beijing 100083, China）
Abstract:Al2O3 /HBN composite coatings were prepared on 7075-T6 aluminum alloy by plasma electrolysis oxidation (PEO) in silicate-phosphate mixed electrolyte with HBN particles of different sizes. The microstructure, composition, wear resistance and corrosion resistance of the composite coating were analyzed by SEM, EDS, XRD, wear test and polarization curves. The results show that HBN particles can accelerate the breakdown discharge process of coating, and promote the pre-growth stage of PEO coating. The incorporation of HBN particles also makes PEO coating more dense, but increase the roughness. Whether HBN particle size is 5, 10 or 30 μm, the addition of 4 g/L HBN particles in the electrolyte can reduce the surface micropores number and the internal defects of PEO coating, and make the coating surface be flatter. The content of Al2O3 crystal phase in the PEO composite coatings also increases. Compared with PEO coating, the PEO/HBN composite coatings have smaller friction coefficient, lower wear rate and better wear properties. Among them, the PEO composite coating prepared in electrolyte containing 10 μm HBN particles shows the best wear resistance, and the specific wear rate decreases by 42.5%. Besides, the PEO/HBN composite coatings have better corrosion resistance, the corrosion current density is one order of magnitude lower than that of the uncomposited PEO coating, and the surface corrosion of PEO sample prepared in electrolyte with 5 μm HBN particles is the slightest after 1800 h simulated seawater immersion test.
Key words: 7075-T6 alloy; PEO; HBN particles; micro-structure; performances
