镁合金表面稀土转化膜的磷酸盐致密化及性能  

Phosphate Densification Technology and Properties of Rare Earth Conversion Films on Magnesium Alloy

作　　者：金亚旭[1] 董必坚 房大庆[1] 张博文 

机构地区：[1]太原科技大学,山西太原030024

出　　处：《稀有金属材料与工程》2017年第10期3077-3080,共4页Rare Metal Materials and Engineering

基　　金：太原科技大学校青年科技研究基金(20133008)

摘　　要：首先在AZ91镁合金表面上制备出镧铈双稀土转化膜,然后利用(NH_4)_3PO_4溶液进行致密化处理。采用扫描电镜(SEM)、X射线衍射仪(XRD)、高温氧化和电化学方法对致密化之后的转化膜形貌与性能进行研究。结果表明,对应用正交试验法确定的镧铈双稀土转化膜进行致密化处理的最佳工艺参数为:处理温度50℃、(NH_4)_3PO_4质量浓度5%、处理时间4 min。致密化后的膜层裂纹明显减少,表面致密性提高,很好地改善了对基体的覆盖度。经致密后的双稀土转化膜主要由稀土氧化物、氢氧化物、磷酸盐和氧化镁组成。致密化后的膜层耐蚀性显著提高。致密化后的双稀土转化膜的抗高温氧化性能优于未经致密化处理的双稀土转化膜。The densification process of lanthanum and cerium conversion film on AZ91 magnesium alloy was achieved by ammonium phosphate, and the orthogonal experiment was used to optimize the densification process. The properties of the film were investigated by scanning electronic microscopy（SEM）, X-ray diffractometer（XRD） and electrochemical methods. The results reveal that the treatment temperature is 50 °C,（NH_4）_3PO_4 mass concentration is 5%, and densification time is 4 min under the optimal treatment techniques. After the densification of the rare earth conversion film, cracks in the films decrease significantly, and the denseness of the conversion coatings is improved. The dual rare-earth conversion film with densification process is composed of rare earth oxides and hydroxides and phosphates and magnesium oxide. The corrosion resistance of the conversion film is strengthened. High temperature oxidation resistance of lanthanum and cerium conversion film with densification process is better than that of the film without densification process.

关 键 词：镁合金 稀土转化膜 致密化 耐蚀性 

分 类 号：TG174.4[金属学及工艺—金属表面处理]