摘要
采用真空蒸镀的方法在AZ91D镁合金表面沉积了锌铝复合涂层,之后在大气环境中,400℃,32 MPa压力下保温2 h。利用OM,SEM,EDS,XRD对涂层的表面形貌,断层结构,表层物相组成进行观察和分析,并对蒸镀锌铝涂层的镁合金进行显微硬度测试和耐蚀性试验。结果表明:在AZ91D表面获得了均匀的锌铝复合涂层,涂层与基体间形成了相互扩散的过渡层,结合二元相图及各点的EDS结果分析可知,在Mg/Zn界面形成的共晶相为Mg2Zn11或MgZn2,在A l/Zn界面形成的共晶相为A l2Zn3;热压处理的试样表面显微硬度达到了1360~1430MPa,为基体硬度的1.7~2.4倍;在3.5%的NaC l中性溶液中浸泡72 h后,热压试样的涂层未发现明显破裂,岛状组织仍然存在,试样表面只出现了少量黑色斑点状的腐蚀,未热压试样的涂层大片剥落,露出了亮白色的基体,涂层已起不到保护基体的作用,而AZ91D试样的基体组织受到了很大破坏,腐蚀坑呈大片的连续状,并有团絮状的腐蚀产物Mg(OH)2,这种疏松的结构不具有防护作用,可见热压涂层使镁合金表面的耐蚀性能得到了明显的改善。
Zinc-Aluminum composite coating on AZ91D alloy was successfully obtained by using vacuum evaporation technique and further kept warm for 2 h under the constant load of 32 MPa at 400 ℃ in the atmosphere.The surface morphology,the structure and the phase component of the coating were examined by OM,SEM,EDS and XRD.The microhardness and corrosion resistance of the AZ91D alloy coating were measured as well.The results showed that a homogeneous and dense Zn-Al composite coating was bonded tightly with the AZ91D ...
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2010年第5期678-683,共6页
Chinese Journal of Rare Metals
基金
山西省重点实验室开放基金(2008012013)
山西省科技攻关项目(20090321071)
太原市2009年科技明星专项项目(09121002)资助
关键词
AZ91D镁合金
真空蒸镀
耐蚀性
AZ91D magnesium alloy
vacuum evaporation
corrosion resistance
