摘要
利用磷酸盐溶液在AZ31镁合金挤压型材表面获得转化膜。用扫描电镜(SEM),X射线衍射(XRD)和质量损失检测等试验手段,对膜层生长和形貌特征进行了研究,对其表面膜层的成膜机理进行了探讨。结果表明,膜层生长初期基材腐蚀溶解迅速,质量损失超过整个损失的2/3;磷酸盐呈双膜层结构,底层为鳞片条带状相间分布,具有方向性。由于底层由微结构差异较大膜组成,这种微结构的差异使得两类膜之间结合处出现明显的狭缝,成为影响底层膜耐蚀性的根本原因之一;基材的微观组织特点和化学状态直接影响底层膜层的生长特征。
Chemical conversion coating was prepared on AZ31 magnesium alloy profile in phosphate solution.Growth and morphology characteristics of coating were analyzed by SEM(scanning electron microscope),XRD(X-ray diffraction)and mass-loss measuring method,and the formation mechanism of the conversion coating was approached.Mass-loss testing shows that there exists rapid corrosion dissolution of the alloy matrix accounting for more than 2/3 of the whole mass-loss in the early growth stage of the coating.Phosphate conversion coating exhibits two-layer structure,in which substrate layer consisting of interphase banding distribution of scaly and stripy structure exhibits orientation.The obvious slot between the bonding location of the two layer can be observed as a result of microstructure difference,which is responsible for the decrease of corrosion resistance of the substrate layer.Growth characteristics of phosphate conversion coatings were closely relevant to the microstructure features and chemical state of the matrix alloy.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2009年第6期573-575,共3页
Special Casting & Nonferrous Alloys
基金
江西省教育厅科技项目(赣教技字[2006]1号)
江西省教育厅项目(GJJ08007)
南昌大学校基金资助项目(Z03349)
关键词
镁合金
磷酸盐
转化膜
生长特征
Magnesium Alloy,Phosphate,Conversion Coating,Growth Characteristics
