CAJ | 학술논문

在K2ZrF6-Na2SiO3电解液中对Y(NO3)3浸泡预处理的AZ91D镁合金进行微弧氧化处理,在镁合金表面制备Y2O3-ZrO2-MgO复合膜层(YSZ-MgO膜).运用电子显微镜(SEM)、能谱分析(EDX)、X射线衍射(XRD)和电化学分析与高温氧化等方法研究YSZ-MgO膜的组成与结构、耐腐蚀性及热稳定性.结果表明,YSZ-MgO膜主要由Y2O3、ZrO2、MgO和Mg2SiO4等物相组成,和未经Y(NO3)3浸泡的膜层(ZrO2-MgO膜)相比,YSZ-MgO膜的厚度较小,但膜层的致密性较好,表面粗糙度较小；且腐蚀电流密度较小、开路电位较正、极化阻抗较高;在5％NaCl溶液中的腐蚀速率低于ZrO2-MgO膜的,约为AZ91D镁合金的8％.YSZ-MgO膜层比普通ZrO2-MgO膜层具有更强的抗高温氧化性能和耐热冲击性能.
재K2ZrF6-Na2SiO3전해액중대Y(NO3)3침포예처리적AZ91D미합금진행미호양화처리,재미합금표면제비Y2O3-ZrO2-MgO복합막층(YSZ-MgO막).운용전자현미경(SEM)、능보분석(EDX)、X사선연사(XRD)화전화학분석여고온양화등방법연구YSZ-MgO막적조성여결구、내부식성급열은정성.결과표명,YSZ-MgO막주요유Y2O3、ZrO2、MgO화Mg2SiO4등물상조성,화미경Y(NO3)3침포적막층(ZrO2-MgO막)상비,YSZ-MgO막적후도교소,단막층적치밀성교호,표면조조도교소；차부식전류밀도교소、개로전위교정、겁화조항교고;재5％NaCl용액중적부식속솔저우ZrO2-MgO막적,약위AZ91D미합금적8％.YSZ-MgO막층비보통ZrO2-MgO막층구유경강적항고온양화성능화내열충격성능.
A composite ceramic coating containing Y2O3-ZrO2-MgO (YSZ-MgO) was prepared on AZ91D magnesium alloy,which was immersed in Y(NO3)3 aqueous solution as pretreatment,by micro-arc oxidation (MAO) process.The morphology,elemental and phase compositions,corrosion behavior and thermal stability of the coatings were studied by SEM,EDX,XRD,electrochemical corrosion test,high temperature oxidation and thermal shock test.The results show that the coating mainly consists of ZrO2,Y2O3,MgO,Mg2SiO4,and MgF2.Among these compounds,Y2O3 accounts for 26.7％ of (Y2O3 + ZrO2).The thickness of YSZ-MgO coating is smaller than that of ZrO2-MgO coating,but its compactness and surface roughness are better than those of ZrO2-MgO coating.YSZ-MgO coating has a good corrosion resistance,and its corrosion rate in 5％ NaCl aqueous solution is lower than that of ZrO2-MgO and only about 8.5％ of that of AZ91D magnesium alloy.After oxidation at 410 ℃,the mass gain of AZ91D magnesium alloy presents a linear increase with the oxidation time.The YSZ-MgO coating and ZrO2-MgO coating can remarkably decrease the oxidation mass gain.The oxidation mass gain of YSZ-MgO coating is lower than that of ZrO2-MgO coating,especially during a long oxidation period.The thermal shock resistance of YSZ-MgO coating is superior to ZrO2-MgO coating.