急冷Al-Cr合金低温氧化制备自修复α-Al_2O_3薄膜

Preparation of self-healing α-Al_2O_3 film on rapid quenching Al-Cr alloy by thermal oxidation at low temperature

为了在750℃下制备自修复α-Al2O3薄膜,对Cr质量分数为8%和18%的急冷Al-Cr合金在大气气氛中670～720℃下进行氧化,并采用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)和能谱分析(EDS)对氧化膜进行分析.结果表明,Cr质量分数为8%的急冷Al-Cr合金主要由Cr固溶于Al的单相组织构成,质量分数为18%的急冷Al-Cr合金则为Al上分布Al45Cr7的双相组织.急冷Al-Cr合金可以在720℃的低温下通过氧化制备出薄且致密的α-Al2O3膜,合金的基体组织对氧化结果无明显影响,但Cr质量分数较高时,α-Al2O3膜中固溶有少量的Cr.此外,XRD检测结果表明,试样的表面粗糙度有利于获得α-Al2O3.

To prepare self-healing α-Al2O3 film below 750 ℃, the oxidation of rapid quenching Al-Cr alloy with Cr contents of 8 % and 18 % at 670-720 ℃ in air was studied. The oxide film was analyzed by XRD, SEM, TEM and EDS. The results show that the w（Cr）=8 % sample is one-phase solid solution of Cr in Al, while the w（Cr）=18 % sample is constituted of Al and Al45Cr7 phases. A compact α-Al2O3 film is prepared at 720 ℃ by the oxidation of Al-Cr alloy and, the rapid quenching alloy substrate has no obvious influence on the morphologies and phase constitutions of the oxide films. A few Cr is found in the α-Al2O3 film when the Cr content is larger. Moreover, XRD result shows that coarse surface facilitates the formation of the α-Al2O3.