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用Al(NO3)3.9H2O、ZrOCl2.8H2O及NH4OH作为原料,采用溶胶–凝胶工艺制备出Al2O3–40%(质量分数)ZrO2纳米复合粉体。并以此粉体为原料,用等离子喷涂工艺在不锈钢基体上制备了Al2O3–40%ZrO2纳米涂层。采用X射线衍射、扫描电子显微镜及高分辨透射电子显微镜分析粉体及涂层的物相及微观结构。结果表明:当煅烧温度从900℃升高至1 200℃过程中,复合粉体中的θ-Al2O3逐渐向α-Al2O3转变,当煅烧温度达到1 200℃时,粉体中仅存在α-Al2O3。此外,单斜相二氧化锆(m-ZrO2)与四方相二氧化锆(t-ZrO2)共存于粉体中,并且m-ZrO2含量随煅烧温度及保温时间的增加而增加。喷涂后的Al2O3–40%ZrO2纳米涂层是由尺寸约为50 nm的晶粒及一些非晶相组成,晶粒的物相为α-Al2O3、γ-Al2O3及t-ZrO2。
Al (NO3) 3.9H2O, ZrOCl2.8H2O and NH4OH were used as raw materials to prepare Al2O3-40% (mass fraction) ZrO2 nano-composite powders by sol-gel process. The Al2O3-40% ZrO2 nano-coating was prepared on the stainless steel substrate by plasma spray process. The phase and microstructure of the powders and coatings were analyzed by X-ray diffraction, scanning electron microscopy and high resolution transmission electron microscopy. The results show that the θ-Al2O3 phase in the composite powders gradually changes to α-Al2O3 when the calcination temperature is raised from 900 ℃ to 1200 ℃. When the calcination temperature reaches 1 200 ℃, only α-Al2O3 . In addition, m-ZrO2 and tetragonal zirconium dioxide (t-ZrO2) co-existed in the powder, and the content of m-ZrO2 increased with calcination temperature and holding time. The sprayed Al2O3-40% ZrO2 nano-coating consists of crystal grains with a size of about 50 nm and some amorphous phases. The phases of the grains are α-Al2O3, γ-Al2O3 and t-ZrO2.