Dense alumina-zirconia coatings using the solution precursor plasma spray process
Dense alumina-zirconia coatings using the solution precursor plasma spray process
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DOI：
10.1111/j.1551-2916.2007.02023.x
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发表时间：
2008-02-01
影响因子：
3.9
通讯作者：
Ma, Xinqing
中科院分区：
文献类型：
--
作者：
Chen, Dianying;Jordan, Eric H.;Ma, Xinqing
首次采用溶液前驱体等离子喷涂（SPPS）工艺制备了致密涂层。描述了致密的Al 2 O3 -40重量%的7 YSZ（氧化钇稳定的氧化锆）涂层的沉积条件，涂层的特征在于，并评价其热稳定性。X射线衍射分析表明，涂层由α-Al 2 O3和四方ZrO 2相组成，晶粒尺寸分别为72和56 nm。喷涂后的涂层密度为95.6%，由1-5 μ m的超细片状物和< 0.5 μ m的未熔化的球形颗粒组成。典型的常规等离子喷涂涂层的层状结构在SPPS涂层中不存在相同的尺度。致密的Al 2 O 3 -40重量%的7 YSZ涂层的形成是有利的低共熔组合物的较低熔点，和由此产生的过热的熔融颗粒。通过在1000 ℃-1500 ℃的温度下对喷涂涂层进行热处理，研究了相和微观结构的热稳定性。在1500 ℃暴露2 h后，没有发生相变，并且晶粒尺寸仍然在纳米范围内。由于涂层孔隙率的降低，涂层硬度从涂覆状态下的11.8 GPa增加到1500 ℃暴露后的15.8 GPa。
For the first time, dense coatings have been made by the solution precursor plasma spray (SPPS) process. The conditions are described for the deposition of dense Al2O3-40 wt% 7YSZ (yttria-stabilized zirconia) coatings; the coatings are characterized and their thermal stability is evaluated. X-ray diffraction analysis shows that the as-sprayed coating is composed of alpha-Al2O3 and tetragonal ZrO2 phases with grain sizes of 72 and 56 nm, respectively. The as-sprayed coating has a 95.6% density and consists of ultrafine splats (1-5 mu m) and unmelted spherical particles (< 0.5 mu m). The lamellar structure, typical of conventional plasma-sprayed coatings, is absent at the same scale in the SPPS coating. The formation of a dense Al2O3-40 wt% 7YSZ coating is favored by the lower melting point of the eutectic composition, and resultant superheating of the molten particles. Phase and microstructural thermal stabilities were investigated by heat treatment of the as-sprayed coating at temperatures of 1000 degrees-1500 degrees C. No phase transformation occurs, and the grain size is still in the nanometer range after the 1500 degrees C exposure for 2 h. The coating hardness increases from 11.8 GPa in the as-coated condition to 15.8 GPa following 1500 degrees C exposure due to a decrease in coating porosity.