Effects of thermal annealing on the microstructure of sputtered Al2O3 coatings
Effects of thermal annealing on the microstructure of sputtered Al2O3 coatings
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DOI：
10.1116/1.3584803
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发表时间：
2011-06
期刊：
影响因子：
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通讯作者：
V. Edlmayr;T. Harzer;R. Hoffmann;D. Kiener;C. Scheu;C. Mitterer
中科院分区：
文献类型：
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作者：
V. Edlmayr;T. Harzer;R. Hoffmann;D. Kiener;C. Scheu;C. Mitterer
采用透射电镜研究了脉冲直流磁控溅射制备的Al2O3薄膜在生长状态下和在1000℃真空退火12 h后的形貌和微观结构。对于在低离子轰击条件下沉积的涂层，薄膜由嵌入在非晶基体中的小γ-和/或δ-Al2O3晶粒组成。靠近基体界面区域的晶粒尺寸比剩余层的晶粒尺寸大得多。退火过程促进了γ-Al2O3相的生长，但没有发现α-Al2O3相的转变。在高能生长条件下，涂层上部有明显的γ-Al2O3形成，晶粒尺寸明显大于低能生长条件下的γ-Al2O3，但薄膜在界面区以非晶态为主。退火使γ-Al2O3转变为α-Al2O3，非晶部分主要结晶为γ-Al2O3。
The morphology and microstructure of Al2O3 thin films deposited by pulsed direct current magnetron sputtering were studied in the as-grown state and after vacuum annealing at 1000 °C for 12 h using transmission electron microscopy. For the coating deposited under low ion bombardment conditions, the film consists of small γ- and/or δ-Al2O3 grains embedded in an amorphous matrix. The grain size at the region close to the interface to the substrate was much larger than that of the remaining layer. Growth of the γ-Al2O3 phase is promoted during annealing but no transformation to α-Al2O3 was detected. For high-energetic growth conditions, clear evidence for γ-Al2O3 formation was found in the upper part of the coating with grain size much larger than for low-energetic growth, but the film was predominately amorphous at the interface region. Annealing resulted in the transformation of γ-Al2O3 to α-Al2O3, while the mainly amorphous part crystallized to γ-Al2O3.