Preparation and characterization of nanostructured Al2O3-13wt.%TiO2 ceramic coatings by plasma spraying
来源期刊：Rare Metals2009年第5期
论文作者：WANG Dongshenga, b, TIAN Zongjuna, b, SHEN Lidab, LIU Zhidonga, b, and HUANG Yinhuia, b a Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology, Nanjing University of Aeronautics and Astronautics, Nanjing , China b College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing , China
文章页码：465 - 470
摘 要：Nanostructured and conventional Al2O3-13wt.%TiO2 ceramic coatings were prepared by plasma spraying with nanostructured agglomerated and conventional powders, respectively. The microstructure and microhardness of the coatings were investigated using scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, and microhardness measurement. Meanwhile, the friction and wear behaviors were analyzed and compared using a ball-on-disk tribometer. The results show that the conventional coating has lamellar stacking characteristic and has some pores. However, the nanostructured coating shows a bimodal microstructure, which is composed of both fully melted regions and partially melted regions. According to the microstructural difference, the partially melted regions can be divided into liquid-phase sintered regions （a three-dimensional net or skeleton-like structure: Al2O3-rich submicron particles embedded in the TiO2-rich matrix） and solid-phase sintered regions （remained nanoparticles）. The microstructural characteristics of the liquid-phase sintered region are formed due to the selective melting of TiO2 nanoparticles during plasma spraying. On the other hand, the TiO2 and Al2O3 nanoparticles of the solid-phase sintered regions are all unmelted during plasma spraying. Due to the existence of nanostructured microstructures, the nanostructured coating has a higher microhardness, a lower friction coefficient, and a better wear resistance than the conventional coating.
WANG Dongshenga, b, TIAN Zongjuna, b, SHEN Lidab, LIU Zhidonga, b, and HUANG Yinhuia, b a Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China b College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
摘 要：Nanostructured and conventional Al2O3-13wt.%TiO2 ceramic coatings were prepared by plasma spraying with nanostructured agglomerated and conventional powders, respectively. The microstructure and microhardness of the coatings were investigated using scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, and microhardness measurement. Meanwhile, the friction and wear behaviors were analyzed and compared using a ball-on-disk tribometer. The results show that the conventional coating has lamellar stacking characteristic and has some pores. However, the nanostructured coating shows a bimodal microstructure, which is composed of both fully melted regions and partially melted regions. According to the microstructural difference, the partially melted regions can be divided into liquid-phase sintered regions （a three-dimensional net or skeleton-like structure: Al2O3-rich submicron particles embedded in the TiO2-rich matrix） and solid-phase sintered regions （remained nanoparticles）. The microstructural characteristics of the liquid-phase sintered region are formed due to the selective melting of TiO2 nanoparticles during plasma spraying. On the other hand, the TiO2 and Al2O3 nanoparticles of the solid-phase sintered regions are all unmelted during plasma spraying. Due to the existence of nanostructured microstructures, the nanostructured coating has a higher microhardness, a lower friction coefficient, and a better wear resistance than the conventional coating.
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