田宗軍1，張建華1， 張永康3
(1. 南京航空航天大學 機電學院， 南京 210016;
2. 南通工學院 機械工程系, 南通 226007;
3. 江蘇大學 機械工程學院， 鎮(zhèn)江 210013)
摘 要: 采用X射線衍射儀、 掃描電鏡和顯微硬度計研究了45#鋼表面激光熔覆納米Al2O3改性Al2O3+13%TiO2（質(zhì)量分數(shù)）陶瓷涂層的相組成、微觀結(jié)構(gòu)和顯微硬度， 同時對涂層的磨損特性進行了考察。 結(jié)果表明， 激光重熔區(qū)亞穩(wěn)相γ-Al2O3轉(zhuǎn)變成穩(wěn)定相α-Al2O3， 熔覆層由粗顆粒α-Al2O3和TiO2以及納米α-Al2O顆粒組成， 在激光的作用下， 等離子噴涂層的片層狀結(jié)構(gòu)得以消除；納米Al2O3顆粒仍然保持在納米尺度，填充在涂層的大顆粒之間， 使涂層致密化程度得以提高， 因此納米Al2O3改性涂層的顯微硬度較高，且其耐磨性能明顯優(yōu)于等離子噴涂層。
關(guān)鍵字: 納米Al2O3顆粒； Al2O3； TiO2； 等離子噴涂；復合陶瓷涂層； 激光熔覆
Al2O3 nano-particles
TIAN Zong-jun1, ZHANG Jian-hua1, ZHANG Yong-kang3
（ 1. College of Mechanical and Electrical Engineering,
Nanjing University of Aeronautics and Astronautics,
Nanjing 210016, China;
2. Department of Mechanical Engineering,
Nantong Institute of Technology, Nantong 226007, China;
3. College of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, China）
Abstract: The phase constitution, microstructure and microhardness of Al2O3+13%TiO2(mass fraction) composite ceramic coatings laser-claded by Al2O3 nano-particles on 45# steel were investigated using X-ray diffractometry, scanning electron microscopy and microhardness measurement. Also, wear behavior of the coatings was studied. The results show that the metastable γ-Al2O3 phases in the cladding area transfer into stable phase of α-Al2O3, composite ceramic coating consists of α-Al2O3 and TiO2, and lamellar structure of plasma-sprayed coatings is eliminated after the laser-cladding. A large number of Al2O3 nano-particles are found among the large particles of the ceramic coating and play an important role in improving the density of the ceramic coating. So laser-claded nano-Al2O3 ceramic coating has higher hardness and better wear resistance than plasma sprayed Al2O3+13%TiO2 coating does.
Key words: Al2O3 nano-particle; alumina; titania; plasma spraying; composite ceramic coating; laser cladding
