【摘要】 目的研究等离子喷涂Al-Nb₂O₅铝热体系制备的AlNbO₄-Al₂O₃-NbO_x复合涂层的组织、力学性能和摩擦磨损性能。方法以Nb₂O₅粉和Al粉为原料,通过喷雾造粒制备复合粉,采用等离子喷涂技术喷涂Al-Nb₂O₅复合粉体,利用复合粉的自反应制备出含有AlNbO₄、Al₂O₃和NbO_x的复合陶瓷涂层。利用扫描电镜、EDS和XRD检测和分析复合涂层的组织和物相。用显微硬度计测定复合涂层的硬度,并用硬度压痕法测量裂纹扩展能（Gc）。用销盘式磨损试验机测定涂层在无润滑条件下的摩擦磨损性能。结果 XRD分析可知,复合涂层由AlNbO₄、Al₂O₃和NbO_x相组成,SEM显示涂层为交替分布的层片状组织。在28³2 k W功率范围内,随着喷涂功率的升高,涂层的硬度增加,喷涂功率为32 k W时,涂层硬度最高,为912HV0.1。随着喷涂功率的升高,涂层的裂纹扩展能先升高后降低,喷涂功率为30 k W时,涂层的裂纹扩展能最大,为14.14J/m2。摩擦系数随功率的升高先降低后保持不变,28 k W时,涂层的摩擦系数为0.7⁰.8,30 k W和32 k W时,涂层的摩擦系数为0.5⁰.6。磨损量随喷涂功率的增加先降低后升高,喷涂功率为30 k W时,涂层的磨损量最小。磨损后的试样进行SEM检测发现有明显的犁沟、凹槽和剥落。结论涂层具有由AlNbO₄、Al₂O₃和NbO_x相组成的交替分布的多相层片状组织。喷涂功率为30 k W时,复合涂层的性能最好。复合涂层的主要磨损机制为磨粒磨损和疲劳磨损。更多还原

【Abstract】 The work aims to study microstructure, mechanical properties as well as friction and wear properties of AlNbO₄-Al₂O₃-NbO_x composite coating prepared by plasma spraying in Al-Nb₂O₅ thermit system. A composite ceramic coating containing AlNbO₄, Al₂O₃ and NbO_x was fabricated by plasma spraying self-made Al-Nb₂O₅ composite powder prepared by spray granulation with Nb₂O₅ and Al powders. Structure and phase composition of the composite coating were tested and analyzed with a scanning electron microscope（SEM）, energy dispersive analyzing system（EDS） and X-ray diffractometer（XRD）, microhardness with a microhardness tester and crack extension force（Gc） in hardness indentation method. The friction and wear properties of the unlubricated coatings were tested with pin-disc-type abrasion tester. The XRD analysis showed that the composite coating consisted of AlNbO₄, Al₂O₃ and NbO_x phases. The SEM results showed that the coating had an alternatively distributed lamellar structure. In the range of 28³2 kW, hardness of the coating increased with the increase of spraying power and was up to 912HV0.1 at 32 kW; crack extension force of the coating increased firstly then decreased and the maximum was 14.14 J/m2 at 30 kW; the friction coefficient decreased firstly and then remained constant with the increase of power; the friction coefficient was 0.7⁰.8 at 28 kW, and 0.5⁰.6 at 30 kW and 32 kW; the wear volume decreased firstly and then increased, and amounted to the minimum at 30 kW. Obvious furrow, groove and peeling-off were observed on the worn sample. The composite coatings have an alternatively distributed multiphase lamellar structure consisting of AlNbO₄, Al₂O₃ and NbO_x. Performance of the composite coating is the best at the spraying power of 30 kW. Main wear mechanisms of the composite coating are abrasive wear and fatigue wear.更多还原