PVD法制备的TiAlN/Al2O3复合涂层氧化铝陶瓷刀具切削性能研究

摘要

An layer of hard, wear-resistant coating on the tool surface can effectively improve the cutting performance of the tool.At present, the research on tool coating mainly focuses on hard coatings such as nitrides, carbides and so on (the matrix is carbide).The oxide coating (the matrix is ceramic) has not yet made breakthrough progress.This paper deals with the preparation of nitride and oxide coatings on the surface of ceramic substrates and their cutting performance.Hard TiAlN antiwear coating (inner layer) and Al2O3anti-high temperature coating (outer layer) were prepared by the PVD-CAE and PEM-assisted PVD, respectively.The changes in microstructural and elemental composition of the coating were analyzed by SEM and EDS.The tool life of TiAlN/Al2O3coating, wear mechanism, and quality of the finished surface were studied by the continuous dry cutting of gray cast iron.The results show that this coating has a dense microstructure containing fine grains;the hard TiAlN coating improved the hardness of the cutting tools to 2781 ± 19HV50g.During the continuous dry cutting of gray cast iron, the main failure mode of uncoated tools is tipping damage, while the main failure mode of the TiAlN/Al2O3coated tools is abrasive wear and some adhesive wear;This coating tool life is 2 times more than that of conventional uncoated tool.and the finished surface has a good quality and stability.%在刀具表面沉积一层硬质、耐磨涂层,可有效提高刀具切削性能.目前刀具涂层的研究主要侧重于氮化物、碳化物等硬质涂层(基体为硬质合金),氧化物涂层(基体为陶瓷)仍未有突破性进展.文章涉及陶瓷基体表面的氮化物和氧化物涂层制备及切削性能研究.采用阴极电弧蒸发镀技术(PVD|CAE)和PEM辅助PVD工艺在氧化铝陶瓷刀具表面制备TiAlN硬质耐磨涂层(中间层)和Al2O3抗高温氧化涂层(外层).采用扫描电子显微镜(SEM)和EDS线扫法分析涂层微观结构和元素成分变化,通过显微硬度计表征涂层表面硬度.通过连续干切削灰铸铁试验研究TiAlN/Al2O3涂层的切削寿命、磨损机理和加工表面质量.结果表明:该复合涂层具有细晶致密的微观结构;TiAlN硬质层可将刀具表面硬度提升至2781±19HV50g,从而提高了刀具耐磨性;连续干切削灰铸铁试验中,无涂层氧化铝刀具发生崩刃破损,而TiAlN/Al2O3涂层刀具主要发生磨粒磨损和少量的粘结磨损,无崩刃现象;PVD法制备的TiAlN/Al2O3涂层刀具寿命是常规无涂层氧化铝刀具的2倍以上,且加工表面质量优良而稳定.