基于ALD低温制备的纳米涂层刀具性能研究

Research on Performance of Nano-coated Tools Prepared by ALD at Low Temperature

目的探索基于原子层沉积法(Atomic Layer Deposition, ALD)的纳米涂层低温制备技术,并重点研究涂层沉积过程及纳米氧化铝涂层对刀具力学性能的影响。方法利用原子层沉积法,在200℃的环境下制备不同涂层厚度的纳米Al_2O_3涂层刀具,对涂层的微观组织、厚度、硬度、断裂韧性、断口形貌、弯曲强度、结合力及摩擦系数进行检测。结果 ALD沉积技术能将纳米涂层均匀沉积在YT5刀具表面,且涂层光滑,无滴状气泡,涂层厚度可以精确控制在纳米级。ALD涂层与基体结合力的大小与涂层厚度相关,随着涂层厚度增大,结合力呈先增后降的趋势,测得50、100、200 nm等3种纳米涂层结合力大小分别为11.07、12.74、7.86N。纳米涂层能够提高刀具的硬度,显著降低刀具表面的摩擦系数,测得刀具摩擦系数分别为0.56、0.43、0.67,最高降低摩擦系数达40%以上。此外在200℃的沉积温度下,没有产生金属相变,因而对刀具基体没有影响,刀具的断裂韧性和弯曲强度没有降低。结论基于ALD的纳米涂层低温沉积技术所制备的纳米涂层刀具,具有良好的力学性能及涂层-基体界面结合力,能显著提高刀具性能,改善切削加工条件。

The work aims to explore the low-temperature preparation technology of nano-coating based on Atomic Layer Deposition(ALD),and focus on the coating deposition process and the influence of nano-alumina coating on the mechanical properties of nano-alumina coated tools.Nano-Al2O3 coatings with different thicknesses were prepared by Atomic Layer Deposition at 200℃.The microstructure,thickness precision,hardness,fracture toughness,bending strength,bonding force,and friction coefficient of the coating were tested.The ALD deposition technology can uniformly deposit nano-coating on the surface of the YT5 cutter,and the coating is smooth and free of dripping bubbles,and the thickness of the coating can be accurately controlled at nano-thickness.The binding force between ALD coating and substrate is related to the coating thickness.With the increase of coating thickness,the binding force increases first and then decreases.The binding force of 50,100,and 200 nm nano-coatings is measured to be 11.07,12.74,and 7.86 N respectively.Nano-coating can improve the hardness of the tool and significantly reduce the friction coefficient of the tool surface.The measured friction coefficients of the tool are 0.56,0.43,and 0.67 respectively,and the maximum reduction of the friction coefficient is over 40%.In addition,the deposition temperature of 200℃does not produce metal phase transformation,thus it has no influence on the tool matrix,and the fracture toughness and bending strength of the tool does not reduce.The nano-coating tool prepared by ALD-based nano-coating low-temperature deposition technology has good mechanical properties and coating-substrate interface bonding force,which can significantly improve micro-cutting processing conditions and have broad application prospects in the micro-cutting field.