磁控溅射-热处理两步法制备Cr2AlC涂层及力学性能

Mechanical Properties of Cr_2AlC Coatings Prepared by DC Magnetron Sputtering and Heat Treatment

Cr_2AlC属于三元层状化合物MAX相,其兼具金属和陶瓷的综合性能,如金属的导热、导电、可加工性,陶瓷的抗氧化、耐腐蚀等性能。利用直流磁控溅射技术和后续退火工艺在高速钢基体上制备了Cr_2AlC涂层,采用XRD、SEM等研究了气体流量及热处理工艺对涂层成分和物相组成的影响。结果表明：气体流量和退火温度对Cr_2AlC相的形成至关重要,气体流量比过大和退火温度过高均不利于Cr_2AlC的形成。不同气体流量下沉积态涂层主要由Cr-C化合物、非晶或者纳米晶等组成,均没有发现Cr_2AlC相;涂层经750℃退火后不同气体流量比涂层均有一定量Cr_2AlC相形成;且Cr_2AlC相形成的温度范围随CH_4/Ar气体流量比增加而变窄。含Cr_2AlC MAX相涂层的硬度为10.6-17.6GPa,弹性模量为255.3-323.4GPa。

Ternary layered carbide Cr_2 AlC is a typical MAX phase.This compound possesses a unique combination of the merits of both metals and ceramics,such as good thermal conductivity,conductive,easy machinability,good corrosion and excellent oxidation resistance.Cr_2 AlC coatings were prepared on high speed steel substrate by DC magnetron sputtering method combined with heat post-treatment in this study.The influence of gas flow rates and heat treatmenttemperature on the composition and phase in the coatings were also characterized with XRD and SEM.The results show that：the gas flow rate and heat treatment temperature play key roles on the formation of Cr_2 AlC MAX phase.The formation of Cr_2 AlC phase is suppressed by the increment of CH_4/Ar gas flow rates and the enhancement of annealing temperature.The as-deposited coatings mainly consist of Cr-C compound and amorphous,however,Cr_2 AlC phases can be acquired after being annealed at 750 ℃ for coatings with different gas flow rate.The temperature range of Cr_2 AlC phase formation can decrease with increasing CH_4/Ar flow rate ratio.The nano-hardness and elastic modulus of coatings contain Cr_2 AlC MAX phase are 10.6-17.6GPa and 255.3-323.4GPa.