Si含量对VAlSiN涂层微结构、力学性能和摩擦磨损性能的影响

采用反应磁控溅射技术,在300℃下制备不同Si含量的VAlSiN涂层。研究Si含量的变化对VAlSiN涂层相结构、生长形貌、化学状态、力学性能和摩擦磨损性能的影响。结果表明:不含Si的VAlN涂层呈现(111)择优取向生长。随着Si含量的增加,VAlSiN涂层的(111)择优取向逐渐消失,最终转变为非晶结构。Si含量大于1.8%(原子分数,下同)的VAlSiN涂层是由nc-VAlN和a-Si_3N_4组成的多相复合涂层。与VAlN涂层相比,添加少量Si(0.8%)的VAlSiN涂层晶粒尺寸减小,致密度得到提高,对应的涂层硬度也得到显著增大,达到30.1GPa。继续增加Si的含量,VAlSiN涂层的柱状生长结构被打断,硬度逐渐下降,最后稳定在22GPa左右。VAlSiN涂层的摩擦因数随着Si含量的增加先降低后升高。当Si含量为0.8%时涂层的磨损率最低,达1.2×10~(-16)m~3·N~(-1)·m~(-1)。

Influence of Si Content on Microstructure,Mechanical Properties and Tribological Properties of VAlSiN Coatings

VAlSiN coatings with different Si contents were deposited at 300℃ by reactive magnetron sputtering.The effect of Si content on the microstructure, growth morphology,chemical state, mechanical properties,friction and wear properties was investigated.The results show that the VAlN coating exhibits a single-phase NaCl structure with (111) preferred orientation.The VAlSiN coatings gradually lose their structure of (111) preferred orientation and transfer into amorphous structure with the increase of Si content.The VAlSiN coatings which Si content is more than 1.8% (atom fraction,same as below) are multi-phase composite coatings consisting of nc-VAlN and a-Si3N4.Compared to VAlN coating, the density of VAlSiN coatings with small amount of Si (0.8%) is increased significantly as well as the hardness that reaches 30.1GPa,while the grain size is decreased.Further increasing Si content, the growth of columnar grains is interrupted, concomitant of the hardness gradually declines and tends to be stable at 22GPa.The friction coefficient of the VAlSiN coatings decreases first and then increases with the increase of Si content.The wear rate reaches the lowest value of 1.2×10-16 m3·N-1·m-1 is obtained when Si content is 0.8%.