钛合金表面非平衡磁控溅射制备氮化钛薄膜性能研究

Improvement of Mechanical Heart Valve with TiN Films Grown on Ti Alloys

本文利用非平衡磁控溅射技术,通过改变薄膜沉积时氮气和氩气分压比(PN/PAr)和靶基距,在Si(100)和钛合金(Ti6A14V)基体上制备了氮化钛薄膜。利用X射线衍射(XRD)、扫描电子显微镜(SEM)、HXD^1000显微硬度仪和(CSEM)销盘摩擦磨损实验机对氮化钛薄膜的晶体结构、断面形貌、显微硬度和耐磨性进行了表征。研究发现,利用非平衡磁控溅射制备出致密的氮化钛薄膜,PN/PAr较小时,氮化钛薄膜中存在Ti2N相,Ti2N能够提高薄膜的硬度与耐磨性,随着N2/Ar的提高,薄膜硬度、耐磨性提高,当PN/PAr达到0.1时,随着N2/Ar的提高,薄膜硬度、耐磨性降低。结果表明,在钛合金表面制备氮化钛薄膜可以显著提高钛合金表面硬度与耐磨性,在改善用于人工心脏瓣膜的力学性能,提高人工心脏瓣膜的瓣架耐磨性,提高人工心脏瓣膜的寿命方面有较广阔的应用前景。

Titanium nitride films were grown by unbalanced magnetron sputtering on substrates of Si（100） and Ti alloy at different partial pressure ratios of N2 and Ar and at different target substrate separations. The films were characterized with X-ray diffraction （XRD）, scanning electron microscopy （SEM） and some conventional mechanical probes. The results show that the ratio significantly affects the mechanical properties, such as its compatness, its hardness and its wear-resistance. For example, as the ratio （less than 0.1 ） rises up, the hardness and wear-resistance of the film increase because of the formation of TiEN phase. However, as the ratio increases to 0.1 or higher, the hardness and wear-resistance decrease. We suggest that the titanium nitride film, grown on mechanical heart valves made of Ti6Al14V alloy, may significantly improve its wear-resistance of the valve shelf and its service life.