Yin Guangfu, Zheng Changqiong and Luo Jiaoming

Sichuan Union University, Chengdu, 610065, China
suucust@rose.cnc.ac.cn

Since the artificial mechanical heart valve (AMHV) made of metal coated with carbon possesses both the favourite machineability of the metal and the excellent haemo-compatibility of the carbon coating, and can be easily monitored in-vivo by X-radiography, it is becoming more and more favoured by the clinical physicians. In the 1980's, diamond-like carbon (DLC) films coated on valve frames made of titanic alloy or stainless steel have been prepared by means of glow discharge plasma CVD in our laboratory. The results showed that the wear-resistance, corrosion-resistance and haemo-compatibility of the prepared composite material had been remarkably improved than those of uncoated metallic materials, so it is possible to make full metallic substrate AMHV (both valve frame and leaflet ) coated with DLC film. However, the DLC film sometimes peeled off from the metal substrate after deposition or during the thermal expansion assembly process. It may be due to the great difference of the thermal expansion coefficient between the DLC film and metal substrate, thus a thermal stress would generate, which was great enough to cause the DLC film peel off from the substrate during the thermal shock.

In this study, a new kind of Ti-TiC-C gradient biomaterial has been prepared by means of plasma source ion implant - ion beam enhanced deposition (PSII-IBED). The experimental results showed that the involved components could be controlled to distribute gradually along the depth through changing implant and deposition condition. As the result, the intrinsic stress and thermal stress would be remarkable reduced, and the adhesive strength could be greatly increased. The gradient biomaterial made by PSII-IBED can meet the needs of AMHV.

*The project is supported by the National Science Foundation of China