钛激光气体氮化改性种植体的研究

Laser surface modification of medical titanium

目的利用激光气体氮化工艺在医用纯钛表面制备TiN改性层,增强医用钛的表面性能,测试改性层的组织、成分和硬度。方法采用2 kW Nd:YAG激光器对置于特制导光可控气氛反应室中的医用纯钛辐照,在纯度为99.995%的氮气中进行激光气体氮化过程。测试分析材料改性前后的显微组织、成分和硬度。结果在医用钛的表面制备了厚度约400μm的TiN梯度改性层,氮化层与基体界面呈良好的冶金结合。沿着改性层截面方向,显微硬度逐渐减小。结论采用激光气体氮化技术可以在医用钛表面制备致密的TiN增强金属复合材料梯度氮化层,氮化层内部TiN增强相呈梯度分布。

Objective Titanium, by far one of the oldest materials in medical implants used for hard tissue replacement and rehabilitation, was used widely as implant material. The objective of the present study was to fabricate the TiN modified layer on the surface of medical pure titanium and improve its surface properties. Thus the wear resistance, biocompatibility and antisepsis were improved. Methods A continuous-wave 2 kW Nd：YAG laser was used to irradiate the sample in the environment of N2 with concentration of 99.995%. Titanium nitride surface coatings had been extensively used as corrosion resistant and biocompatible layers on titanium and its alloys. The microstructure and composition of the laser nitrided coating were studied by scanning electron microscopy and X-ray diffraction. Microhardness of the modified sample was also analyzed by micro-hardmeter. Results TiN modified layer with the thickness of about 400 μm was obtained. TiN distributed gradually from surface to the substrate. There was a good metallurgical bonding between the nitrided layer and the substrate. The hardness of the modified layer was reduced from the surface to the inside. Conclusion With optimum process parameters, a compact laser modified gradient coating reinforced with fine TiN was achieved on the surface of medical titanium.