氮化硅陶瓷刀具表面涂覆高硬耐磨氮化钛涂层研究

Study on the Preparation of Hard and Wear-resistant Titanium Nitride Films on Silicon Nitride Ceramic Cutting Tools

用高能量密度脉冲等离子体于室温下在氮化硅陶瓷刀具上成功沉积了高硬耐磨的氮化钛涂层。薄膜厚度用光学显微镜和俄歇电子能谱仪测定,薄膜元素和相组成与分布分别用俄歇电子能谱仪、X光电子能谱以及X光衍射仪测定,薄膜微观结构用扫描电镜观察,薄膜表面粗糙度用光学显微镜测定,薄膜力学性能由纳米压痕实验和纳米划痕实验确定,薄膜的磨损性能用工业条件下的切削实验评价。实验结果表明,在最优化条件下,涂层与基体的结合力很好,纳米划痕实验临界载荷达80 mN以上;氮化钛涂层具有很高的硬度和杨氏模量,分别达28 GPa和350 GPa以上。涂层刀具用于HB达2 200 MPa^2 300 MPa的HT250钢切削实验表明,刀具耐磨损能力增强,寿命明显提高。

Hard and wear-resistant titanium nitride coatings were deposited by pulsed high energy density plasma technique on silicon nitride ceramic cutting tools at ambient temperature. The coating thickness was measured by an optical profiler and surface Auger microprobe. The elemental composition and depth concentration profiles, phase compositions and elemental binding states of the coatings were determined by Auger microprobe, x-ray photon-electron spectroscope, and X-ray diffractometer. The microstructures of the coatings were observed by scan electron microscope and the roughness of the sample surface was measured by an optical profiler. The mechanical properties of the coatings were determined by nanoindentation and nanoscratch tests. The tribological properties were evaluated by the cutting performances of the coated tools applied in turning of HT250 steel under industrial conditions. The structural and mechanical properties of the coatings were found to depend, strongly on synthetic conditions. Under optimized deposition conditions, the adhesive strength of TiN film to the substrate was satisfactory with the highest critical load up to more than 80 mN. The TiN films possess very high nanohardness and Young's modulus, which are near to 28 GPa and 350 GPa, respectively. The wear resistance and edge life of the silicon nitride ceramic tools were improved dramatically because of the deposition of titanium nitride coatings.