Liang Qi, Stanishevsky Andrei, Vohra Yogesh K
Department of Physics, University of Alabama at Birmingham, Birmingham, AL 35294-1170 USA.
Thin Solid Films. 2009 Nov 28;517(2):800-804. doi: 10.1016/j.tsf.2008.08.171.
Undoped and boron-doped nanocrystalline (NCD) diamond films were deposited on mirror polished Ti-6Al-4V substrates in a Microwave Plasma Assisted Chemical Vapor Deposition system. Sliding wear tests were conducted in ambient air with a nanotribometer. A systematic study of the tribological properties for both undoped and boron-doped NCD films were carried out. It was found for diamond/diamond sliding, coefficient of friction decreases with increasing normal loads. It was also found that the wear rate of boron-doped NCD films is about 10 times higher than that of undoped films. A wear rate of ~5.2×10(-9) mm(3)/Nm was found for undoped NCD films. This value is comparable to the best known value of that of polished polycrystalline diamond films. Although no surface deformation, film delamination or micro-cracking were observed for undoped films, boron-doped NCD film undergoes a critical failure at a normal stress of 2.2 GPa, above which surface deformation is evident. Combined with high hardness and modulus, tunable conductivity and improved open air thermal stability, boron-doped nanocrystalline diamond film has tremendous potentials for applications such as Atomic Force Microscope probes, Micro-Electro-Mechanical System devices and biomedical sensors.
在微波等离子体辅助化学气相沉积系统中，将未掺杂和硼掺杂的纳米晶（NCD）金刚石薄膜沉积在镜面抛光的Ti-6Al-4V基体上。使用纳米摩擦计在环境空气中进行滑动磨损试验。对未掺杂和硼掺杂的NCD薄膜的摩擦学性能进行了系统研究。研究发现，对于金刚石/金刚石滑动，摩擦系数随法向载荷的增加而降低。还发现硼掺杂NCD薄膜的磨损率比未掺杂薄膜高约10倍。未掺杂的NCD薄膜的磨损率约为5.2×10(-9) mm(3)/Nm。该值与已知的最佳抛光多晶金刚石薄膜的值相当。虽然未掺杂的薄膜未观察到表面变形、薄膜分层或微裂纹，但硼掺杂的NCD薄膜在2.2 GPa的法向应力下会发生临界失效，高于此应力时表面变形明显。结合高硬度和模量、可调电导率以及改善的露天热稳定性，硼掺杂的纳米晶金刚石薄膜在原子力显微镜探针、微机电系统器件和生物医学传感器等应用方面具有巨大潜力。
