Friction and wear performances of hot filament chemical vapor deposition multilayer diamond films coated on silicon carbide under water lubrication

Tribological properties of chemical vapor deposition (CVD) diamond films greatly affect its application in the mechanical field. In this paper, a novel multilayer structure is proposed, with which multilayer diamond films are deposited on silicon carbide by hot filament CVD (HFCVD) method. The different micrometric diamond grains are produced by adjusting deposition parameters. The as-deposited multilayer diamond films are characterized by scanning electron microscope (SEM) and white-light interferometry. The friction tests performed on a reciprocating ball-on-plate tribometer suggest that silicon carbide presents the friction coefficient of 0.400 for dry sliding against silicon nitride (Si₃N₄) ceramic counterface. With the water lubrication, the corresponding friction coefficients of silicon carbide and as-deposited multilayer diamond films further reduce to 0.193 and 0.051, respectively. The worn surfaces indicate that multilayer diamond films exhibit considerably high wear resistance.     

等离子化学气相沉积（PCVD）TiN涂层的组织与性能研究

本文用透射电镜和x光衍射仪揭示了PCVD法TiN涂层的物相及超细晶粒、位错、择优取向等微观结构，并对该涂层的性能进行了比较试验。     

Effect of Gr Content and Hot Extrusion on Tensile Properties of （Nano-SiCp~-Gr）/Cu Composites Fabricated by Powder Metallurgy

Novel hybrid Cu matrix composites reinforced by graphite (Gr) particle with volume fraction of 5%?C15% and nano-SiC particle (nano-SiCp) with volume fraction of 3% have been prepared by powder metallurgy. The results show that Gr and nano-SiCp distribute uniformly in the Cu matrix. With increasing the volume fraction of Gr, the tensile strength of the composites decreases from 114 to 51MPa and the elastic modulus decreases from 75 to 60GPa. Compared with the sintered composites, the tensile properties including elastic modulus, tensile strength, yield strength and tensile elongation of the hot-extruded (nano-SiCp+Gr)/Cu composites are improved greatly due to higher relative density of the composites and more uniform distribution of Gr and nano-SiCp, in addition to finer grain size of the matrix as a result of dynamic recovery and recrystallization which occur during hot extrusion process.