水素フリーカーボン系薄膜のナノ構造変化による 境界潤滑特性の向上に関する研究(博士論文概要)水素フリーカーボン系薄膜のナノ構造変化による 境界潤滑特性の向上に関する研究(博士論文概要) Improvement of the boundary lubrication properties of hydrogen-free carbonaceous thin films by changing the nanostructure(Outline of Doctor Thesis)
In this study, we discuss the present situation of research of boundary lubrication properties, the friction reduction model, diamond, DLC, and nanoperiod multilayer films. The purpose of this research is also discussed. To reduce the friction coefficient under boundary lubrication, polished chemical-vapor-deposited diamond films have been surface modified by fluorination, oxidation, and nitrogen ion implantation. The friction coefficient dependence on the surface free energy of the surface-modified diamond films has been clarified. Hydrogen-free DLC films have been deposited by the bend filtered cathodic vacuum arc (FCVA) technique under a boundary lubricated FCVA-DLC film using deposited with a proper DC bias voltage, and the films show low friction coefficients. The boundary lubrication properties of various metal-containing hydrogen-free sputtered DLC films have been investigated using a ball-on-disk tribometer and compared with those of diamond and FCVA-DLC films. DLC films containing an appropriate amount of Co have the lowest friction coefficient of μ = 0.02 among all of the tested films. The low-friction and low viscoelastic tribo-products formed on the sliding surface of Co-containing DLC films were observed by atomic force microscopy with force modulation methods. To develop a new low friction and wear resistant coating, nanometer period (TiC/DLC)n multilayer films composed of titanium carbide and hydrogen-free DLC layers were deposited. The 12-nm-target-period multilayer (TiC/DLC)n film has the shortest period and the largest number of interfaces that prevent damage elongation. This film also has superior nanowear resistance and boundary lubrication properties. To develop an electroconductive and high-endurance solid lubricant composed of hydrogen-free DLC, gold layers were deposited while. (DLC/Au)n films also have a lower friction coefficient and exhibit less damage than Au monolayer film under PAO boundary lubrication. To develop low surface-free energy and electroconductive solid lubricant film multilayers, mixed films composed of gold, which has high electrical conductivity, and polytetrafluoroethylene (PTFE), which has a low surface energy, were deposited. The multilayer films have a low surface energy, low electrical resistance, low friction, and long-time endurance.