Abstract Scope |
The traditional lubricating materials used in space have limited lifetimes in vacuum due to the catalytic degradation on metal surfaces, high vaporization at high temperatures, dewetting, and other disadvantages. The lubricants for the space applications must have vacuum stability, high viscosity index, low creep tendency, good elastohydrodynamic and boundary lubrication properties, optical or infrared transparency, and radiation atomic oxygen resistance. The addition of nanosize particles is one of the methods to enhance the thermophysical and heat transfer properties of liquid lubricants. Some of these properties for liquid lubricants are volatility, creep, surface tension, viscosity, chemical composition, weight loss, density, vapor pressure, etc. The rheological and heat and mass transfer measurements for newly developed nanolubricants were conducted using Differential Scanning Calorimetry (DSC), rotational rheometer of “parallel-plates” mode and Thermogravimetric Analyzer (TGA). |