ABSTRACT
The selection of materials and components in vacuum practice is primarily governed by the applications and the pressure range. The glass systems can be conveniently used for experimental studies involving small volumes. Lower outgassing rates, higher chemical stability, excellent electrical resistivity, high thermal shock resistance and lower coefficient of thermal expansion are important characteristics that makes glass suitable for UHV applications. Limitations of glass include its fragility, inability for bakeout at temperatures higher than 450°C, deterioration of insulating properties at high temperatures and inability to construct large (>10 liters) volume chambers. Most UHV systems for experimental studies involving interaction with clean solid surface need to use bakeable components. Stainless steel Type 304 is the most suitable material of construction. Aluminium alloy Al 6061-T6, OFHC copper are also are used for some applications. Moybdenum disulphide (MoS2) powder with particle sizes in the range 1 to 100 µm is suitable as a lubricant in vacuum environment. Hilton and Fleischauer1 have discussed the lubricants for high vacuum applications.
