Vacuum Providing in Devices with Internal Adhesive Joints

One of the main objectives during the design of electro-micromechanical devices, given their small weight and size characteristics and small gaps between mechanical parts, is to ensure a high vacuum in the housing. The residual gas causes, in particular, an additional vibration damping of vibrating gyroscopes resonators and significantly affects their performance data. Manufacture of micromechanical devices can be significantly simplified by using glue to connect disparate parts of metallic and nonmetallic materials. Glue securely connects the parts and provides uniform distribution of stress on seams. The main disadvantage of the adhesive joints is the emission of volatile components in vacuum, leading to deterioration of the characteristics of the vacuum unit. In this regard, small outgassing is one of the main technological requirements imposed on the glue. In this work, outgassing from the cured epoxy adhesive EPO-TEKH74UNF is investigated. Degassing in vacuum at high temperatures reduces the outgassing specific rate by some orders of magnitude. Based on these results a model of the outgassing of this glue is considered. Degassing of adhesive joints and the use of gas absorbent (getters) allows creating vacuum devices with internal glue joints whose residual gas pressure is equal to or less than 10^-4 Pa.

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