Chemical bonding of ultra low expansion glass substrates with aqueous NaOH solution

We report on our research towards determining a reliable and reproducible method of bonding ULE® components for space-based instruments. Such bonded components are required to withstand considerable accelerations during launch and can be exposed to significant temperature variations. The results of tensile and shear testing of a large number of bonded samples are reported, as well as the impact of thermal cycling on bond strength. A study on the feasibility of de-bonding and re-bonding ULE parts is also described.

► Optical contacting maintains optical tolerances of glass assemblies.
► Catalytic bonding creates strong bond between glass parts.
► Bond strength is enhanced by baking components.
► Breaking stress and bending strength thresholds sufficient for space usage are reached and exceeded; Weibull modulus similar to bulk glass.
► Thermal cycling does not affect the bond strength.
► De-bonding and re-bonding are possible within a time window of several hours.