Precision aligned adhesive-free bonding
A major research-led UK university has developed a space-qualified joining technique that allows for precision alignment of the parts being joined. Hydroxide catalysis bonding (HCB) can be performed at room-temperature and produces very thin, high-strength bonds. HCB has many advantages over traditional joining techniques and individual components can be placed and bonded to within a micrometre of the nominal positions.
The precision alignment capability was developed at the University of Glasgow in order to build the optical bench interferometer for the hugely successful ESA Pathfinder mission. HCB is an adaptable, room-temperature process that has many advantages over traditional joining techniques – like epoxy and optical contacting – such as high strength and optical clarity.
Bonding is achieved through the application of an aqueous solution to both surfaces that are to be joined. The solution will then act as a glueless adhesive; silicate networks grow between the parts to create a seamless, ultra-stable, vacuum-compatible joint. The time taken for the join to set can also be controlled to allow for the precision alignment of all parts.
Innovations & Advantages
- High mechanical strength – up to the strength of the bulk material
- Joining of dissimilar materials
- Survives large temperature ranges
- UHV (Ultra High Vacuum) compatible
- Room temperature and atmospheric pressure bonding process
- Components can be placed with extreme precision
- Optically clear with very low absorption – suitable for high power laser transmission
- Space-qualified technology
Current and Potential Domains of Application
HCB is currently used in a wide variety of applications – gravitational wave observatories, space optics, composite optics – and has the potential to be used in many applications that are currently limited by a joining technology.HCB is currently used in a wide variety of applications – gravitational wave observatories, space optics, composite optics – and has the potential to be used in many applications that are currently limited by a joining technology.