TriMetal Transitions
TriMetal transitions are used to provide the reliable all-metal seal of the standard stainless steel CF flange on aluminum vacuum chambers. TriMetal is an explosively bonded material made up of three metals. Aluminum and stainless steel are joined together with an interlayer. From this material, transitions are made for integrating stainless steel and aluminum components on vacuum systems. TriMetal transitions and flanges eliminate the risk of leaks associated with using aluminum-to-aluminum or aluminum-to-stainless steel flange assemblies on aluminum chambers.
Explosive Bonding
Explosive bonding is an effective means of joining dissimilar metals. The high pressure of the explosion creates an abrupt, uniform metallurgical bond at the interface of the joined metals. The bonded material retains each of the bonded metals’ initial physical and mechanical properties.
Diffusion bonding, roll bonding and brazing all fall short of the quality of an explosive bond. In these other metal-joining processes, areas of the transition may form brittle intermetallic layers or there may be unpredictable areas of void in the bond line. In UHV components, the inconsistencies in this type of bonded material can become leak failures. Explosively bonded material–with its strong uniform bonds–will not leak and therefore is an excellent choice for integrating components of various metals in a vacuum system.
TriMetal Flanges
The TriMetal flange is a standard stainless steel CF flange with the TriMetal transition attached. The aluminum end is ready to be welded directly to an aluminum chamber. The stainless steel flange end is ready to be mated to another standard stainless steel CF flange. Each TriMetal transition is thermally cycled to over 300°C, then helium leak-tested to a sensitivity of 5 x 10-10 std cc He/sec. PyraFlat flanges are Thermionics’ line of rectangular and odd-shaped all-metal flanges. PyraFlat flanges employ the same reliable sealing principle as CF flanges. The PyraFlat flange has been used successfully at synchrotron facilities for over 10 years.
TriMetal PyraFlat Flanges
TriMetal transitions are available for attachment to PyraFlat flanges. This allows the use of the reliable seal of the standard stainless steel PyraFlat flange assembly for rectangular ports on aluminum beamlines or chambers.