Precision Brazing for Critical Assemblies
Precision vacuum brazing is routinely used to join critical assemblies that often employ delicate or intricate features. Materials joined include titanium, copper, stainless steel, ceramics, aluminum, steel, tungsten carbide, and tungsten.
- A wide range of experience in materials joining enables us to use the best process conditions for the assembly applications
- When beneficial, a partial pressure braze technique is used to limit sublimation or evaporation of braze filler metal.
- Products that are manufactured include sensors, detectors, cathodes, cold plates, heat exchangers, and biomedical assemblies
VPE Capabilities for Vacuum Brazing Include:
- Assembly weights to 10,000 pounds
- Size greater than 4 feet in diameter and to 100 inches in length
- Temperatures range to 1800° C
- Reactive materials brazing
- Active metal brazing of ceramics
Vacuum brazing employs vacuum as an ambient atmosphere that the components being brazed will not react with excessive oxygen, moisture, nitrogen or other gaseous contaminants. By limiting the reactions with the surrounding atmosphere, we can create a clean environment which is conducive to filler alloy wetting and flow onto metal surfaces and into capillary joints.
The vacuum environment can also reduce surface contamination from oxides and other compounds through sublimation of the species due to chemical reduction. Maintenance of a clean vacuum is essential to production of contaminant-free brazes. Often cryogenic or turbo molecular pumping is used to assure the brazing environment is free of excessive hydrocarbons from the vacuum pumping system.
In vacuum brazing the filler alloy is preplaced on the assembly in such a location that as the furnace temperature is raised and the filler metal alloy melts, it flows into the assembly capillary joints affecting a good bond.
Typical vacuum levels achieved during brazing are 1E-5 to 1E-6 Torr and much higher vacuums are used in several other reactive metal applications. In some applications, a partial pressure of an inert gas is used to mitigate the volatilization of filler metals or parent materials. These partial pressures range from about 1 to 10 Torr.
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