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Aluminium assembling

2000

I am a french metallurgist engineer and I was asked in my professional field if it was possible to make an assembling of aluminium plates by first a copper coating (like CVD, PVD or CVI) and second an interdiffusion by a heating treatment in a furnace (at not too high temperature because the Aluminium would loose at least 50% of its mechanical properties).

Is it possible and had some company ever tried and succeeded in such a way ?

In advance thanks for response

Xavier Cabirol, a french engineer very curious about "exotic" processes ...

Xavier CABIROL
Cirtes - Saint-DiÈ, France, Europe

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The "liquidus" (spelling?) temp of copper is much higher than the point where copper precipitates out of aluminum, destroying the strength. You might be able to copper plate followed by mechanically spreading a low temp alloy like a solder mixture of an appropriate alloy, not just tin- lead or silver-tin and heat that to below the precipitation temp and achieve a satisfactory bond.

Some honeycomb aircraft wings are glued together (T-38 for example), which might be a possibility after phosphoric anodizing the aluminum.

James Watts
- Navarre, Florida
2000

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Xavier, Silver is a good material for low-temperature solid phase bonding. Oxides will dissolve into the silver from the interface. PVD silver on beryllium has long been used to diffusion bond precision parts. If you use solders beware of grain boundry embrittlement. Don Mattox

Donald M. Mattox
Society of Vacuum Coaters
Albuquerque, New Mexico 2000

Don is correct about silver and his caution on "solder". Unfortunately, silver also melts higher than the copper precipitation temperature.

James Watts
- Navarre, Florida
2000

James, You don't need to melt the silver for solid state diffusion bonding - just heat and pressure or ultrasonics. Don Mattox

Donald M. Mattox
Society of Vacuum Coaters - Albuquerque, NM
2000

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Hi Don,

That is a new one on me, which makes me very interested. What is an ideal temp and pressure? Can they be interchanged--Higher pressure= less temperature? Jim

James Watts
- Navarre, Florida
2000