Joselito

[Joselito]

I have an interesting problem. I am doing work with boral, which is a sandwich material composed of a sintered layer of aluminum and Boron Carbide with a thin layer of aluminum attached on the top and bottom surfaces by hot rolling.

The test coupons being used are allowed to soak in baths of demineralized water at moderately high temperatures and pressures (150 F, 18 psi-g) for aproximately 140 hours. A water retention weight gain of aproximately 0.40 % is observed before the coupons are placed within a high temperature vacuum vessel (550 F, 0.09 psi-a).

As the coupons are heated the absorbed water vaporizes and tries to escape. In doing so, blisters are created in the aluminum outer coating in a small number of trial coupons but not in others.

I am trying to determine what properties of this material is affecting blister formation. Does anyone think that the demineralized water is corroding the material once it has been absorbed and is blocking itself in?

Thanks for any help.

 

[mcguire]

I had the same problem with powdered aluminum alloy sandwiched between two layers of wrought aluminum. Water adsorbed on the great surface area desorbs on heating.
You have to find a way to let this get out.