Production of Aluminum Foams with Ni-coated TiH2 Powder

In this study the powder metallurgical route was employed to produce aluminum foams using 1%wt of Ni-coated TiH(2) powders as foaming agent. The powders were coated by an electroless coating technique. It was found that nickel coatings on catalyzed TiH(2) powders produce a further delay on the hydrogen evolution behavior as compared to TiH(2) powders previously surface oxidized at 500 degrees C. The original temperature mismatch is reduced by more than 70 degrees C without compromising the amount of hydrogen remaining in the powders needed to produce the foam expansion. Al-foams produced from Ni-coated TiH(2) display a narrower pore size distribution and consequently are more homogeneous than the ones produced with unmodified TiH(2) powders. Moreover the reproducibility of the foam characteristics is enhanced.