Pond, R. B. | Engineering Papers

NASA NTRS1985

Metallic Foams

The formation of metallic foams by use of a blowing agent in the melt was investigated. It was attempted to produce a metallic foam by melting a mixture of Cu powder and graphite in a SPAR rocket. The graphite combines with the oxide on the copper to form Co and acts as a blowing agent. No foam was formed, and it could not be determined whether the foam fails to form, forms but was lost to surface tension instabilities, or is destroyed by incomplete solidification before reentry.

Pond, R. B.↗

NASA NTRS1985

Diffusion in Immiscible Melts

The objective of this program is to measure the diffusion coefficients for molten Pb in Zn in the immiscible liquid-phase region. Diffusion couples of pure Pb and Zn were prepared using a shear cell. These have been placed in graphite crucibles and encapsulated in stainless steel cartridges and are awaiting the next Materials Experiment Assembly (MEA) flight opportunity. In flight, one couple will be soaked for 40 minutes at 440 deg C (just above the monotectic temperature) and the second couple will be soaked for 40 minutes 820 deg C (just above the consolute temperature). After the soak both samples will be rapidly quenched by flowing He to minimize redistribution of the immiscible phases. Post flight compositional analysis will be accomplished using X-ray fluorescence in the scanning electron microscopy.

Pond, R. B.↗