Foams on the Cutting Edge

This article focuses on how manufacturers have pushed the limits of plastic, glass, and other materials by turning them into sturdy foams. Materials created by mixing a solid with minute spheres of glass ceramic, or polymer are finding an increasing range of uses in industrial and high-tech applications. Microspheres, both solid and hollow, have wide commercial uses. Polymer microspheres appear in the medical, pharmaceutical, and cosmetics industries, for applications ranging from blood circulation tracers in research, to time-release capsules in medicines, to facial oil absorbers in makeup. At Northeastern University in Boston, Teiichi Ando is producing metallic microspheres to investigate various metallurgical phenomena. When the spheres are subjected to extremely high cooling rates, they can form as metallic glasses, supercooled metals that have not crystallized. The resulting spheres are free of grain boundaries and other flaws. Syntactic foam ingots of various alloys have been produced using moderate pressure infiltration of silica-alumina spheres.