Processing of Syntactic Foams: A Review

Abstract: For structural application different types of lighter material with higher specific strength are being developed now days like honeycomb, metal foam, sandwich panels, syntactic foam etc. In this review paper the syntactic foam is discussed among all these lighter material. Syntactic foams are the materials in which micro spheres are incorporated in a matrix. In syntactic foams, the matrix is reinforced with hollow spherical particles which have a controlled systematic arrangement in the matrix. Hollow microspheres give the syntactic foam its low density, high specific strength, and low moisture absorption. Microspheres may comprise glass, polymer, carbon and ceramic or even metal. The strength of syntactic foams can be nearly equal to that of the matrix. The plateau and yield stress can be tailored over a wide range by selecting appropriate volume fraction and particle type. Metal matrix syntactic foams are expected to have better properties compared to open or closed-cell metallic foams since the former have controlled size and geometry of porosity and the ceramic shells contribute to stiffness and strength. Several preparation methods are used for preparing syntactic foam and various applications are discussed, depending on the types of matrix and reinforcement used. Keywords: Microspheres, Metal foam, Composite, Mold.