Metal Matrix Composites Produced by Spray Codeposition

A new technique for producing metal matrix particulate composites, consisting of the spray deposition of the metal matrix and the particles, is described. The deposit is removed from the substrate and hot rolled to produce composite strip for examination and testing. It is shown that up to 36 vol.-% of SiC, Al203, chilled iron, graphite, and sand particles, and mixtures of these, 75–120 μm in size, can successfully be incorporated in aluminium and Al–5Si alloy matrixes. The friction properties of some of the composites were shown to be particularly promising. High coefficients of friction of ∼0·6 were obtainable under dry contact conditions, and these were remarkably constant with time. The friction properties compared very favourably with conventional asbestos based and sintered friction materials which showed lower coefficients of friction that increased with time. PM/0310