Low Pressure Cold Spray and Reaction Sintering of Intermetallic Metal Matrix Composite Coatings

Recently a Fe-Al, Ti–Al, Ni-Al and other metal–intermetallic laminate (MIL) composite coatings attract growing attention because they have potential application in honeycomb or sandwich components of airplanes, thermal barrier coatings in diesel engines, and as biomaterial with good bio-compatibility. Of the available processing techniques, diffusion bonding of elemental titanium, nickel, iron and aluminum foils is an effective low-temperature method to synthesize the composite, allowing growth of the intermetallic layer. The task of this paper is to define microstructural changes of metal–intermetallic laminate composite coatings during low pressure cold spraying and reaction sintering. The optical microscopy, SEM, EDS, X-ray and microhardness examinations will be presented and analysed. Possible applications of cold spray – reaction sintering technology will be discussed.