REACTIVE PLASMA SPRAY FORMING FOR ADVANCED MATERIALS SYNTHESIS

The economic production of wear-resistant materials and advanced composite structural materials is of growing importance. Fiber, particulate, or intermetallic reinforced metal or ceramic matrices are all proposed for use in many varied applications, ranging from aircraft components, biomedical implants, to automotive engines. The acceptance of such hard materials or composites with Ni3Al or TiAl with SiC or Al2O3 fibers or particles, titanium alloys with carbide reinforcement, alumina or zirconia with SiAlON fibers, phase toughened MoSi2 with SiC dispersions, or aluminum alloys with ceramic particulate reinforcement all depend on viable and economic production methods. Reactive plasma spray processing is being investigated as a method by which to produce such materials and is already finding application in the production of wear-resistant materials, advanced composites, diamond, and high T(c) oxide superconductors. In these processes, the reactive thermal plasma state produces new phases, even as reinforcements in matrix materials, starting with particulates, liquids, and/or gases. This paper reviews recent investigations into the production of intermetallic alloys, composite materials such as TiAl, Ti/TiC, Ti/TiN, Mo/MoSi2, MoSi2/SiC, and Al2O3/SiAlON by reactive plasma spraying in controlled atmospheres. Research on diamond and high T(c) oxide superconductors is also discussed. In addition, the advantages, limitations, and research needs for this emerging technology are presented.