Plasma Synthesis of Aluminum Nitride Nanopowders

Aluminum nitride is as an ideal thermal management material since it has a very high thermal conductivity and its electrical resistivity is comparable to that of ceramic insulators. Aluminum nitride has thermal conductivity five times greater than alumina and has mechanical strength twice that of alumina and beryllium oxide. The current methods of synthesizing and consolidating aluminum nitride results in higher percentage of impurities which affects the thermal and mechanical properties of the material. Oxygen is one of the major impurities which occurs because of the synthesis technique adopted as well as the limitations in the present consolidation techniques to remove or rupture the oxide layer during consolidation. In this Phase I effort, MMI proposes to synthesize and consolidate nanopowders of aluminum nitride with cantly lower percentage of impurities. Nanocrystalline AIN powders will have the advantage of densifying at much lower temperatures and pressures and can easily be formed into shapes due to their ability to be superplastically deformed. AIN nanopowders will be synthesized using the plasma chemical synthesis (PCS) technique while the consolidation will be done using the plasma-pressure consolidation (PPC) technique. Plasma chemical synthesis of synthesizing nanopowders is expected to result in high purity alloy powders with a narrow size distribution, when compared to DC or induction plasma technique. The plasma pressure consolidation technique is expected to result in parts with near theoretical density without the use of any sintering aids. Anticipated Results: Novel technique of synthes zing and consolidating AlN nanocrystalline powders. Applications: Electronic substrates, Adhesives, Metal matrix composites, electrical insulators, power transistors, furnace fixtures, arrnor material.