A method for producing nanowires from piezoelectric aluminum nitride is provided. Nanowires formed from cubic AIN having a diameter of 10-20 A and a length of 1000-1500 A are obtained from a batch of AI+2-10% by volume AIH3 at a temperature of 1500-2300 K in a gaseous environment of N2+(3-5% by volume NH3) at a pressure of 200-2000 MPa.

A molten iron-assisted method for producing aluminum nitride (AlN) and a device thereof are disclosed. Pure aluminum is introduced into a vacuumed molten iron bath continuously for producing a molten iron bath having the aluminum, then nitrogen is introduced into the molten iron bath having the aluminum. Production of AIN is controlled by having the concentration of aluminum in the molten iron bath having the aluminum controlled. At the time AIN is formed continuously in the molten iron bath having the aluminum, AIN floats to the surface of the molten iron bath having the aluminum. Ar and N.sub.2 may be blown and dust is removed by static electrons thereafter, such that pure aluminum nitride powder can be collected. Finally, the used gas is recycled and reused.

Porous aluminum nitride (AlN) provides a greater surface area and higher permeability, which is especially desirable for advanced functional application. Porous or bulk aluminum nitride is very difficult to manufacture due mainly to its high melting point (e.g., 2200 degrees Celsius). A new processing method synthesizes porous aluminum nitride through a complete transformation from porous aluminum using a remarkably low nitriding or sintering temperature. The manufactured porous aluminum nitride foam can be used for such applications as filters, separators, heat sinks, ballistic armor, electronic packaging, light- and field-emission devices, and highly wear-resistant composites when infiltrated with metal such as aluminum, titanium, or copper.

A method for producing AlN crystals includes using at least one element, excluding Si, that satisfies a condition under which the element forms a compound with neither Al nor N or a condition under which the element forms a compound with any of Al and N provided that the standard free energy of formation of the compound is larger than that of AlN; melting a composition containing at least Al and the element; and reacting the Al vapor with nitrogen gas at a predetermined reaction temperature to produce AlN crystals.

An aluminum nitride plate satisfies both of a relation 1: c1>97.5% and a relation 2: c2/c1<0.995 where c1 is a c-plane degree of orientation that is defined as a ratio of a diffraction intensity of (002) plane to a sum of the diffraction intensity of (002) plane and a diffraction intensity of (100) plane when the surface layer of the aluminum nitride plate is subjected to an X-ray diffraction measurement, and c2 is a c-plane degree of (002) plane to the sum of the diffraction intensity of (002) plane and the diffraction intensity of (100) plane when a portion other than the surface layer of the aluminum nitride plate is subjected to the X-ray diffraction. Moreover, in the aluminum nitride plate, a difference in nitrogen content between the surface layer and the portion other than the surface layer is less than 0.15% in weight ratio.

To produce aluminum nitride in the form of a lump that can easily be broken down by light pulverization, which could not be obtained by a conventional combustion synthesis method. A method for producing aluminum nitride powder by a combustion synthesis method using a metallic aluminum powder, characterized in that a powder mixture in which an aluminum nitride powder having an average primary particle diameter of 3 m or less as a diluent is mixed with a metallic aluminum powder in a ratio of 150 to 400 parts by mass of the aluminum nitride powder relative to 100 parts by mass of the metallic aluminum powder, is ignited to combust in a nitrogen atmosphere.

Porous aluminum nitride (AlN) provides a greater surface area and higher permeability, which is especially desirable for advanced functional application. Porous or bulk aluminum nitride is very difficult to manufacture due mainly to its high melting point (e.g., 2200 degrees Celsius). A new processing method synthesizes porous aluminum nitride through a complete transformation from porous aluminum using a remarkably low nitriding or sintering temperature. The manufactured porous aluminum nitride foam can be used for such applications as filters, separators, heat sinks, ballistic armor, electronic packaging, light- and field-emission devices, and highly wear-resistant composites when infiltrated with metal such as aluminum, titanium, or copper.