Aluminum Nitride, a Refractory for Aluminum to 2000°C.

Abstract

In commercial practice, where temperatures are low, a number of commercially available materials are satisfactory as a container for molten aluminum. None of these, however, resists attack by aluminum in the temperature range 1800' to 2000'C. An investigation was conducted to find a material completely inert to aluminum at these high temperatures. Aluminum nitride emerged as the material that was inert to aluminum and showed satisfactory properties as a ceramic material. A method of preparing high-purity AlN by striking a d.-c. arc between two high-purity aluminum electrodes in a nitrogen atmosphere is described. A refractory having excellent strength and low porosity was achieved by hydrostatic pressing and firing at high temperatures. The mechanical, electrical, thermal, and chemical properties of the refractory are discussed.

The course of the hydrolysis and the reaction kinetics of AlN powder in diluted aqueous suspensions

“…Aluminum nitride (AlN) powder was synthetically produced for the first time in the 19th century, by heating aluminum turnings in an atmosphere of nitrogen at around 700 • C. 1 AlN, like aluminum, 2 is water sensitive 3 and in the presence of water it slowly degrades, forming aluminum hydroxides and ammonia by the following general reaction: 4 AlN + 3H 2 O → Al(OH) 3 + NH 3 (1)…”

Thermodynamic Routes to Novel Metastable Nitrogen-Rich Nitrides

“…7 Nitrides are a particularly compelling class of materials to explore computationally, 8−11 as they are rare in nature and difficult to synthesize in the laboratory. They also have significant technological relevance, as the unique bonding characteristics in nitrides yield electronic structures that range from metallic to semiconducting, producing materials with properties relevant to applications spanning refractory ceramics, 12,13 superconductors, 14,15 solid-state lighting, 16,17 photovoltaics, 18,19 photocatalysts, 20,21 thermoelectrics, 22,23 piezoelectrics, 24,25 permanent magnets, 26 and more.…”

Synthesis of an aluminum nitride–yttria (AlN–Y2O3) composite from nano-sized porous AlN and YCl3

“…Along with these prominent characteristics, AlN melts and breaks down into Al and N at high temperatures (2,200-2,450°C), since it is highly stable from an energetic point of view with strong covalent bonding [4]. Since AlN is a covalently bonded substance, it has a low diffusivity and requires a high temperature for sintering [5]. The thermal conductivity of AlN is sensitive to its crystal structure and depends substantially on impurities, particularly residual oxygen in the structure [6].…”