Synthesis of AlN Polytypoid through the Exothermic Nitridation of the System Al-AlN-SiO₂

抄録

AlN polytypoids composed of Al, Si, O and N can be obtained from the AlN-SiO₂. In general, the polytypoids have been fabricated by firing the powder mixture of AlN and SiO₂ in N₂ atmosphere. In this study, we proposed a new idea to synthesize the polytypoids using the exothermic reaction appeared during firing the Al-AlN-SiO₂ in N₂ flow. High purity Al, AlN and SiO₂ powders were used as raw materials. Various compositions of powder mixtures to form 27R-polytypoids were fired at 700 and 800^oC in N₂ flow. The polytypoids were not synthesized by firing the Al-SiO₂, because the reaction of Al + SiO₂= Al₂O₃ + Si was preceded. However, by the addition of AlN to the Al-SiO₂, 27R-polytypoid with very fine particle size below 100nm was successfully synthesized through the exothermic nitridation-reaction, which means AlN particles prevented Al particles from contacting SiO₂ particles.