浮上窒化反応による高純度AlN粉末の合成

概要

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A pure AlN powder was synthesized continuously at 1150-1500℃ by the floating nitridation technique. The nitriding temperature was reduced about 200℃ by us ing N_2 as fioating gas for Al powder and injecting an N_2/NH_3 gas mixture at the center of the heating zone. The AlN powder obtained at 1300℃ had a size of about 10 μm and specific surface area of 24.2 m^2/g. AlN parti cles were so brittle that they were easily crushed to be low 0.1 μm. This AlN powder had good flowability and sinterability, and transparent AlN ceramics were ob tained by hot pressing at 1900℃ without any sintering aids. A percentage conversion decreased rapidly with increase in NH_3 concentration when an N_2/NH_3 gas mixture was used as floating gas. The nitriding rate de pended strongly on the cracks formed on the particle surface, but not on the diffusion of nitrogen through the surface AlN Iayer.
社団法人日本セラミックス協会の論文
1994-11-01