Two‐Step Carbothermal Synthesis of AlN–SiC Solid Solution Powder Using Combustion Synthesized Precursor

Abstract

In the present work, a two-step carbothermal reduction method is employed to prepare the AlN-SiC solid solution (AlN-SiCss) powders by using a combustion synthesized precursor. The precursor is prepared by low-temperature combustion synthesis (LCS) method using a mixed solution of aluminum nitrate, silicic acid, polyacrylamide, glucose, and urea. The synthesized LCS precursor exhibits a porous and foamy uniform mixture of Al 2 O 3 + SiO 2 + C consisting of flaky particles. The carbothermal reduction in the LCS precursor is carried out in two steps. First, the precursors are calcined at 1600°C in argon for 3 h. Subsequently, the precursors are further calcined at 1600°C-1900°C in nitrogen for 3 h. The results indicate that the precursor calcined at and above 1850°C in nitrogen for 3 h yields the single-phase AlN-SiCss powders. The synthesized AlN-SiCss powder exhibits nearspherical particles with diameter of 200-500 nm. The experimental and thermodynamical results reveal that the formation of AlN-SiCss occurs via the diffusion of AlN into SiC by virtue of formation of a highly defective b 0 intermediate during the second step reaction.

Thermal Conductivity and High-Frequency Dielectric Properties of Pressureless Sintered SiC-AlN Multiphase Ceramics

“…Those properties, along with its nontoxic characteristics, make AlN a popular substrate material instead of BeO. AlN and SiC also can form a solid solution under certain conditions [ 13 ], which can largely improve the sintering activity, mechanical properties, electrical conductivity, and oxidation resistance of materials [ 14 , 15 , 16 ].…”