Formation Mechanism of AlN–SiC Solid Solution by Combustion Nitridation in Si₃N₄–Si‐Al‐C System

Abstract

The synthesis of solid solutions of AlN-SiC was investigated through the combustion reaction between Si 3 N 4 , aluminum, and carbon powders and nitrogen gas at pressures ranging from 0.1 to 6.0 MPa. The combustion reaction was initiated locally and then the wave front propagated spontaneously, passing through the cylindrical bed containing the loose powder. In the presence of Si 3 N 4 as a reactant, it was feasible to synthesize solid solutions at an ambient pressure (0.1 MPa). The relationship between nitrogen pressure and full-width at half-maximum of the (110) peak of the product showed that lower pressures produced more-homogeneous solid solutions. Some aspects of formation of the AlN-SiC solid solutions were discussed with special emphasis on the influence of nitrogen pressure and reactant stoichiometry.

Electrical and thermal properties of SiC–AlN ceramics without sintering additives

“…AlN is known as a sintering additive that increases the density of SiC by enhancing the diffusivity of Si and C [37,38] and by forming 2H ss during sintering [18][19][20][21]. The present study Table 1 Batch composition, relative density, and phase analysis results of hot-pressed SiC ceramics.…”

“…In contrast, AlN ceramics exhibit generally higher thermal conductivity and better electrically insulating properties but relatively poor mechanical properties [11][12][13][14][15][16][17]. It is well known that AlN and SiC form solid solutions with a wide range of compositions [18][19][20][21]. Applications for a substrate material in power electronics require higher thermal conductivity, higher electrical resistivity, and better mechanical properties.…”

“…Since the first report on the formation of a 2H solid solution (2H ss ) between SiC and AlN by Cutler et al [18], intensive research has been performed over the last three decades to elucidate the properties of 2H ss and further improve the mechanical properties of the 2H ss and the SiC-AlN ceramics [18][19][20][21][22][23]. The mechanical properties obtained in optimized SiC-AlN ceramics included a strength of 800 MPa, a fracture toughness of 7 MPa m 1/2 , and a hardness of 20 GPa at room temperature [23][24][25].…”

Field Activated Combustion Synthesis of Ceramic and Composite Materials

“…Solid solution synthesis was also accomplished using a solid as well as a gas as a source of nitrogen (Si3N4 + C + Al +N2) [9]. In contrast to the case in which the nitrogen source is gaseous, the use of SiaN4 made possible the formation of solid solutions at ambient nitrogen pressure.…”

Combustion synthesis of hexagonal AlN–SiC solid solution under low nitrogen pressure

“…Xue and Munir [9] fabricated the solid solution via reaction between silicon nitride (Si 3 N 4 ), Al, and C powders under an electric field. Using Si 3 N 4 as a reactant, they demonstrated that solid solution could be produced in a self-sustaining combustion regime under an ambient nitrogen pressure (0.1 MPa) without an electric field [1]. Other schemes included combustion of powder mixtures of Al, Si, and carbon in nitrogen [10,11].…”