Fabrication of novel AlN-SiC-C refractories by nitrogen gas-pressure sintering of Al4SiC4

A novel strategy for the fabrication of AlN–AlON refractories: Nitrogen gas pressure sintering of Al4O4C

“…Al 2 O 3 and AlN diffraction peaks appeared after thermal treatment at 1600 • C. The nitridation process is strongly dependent on atmosphere, pressures, temperature, and time. 5,15,16,28 Compare to the pressureless nitridation of Al 4 O 4 C, 28 the results indicate that GPS authentically promote the nitridation process. When the temperature rose to 1700 XPS was carried out to certify the combination of valence bonds of the specimen heated at 1700 • C. Figure 2A shows the specimen contained Al, O, C, and N elements after nitridation.…”

“…21,28 However, the high nitrogen pressure (20 atm) is essential for effective nitridation because faster diffusion of the nitrogen molecules could be achieved. 5 And the Al vapor generated in the matrix of Al 4 O 4 C specimen could react with N 2 before the dense nitride layers were completed. In addition, according to Fick's first law and classical collision theory, 44,45 the increase of nitrogen pressure in the constant volume of system can promote the diffusion flux and the diffusion rate of nitrogen.…”

“…[1][2][3] Meanwhile, their low strength and poor oxidation resistance inhibit a more wider application. [4][5][6] With the development of modern steel metallurgy technology, continuous deepening of energy saving, emission reduction, and manufacture efficiency improvement, the clean steel technology requires an extremely low carbon content in the steel. [7][8][9][10] Recently, the application of non-oxide composite refractories has been increasingly tapped into in high-temperature industry, among which AlN-AlON composites are considered to be a composite refractory owing to their excellent high temperature strength, thermal shock resistance, oxidation resistance, and good corrosion resistance to metallurgical slag and alkali.…”

“…For simplicity and efficiency, heat-treating singlephase ternary carbide is a promising and attractive method for composites because only one single raw material is required, with the homogeneous chemical composition. 5,[18][19][20][21] Al 4 O 4 C is a promising compound for high-temperature applications and refractory because of their high melting point (1890 • C), low density (2.684 g/cm 3 ), and excellent oxidation resistance. [21][22][23][24][25][26][27] The study on high-temperature behavior of pressed Al 4 O 4 C pellets under a nitrogen atmosphere indicated that a nitride layer generated on the surface and thereby slowed the nitrogen diffusion into the substrate.…”

“…In the nitridation process, the high nitrogen pressure is also favorable for the prevention of thermal decomposition of nitrides. 5,30 Meanwhile, the high pressure could accelerate the gaseous reactant diffusion into the matrix of dense specimens. For these reasons, a one-step N 2 GPS of Al 4 O 4 C was proposed in this work, and an innovation strategy for the fabrication of AlN-AlON refractories was developed.…”