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

摘要

A novel strategy was exploited for the fabrication of AlN-AlON refractories via nitrogen gas pressure sintering of Al4O4C. The phase transformation and microstructure evolution during the reaction at 1600-1800 degrees C were thoroughly investigated. The results indicated that the high N-2 pressure was essential for the effective nitridation. The in situ generated AlN-AlON refractories had a homogeneous local chemical composition, and the (101) plane of AlN and the (222) lattice plane of Al5O6N were bonded at their grain boundary with no amorphous phase. The as-fabricated AlN-AlON refractories treated at 1700 degrees C by a 20 atm nitrogen pressure exhibited an optimum bending strength of 111.10 MPa, combining an apparent porosity of 20% with a low bulk density of 1.97 g/cm(3). The diffusion of the generated oxygen led to an increase in the apparent porosity and decrease in the bulk density at 1800 degrees C. Furthermore, the fabrication mechanism of AlN-AlON refractories under the nitrogen gas-pressure was discussed.

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