The Microstructure Design of the Bonding System and Novel Technical Routes for Si3N4-Bonded SiC-Refractories

Nan Li, Yaowu Wei, Bingqiang Han, Junfeng Chen

The Key State Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081/China

Revision 15.05.2017, 17.10.2017

Volume 10, Issue 1, Pages 91 - 100

Abstract

In the present work, an overview of Si3N4-bonded SiC-refractories, including an optimised bonded system and simplifed production process, is given. The so-called Si3N4/SiC-bonded SiC-refractories were fabricated via introducing carbon sources into the matrix, with the reaction of carbon and free-Si during nitridation. The results indicated that the optimal nitridation degree and bonded morphology in matrix were achieved in the sample by adding carbon black. They both led to the further improvement in the properties of the fnal products. Furthermore, from a commercial perspective, there was a considerable impetus to develop low cost methods and simplify the existing tech-nology. So the second objective was to establish a simplifed sintering condition and suitable sintering additives for fabricating self-reaction bonded SiC-refractories. Here the alternative sintering atmosphere (in graphite bed) in combination with ferrosilicon was employed. This work was a meaningful attempt with an interesting result. The optimization in the processing and formulation was developed under controlling costs. So it has a potential application and feasibility in the refractory industry.

Keywords

Si3N4-bonded SiC-refractories, microstructure design, heat-treatment atmosphere, microstructure properties

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