Microwave Sintering of SiAlON Ceramics with TiN Addition.

Özgür Sevgi Canarslan,Alpagut Kara,Roberto Rosa,Paolo Veronesi,Erhan Ayas,Levent Köroğlu

doi:10.3390/ma12081345

Özgür Sevgi Canarslan, Alpagut Kara + Show 4 more

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https://doi.org/10.3390/ma12081345

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Abstract

α-β SiAlON/TiN composites with nominal composition of α:β = 25:75 were fabricated by microwave sintering. The effect of titanium nitride addition on the phases, microstructure, microwave absorption ability and mechanical properties (Vickers hardness and fracture toughness) of the SiAlON-based composites were studied. Finite Difference Time Domain (FDTD) software was used for the numerical simulation in order to assess the most suitable experimental setup. Sintering trials were performed in a single mode microwave furnace operating at 2.45 GHz and a power output of 660 W, for a reaction time of 30 min. SiC blocks were used as a susceptor to accelerate the microwave processing by hybrid heating, with reduced heat losses from the surface of the material of the α-β SiAlON/TiN composites. The optimum comprehensive mechanical properties, corresponding to a relative density of 96%, Vickers hardness of 12.98 ± 1.81 GPa and Vickers indentation fracture toughness of 5.52 ± 0.71 MPa.m1/2 were obtained at 850 °C when the content of TiN was 5 wt.%.

Highlights

SiAlONs are ceramics named after the elements they contain: silicon (Si), aluminium (Al), oxygen (O) and nitrogen (N)
SiAlON ceramics are widely used for a large range of structural and engineering applications such as gas turbines, heat insulators, cutting tools and spray nozzles and as refractories in the molten metal industry thanks to their excellent mechanical properties, such as high strength, high decomposition temperature, excellent thermal shock and good wear-resistance, low coefficient of friction and resistance to corrosive environments [1,2]
SiAlON-based ceramics typically exhibit one of two structures, the growth of which is dependent on their general chemical formula

Summary

Introduction

SiAlONs are ceramics named after the elements they contain: silicon (Si), aluminium (Al), oxygen (O) and nitrogen (N). SiAlON ceramics are widely used for a large range of structural and engineering applications such as gas turbines, heat insulators, cutting tools and spray nozzles and as refractories in the molten metal industry thanks to their excellent mechanical properties, such as high strength, high decomposition temperature, excellent thermal shock and good wear-resistance, low coefficient of friction and resistance to corrosive environments [1,2]. Such properties are closely linked to the microstructure, chemical composition and fabrication process. The first of these is α-SiAlON, which has a formula of

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