Synthesis of Nitride-Based Ceramics

The benefits of CS are fully exploited in the direct production of ceramic materials 

it may be concluded that for some ceramics, such as BN-based materials, CS is the technology, which allows to effectively produce materials that caimot be obtained by traditional methods. 

The following strategy for the CS of ceramic materials in gas-sohd systems was 

1) Green samples or net shape articles should have the optimum initial porosity (0o)- On the one hand, 0q should be as small as possible, which makes it easy to produce pore-free material after combustion sintering. On the other hand, as shown above, Bq is one of the main parameters that defines the combustion regime and the degree of final conversion for example, too small Bq could make impossible to accomplish the steady-state combustion regime. 

2) Initial reaction mixture is an important factor, which mainly defines the degree of conversion ( ). Indeed, as it was mentioned above, by dilution of the boron by boron nitride (z) leads to the significant increase of //. Again, optimization is required because too high dilution results in low combustion temperature and thus hinders the sintering process. 

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Combustion Synthesis of Nitride-Based Ceramics 71 Table 2.2 Some properties of BN-based ceramics. 

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