Development of a high-density silicon carbide material for heating elements using a planning method

Conclusions

• 1. Using an experiment-planning method, a qualitative and quantitative study was made, in a total of only 12 experiments, of the effects of four processing factors upon the apparent density of monolithic polycrystalline silicon carbide. A satisfactory mathematicostatistical model of the manufacturing process was obtained, with the aid of which the range of optimum values of the optimization parameter and the corresponding values of the variables (factors) were determined by the successive approximations method.

• 2. Parts of the required qualify (an apparent density of 3.02±0.18 g/cm³ and a free silicon content of < 2.5%) can be obtained at the following values of processing factors: hydrostatic pressing pressure 450 kg/cm², petroleum coke content 31%, bakelite content 10%, silicon carbide No. 10 content 60%, and M14 silicon carbide content 9%.

• 3. The good agreement found between experimental and calculated values of AD is evidence that the model can be successfully employed for determining the optimization parameter.

• 4. Tests carried out at 1600°C on experimental heating elements made by the optimum process have shown that the material developed is suitable for high-temperature heating elements.