Basalt fibre reinforced SiOC-matrix composites: Manufacturing technologies and characterisation

In order to evaluate the capability of resin transfer moulding for the manufacturing of fibre reinforced SiOC-composites derived from polysiloxanes, basalt fibre reinforced polysiloxane matrix composite plates were manufactured with uni-directional, orthotropic and quasi-isotropic lay-up. After precursor injection, the composites were thermally cured in the closed mould at temperatures below 200 °C. The cured polymer composites were pyrolysed in nitrogen atmosphere at 650 °C for 8 h and reinfiltrated with subsequent polymer infiltration and pyrolysis steps in order to reduce the matrix porosity. Characterisation of flexural strength was performed via three-point bending tests with pyrolysed samples. Especially the uni-directional composites show good mechanical properties comparable to samples manufactured via filament winding or pressing techniques. Additionally, hardness evaluation of matrix and basalt fibres was performed via Vickers micro hardness indentation for different pyrolysis temperatures in-between 600 and 1000 °C, showing a significant increase in hardness of the matrix in the temperature range above 850 °C.