Densification of a SiC-matrix by electrophoretic deposition and polymer infiltration and pyrolysis process

With the aim to improve the properties of the SiC-matrix in a SiCf/SiC composite for fusion applications, a new fabrication technique combining electrophoretic deposition (EPD) and polymer infiltration and pyrolysis (PIP) was introduced. By using EPD from a well-dispersed, aqueous suspension we were able to produce SiC green bodies with closely packed particles (>62%TD). This deposition was followed by vacuum infiltration of the green body with pre-ceramic polymer precursor and then pyrolysis and crystallization at 1600 °C. Due to the high initial packing density of the deposits, only a few polymer-infiltration and pyrolysis steps were needed to achieve a relatively high density of the material. The SiC samples fabricated by the combined EPD-PIP process reached the matrix density of ∼86.5% TD and average pore size of ∼90 nm after six consecutive PIP cycles, while high thermal conductivity values (>30 W/mK) were obtained already after one PIP cycle.