SiC powder has some curious uses in ceramic glazes. It is employed to make crater and foam glazes. The silicon takes up available oxygen to make SiO2 and the carbon combines with oxygen to make the CO2 that creates the blisters and bubbles. Using this mechanism it is possible to create reduction effects in oxidation firings, but with obvious challenges (blistering and bubbling). The carbon that silicon carbide particles release acts to reduce metallic oxides like iron and copper. Additions of tin oxide will aid color development, especially for copper reds. Fast firing is required as the SiC is rapidly depleted. The Potters Dictionary has a good description of this.