Silicon Carbide:  Silicon carbide resists a wide range of chemicals. It is also the hardest of seal face materials, giving it excellent abrasion resistance. Silicon carbide's high thermal conductivity and low coefficient of friction are essential for the effective sealing of volatile liquids and high pressure services. Reaction-bonded silicon carbide performs best at the highest speeds and pressures, but can be corroded by caustics and hydrofluoric acid.  Self-sintered silicon carbide resists all chemicals, and has running characteristics almost as good as reaction-bonded silicon carbide.

Alumina Ceramic:  Alumina ceramic is inert in pure form and is used in chemical and water applications as a mating ring for carbon-graphite primary rings. Alumina is limited to moderate speeds and pressures. Alumina is susceptible to thermal shock, and is not recommended for services involving periods of dry running or for petroleum refinery services.

Tungsten Carbide:  Tungsten carbide is a popular mating ring for carbon-graphite primary rings in hydrocarbon process applications and rugged applications involving vibration and mechanical shock. Tungsten carbide is a good mating face for silicon carbide primary rings in severe abrasive services, but is not as resistant to corrosion as silicon carbide.