Alpha sintered silicon carbide


A grade of silicon carbide (ceramic) that contains no silica.

It is also called a self sintered silicon carbide (sometimes called direct sintered or pressure less sintered)

  • This material begins as a mixture of silicon carbide grains and a sintering aid that is pressed and subsequently sintered as its name implies. Unlike reaction bonded SiC there is no free silicon present. These direct sintered materials have no metal phase and are therefore more resistant to chemical attack.
  • There are two grain shapes available to the manufacturer. Alpha (hexagonal structure) and Beta (cubic structure). There does not appear to be any great difference in the chemical resistance, wear or friction of these two grain shapes.
  • Most process chemicals will not attack these self sintered materials.
  • In the following box you will find the names of some of the bigger manufacturers of self sintered silicon carbide:
General Electric
  • Sintered silicon carbide is impossible to shrink into a metal holder.
  • Self-sintered silicon carbide carries a slight price premium compared to the reaction bonded version.

Although the preferred seal face material, it often is too brittle for some seal face designs.

It is one of the most popular materials used in mechanical seal face design and is recommended in high temperature water or hot oil applications because of its excellent thermal conductivity.

Alpha sintered silicon carbide is usually a better choice than the reaction bonded grade of silicon carbide.

Reaction bonded silicon carbide can be attacked by high pH chemicals similar to the caustic cleaners we find in the chemical industry