On-X Life Technologies, Inc. (On-X LTI) was formerly
Medical Carbon Research Institute (MCRI).
On-X Carbon
On-X carbon differs from the carbon used in other valves in that it is not alloyed with silicon carbide. It is 100% pure carbon. The silicon alloying in other valves is a means of providing consistent wear resistance required by heart valves.

A processing breakthrough by the Bokros team in 1992, however, provides needed wear resistance without the silicon. In addition, this form of pure carbon is actually tougher and stronger than the alloyed carbons.
Because On-X carbon is less brittle, valve design options were broadened to include flow-friendly features like the near-natural length and inlet flare. The pure surfaces provide a smoother surface finish and greater biocompatibility than alloyed carbons.
In addition, patented process technologies allow very precise dimensional control of the carbon coating process. This eliminates the need for machine grinding in the critical leaflet pivot areas, leaving smoothly blended, highly polished contours that wash freely.