Originally Posted by seed
Tennifer uses cyanide as a medium and is either illegal to use in the U.S. or is strictly regulated (with obvious good reason). Melonite uses a different medium and is much more common here and is probably catching on in Europe.
Tenifer and Melonite are essentially the same process, both manufactured by HEF. Both develop a small amount of cyanide, along with the cyanates produced in the salt bath, which create a compound layer of nitride over a diffusion zone.