LockedBreech is correct. The Melonite (Burlington Engineering) process is practically identical to the Tennifer process. Both of them infuse nitrogen into the outer layers of the steel (nitriding) to make it harder and more resistant to wear and oxidation. The treatment goes much deeper into the metal than traditional bluing.
The Melonite process should not be confused with Melonite the mineral. There is no Tellurium involved in the steel treating process.