US Patent 7556700 Ice skate blade produced by pulse plasma nitriding

A process to manufacture ice skate blades and the ice skate blades that result from this process where the blades of made from a nitridable steel hardened to a medium hardness (Rockwell C 38-55) then nitrides by a plasma nitriding process disclosed which prevents hardness loss in the steel while adding very hard nitride layer of a thickness in excess of 50 microns that gradually drops to the base steel hardness. The plasma nitriding process control is enhances dy addition of an intert gas and by the pulsing of the plasma field on and off for millisecond periods to prevent overheating of the ice skate blade during processing.