Working theory：

By pre-pumping the furnace to vacuum and then heating to set temperature,inflate ammonia for nitriding process, then pumping and inflate again, after several cycles to reach aim nitride depth.

Advantages:

Compare with traditional gas nitriding. By the active of metal surface in vacuum heating, vacuum nitriding has better adsorption capacity, to realize less process time, higher hardness, precise control,less gas consumption,more dense white compound layer.