Controlled atmosphere furnace is sintered by a discharge plasma, which is a material state of a substance excited by high temperature or characteristic, and is a fourth state of a substance other than a solid state, a liquid state, and a gaseous state.

A plasma is an ionized gas, a quasi-neutral gas composed of a large number of positive and negative charged particles and neutral particles, and exhibits collective behavior.

Spark plasma sintering is a kind of powder metallurgy sintering technology to produce high performance materials by loading metal and ceramic powder into the mold, applying special sintering power and pressing pressure to sintering powder by upper and lower die punching and electrified electrode, through discharge activation, thermoplastic deformation and cooling.