Discharge plasma sintering furnaceIt is a device that uses plasma energy generated by electromagnetic fields to heat and sinter materials. This device adopts high-frequency discharge technology to convert gas into plasma, generating high-energy electrons in the plasma, causing violent collisions on the surface and inside of the material, thereby achieving rapid heating and sintering. The discharge plasma sintering furnace is widely used in fields such as material processing, surface coating, and new material research and development. Its characteristics include fast heating speed, uniform temperature, low energy consumption, and low pollution.
Equipment preparation and parameter setting:
Mold and sample loading:
Use graphite molds (temperature resistance ≥ 1600 ℃) to ensure uniform powder filling and moderate density, avoiding uneven sintering caused by local accumulation.
The inner diameter of the mold needs to match the sample size, usually with a 5-10% shrinkage allowance reserved.
Process parameter setting:
Temperature: Set according to the melting point of the material (for example, metal materials have a melting point of 0.5-0.7 times, and ceramic materials can be lowered by 200-500 ℃).
Pressure: Usually 30-50MPa, higher pressure is required for hard materials such as boron carbide.
Current: Pulse current range is 5000-25000A, which needs to be adjusted according to the conductivity of the material.
Time: Hold for 1-7 minutes to avoid grain coarsening.
Sintering process control:
Heating stage:
Adopting a stepped heating method (such as ≤ 100 ℃/min below 600 ℃, and up to 500-1000 ℃/min in high temperature zones).
Pulse current rapidly heats up through Joule heating, while activating electromigration and electroplasticity effects.
Plasma and densification:
Pulse current generates local high temperatures (up to 10000 ℃) in the gaps between particles, promoting surface evaporation and atomic diffusion.
The synergistic effect of pressure and current accelerates the elimination of pores, resulting in a density of over 98%.
Cooling and demolding:
Program cooling (such as 5-10 ℃/min) to avoid sample cracking caused by thermal stress.
Cool to below 200 ℃ before opening the mold to prevent oxidation of the graphite mold.