High-temperature sintering furnaces adopt a double-shell structure and a 30-segment PID temperature control system, using phase-shifting trigger and thyristor control. The furnace chamber is built with both soft and hard carbon fiber insulation materials, enabling rapid heating and cooling. The outer shell is fully sealed, while the furnace lid and door are sealed with high-temperature silicone O-rings; the furnace door is equipped with a water-cooling system.
This type of furnace has the advantages of compact size, uniform temperature field, low external surface temperature, fast heating and cooling rates, competitive cost, and energy efficiency. It is an ideal sintering solution for universities, research institutes, and industrial enterprises.
High-temperature vacuum sintering reduces contamination from harmful components in the atmosphere—such as moisture, oxygen, and nitrogen. For example, reducing the moisture content in electrolytic hydrogen to a dew point of –40°C is difficult, but in vacuum sintering, as long as the pressure is maintained within a few hundred pascals, the vacuum condition is approximately equivalent to a –40°C dew point.
The evaporation loss of binder metals during vacuum liquid-phase sintering is a critical issue. This loss alters the final alloy composition and microstructure, and can also hinder the sintering process. Evaporation predominantly occurs in the final stage (the holding stage). The longer the holding time, the greater the evaporation loss. Chemical impurities, moisture, and other substances can react with carbon in the material to generate CO gas, which is discharged from the furnace, causing furnace pressure to rise and the total carbon content of the alloy to decrease.
The change in carbon content depends mainly on the oxygen content in the raw powder and the vacuum level during sintering. Higher oxygen and higher vacuum make CO formation more likely, increasing decarburization.
High-temperature sintering furnaces are mainly used for sintering reactive and refractory metals, hard alloys, magnetic materials, and stainless steel. In essence, they work under low-pressure (reduced-pressure) sintering conditions. The higher the vacuum, the closer the environment is to an inert atmosphere, reducing chemical reactions within the material. A high vacuum also promotes the removal of adsorbed gases and significantly improves shrinkage in the final sintering stage.