What are the common problems in the application of graphite rods in vacuum sintering furnaces?

The common problems in the application of graphite rods in vacuum sintering furnaces are mainly the following:

Uniformity of graphite rod: As the electric heating body of the vacuum sintering furnace, the uniformity of the graphite rod directly affects the temperature distribution in the furnace. If the uniformity of the graphite rod is not good, it will lead to uneven temperature distribution in the furnace and affect the quality of the sintered parts. Therefore, when selecting graphite rods, high-purity graphite rods with good uniformity should be selected.

Antioxidation of graphite rods: When the graphite rod is heated in the air, a layer of silicon dioxide film will form on the surface, which plays a role in protecting the graphite rod. However, if the graphite rod is used intermittently in the vacuum sintering furnace, the silicon dioxide film may be destroyed when it is reused, resulting in a decrease in the oxidation resistance of the graphite rod. Therefore, when the graphite rod is used intermittently, the temperature reliability in the vacuum sintering furnace should be ensured to protect the oxidation resistance of the graphite rod.

Thermal expansion coefficient of graphite rod: The thermal expansion coefficient of the graphite rod is related to its carbon content. The higher the carbon content of the graphite rod, the greater its thermal expansion coefficient. In a vacuum sintering furnace, the graphite rod will expand as the temperature rises. If the thermal expansion coefficient does not match, it will cause stress between the graphite rod and the furnace wall, affecting the service life of the graphite rod. Therefore, when selecting graphite rods, appropriate graphite rods should be selected according to the temperature range and process conditions of the vacuum sintering furnace.

In addition, the following points should be noted when using graphite rods in vacuum sintering furnaces:

The surface of the graphite rod should be smooth to reduce friction with the furnace wall.

The graphite rod should maintain an appropriate gap with the furnace wall to prevent the graphite rod from contacting the furnace wall and ablation.

The graphite rod should be checked regularly and replaced in time when damage is found.

By paying attention to the above points, the application problems of graphite rods in vacuum sintering furnaces can be effectively avoided, and the service life of graphite rods and the quality of sintered parts can be improved.

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