How to choose the best configuration for vacuum sintering furnace

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Vacuum sintering refers to the heating of powder, powder compact or other forms of materials under vacuum environment at appropriate temperature, and the connection between particles is achieved by atomic migration. The purpose of sintering is to make the porous powder compact have an alloy with certain structure and performance.

Advantages of vacuum sintering

1.Vacuum sintering can reduce the pollution of harmful components in the atmosphere (water, oxygen, nitrogen and other impurities, etc.) to the material, and avoid a series of reactions such as decarburization, carburization, reduction, oxidation and nitriding. The vacuum environment is not available in other sintering forms (when the vacuum degree in the furnace reaches 1.3*10-1 Pascal, the remaining gas in the furnace is equivalent to argon with a purity of 99.99987%).

2.Vacuum sintering can completely eliminate the particle oxide film before the liquid phase appears, thereby improving the wettability of the liquid phase with the carbide phase, improving the alloy structure, and improving the alloy performance.

3.Due to the reduction of the amount of gas in the pores of the compact under vacuum, the gas products are easier to discharge from the pores and the removal of the gas dissolved in the metal, making the material more compact.

4.Vacuum sintering can make the material more wear-resistant and strong.

5.Vacuum sintering also has a significant effect on reducing product costs.

Purpose and classification of vacuum sintering furnaces

Vacuum sintering furnaces are mainly used for sintering of powder metallurgy products, metal injection molding products, stainless steel bases, cemented carbides, superalloys, high-density gold, ceramic materials, magnetic materials, neodymium iron boron, etc.

There are two main types of vacuum furnaces: the first is divided into ordinary sintering furnaces (1300℃ and below), medium-temperature sintering furnaces (1300℃~1600℃), and high-temperature sintering furnaces (1600℃~2400℃) based on temperature. The second is divided according to the degree of vacuum, which can be divided into low vacuum, high vacuum and ultra-high vacuum sintering furnaces.

How to choose a vacuum sintering furnace

When using a vacuum furnace for work, the main purpose is heating. During the heating process, the heating rate is required to be fast. The selected heating material must ensure good thermal conductivity and cannot produce deformation and a large amount of heat loss at high temperatures. During use, it is also necessary to ensure that the performance is stable over a period of time. When selecting heating elements, it is also necessary to consider the chemical properties of the products to be processed, so as to avoid the material of the heating element affecting the quality of the workpiece. Therefore, it is necessary to select heating elements reasonably.

The heat shield is the main component of the vacuum furnace heating chamber. Its main function is to insulate, keep warm and reduce heat loss. It is also the structural basis for fixing the heater. Therefore, the choice of heat shield structure and material has a great influence on the power and performance (such as vacuum degree, degassing rate, etc.) of the vacuum furnace.

The heat shield is basically divided into two categories: metal heat shield and non-metal heat shield. The selection of heat shield is mainly determined by the sintering temperature, the physical and chemical properties of the product and the vacuum degree requirements. Compared with heat insulation elements made of other materials, elements produced with tungsten and molybdenum materials have better heat protection and can more effectively block heat convection.

Vacuum Sintering Furnace

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