The purpose of sintering is to turn the powdered materials into the bulk materials, and providing the specific properties to the bulk material. It can be  divided into three stages when using the liquid-phase sintering method to prepare tungsten alloy counterweights: 1, the liquid phase generated and the particles rearrangement stage; 2, dissolution - precipitation stage; 3, the solid phase skeleton formation and grains growth stage. The density of the two-phase alloys, which sintered by liquid-phase sintering method is close to the theoretical density. This means that preparing tungsten alloy counterweights by liquid-phase sintering method may well keep their original high density characteristics, so that the tungsten alloy counterweights can exert great effectiveness and be better used in various fields.

 

1, The liquid phase generated and the particles rearrangement stage

 

This is the shortage stage which spent less time during tungsten alloy counterweight preparation process. At this stage, the nickel powders and iron powders will produce liquid phase as the temperature rises, and then produce the capillary force, which makes the powders to densify rapidly. Nickel is the essential element for the tungsten alloy counterweights preparation, the right amount of nickel (0.5% to 12%) can increase the viscosity between the powders and make it to a better densification. The degree of densification of the particles rearrangement stage depends on the liquid quantity, particle size, solubility of the solid in the liquid, etc., the compacts can be fully dense if the liquid number is sufficient(35%).

 

2, Dissolution - precipitation stage

 

The densification rate would be decreasded after the grains rearrangement stage, the dissolution and diffusion effect became the leader at this stage. The small powder particles would take precedence to be dissolved in the liquid phase, and the small particles precipitated on the surface of large particles with the particles size by diffusing and producing migrated substances, so that the particles can be coarsened and grew, while allowing the material to be further densified.

 

3, The solid phase skeleton formation and grains growth stage

 

The particles would be generated after liquid phase generated and the particles rearrangement stage and dissolution - precipitation stage, while producing the solid phase sintering on the particles contact surface and form a strong solid skeleton. But at this stage, it should not take too long time to sinter.

 

Tungsten alloy can achieve the fully dense between metals by liquid phase sintering preparation process, and then according to specific needs to create all kinds of different shapes counterweights, these counterweights have the excellent properties of high density, high thermal conductivity, corrosion resistance and anti-oxidation, etc., which makes it the best choice for many products in the field where needs counterweights.