Reasons for cooling, shaping, and cracking of zirconia ceramics

Reasons for cooling, shaping, and cracking of zirconia ceramics

1. Vacuum method for zirconia ceramics

The zirconia ceramic vacuum method adopts the method of vacuum pumping outside the pipe to make the outer surface of the pipe adsorb on the inner wall of the shaping sleeve and cool to determine the outer diameter size. This method is particularly suitable for the extrusion method of ultra-high molecular weight polyethylene zirconia ceramic structural components.

2. Zirconia ceramic internal pressure method

It is a method of using compressed air under pressure inside zirconia ceramic structural components, and adding a cooling and setting sleeve to the pipe, so that the outer surface of the pipe is attached to the setting sleeve and quickly cooled and hardened to determine the outer size. The pipe is evenly drawn out through a traction device.

3. Sizing of Zirconia Ceramic Setting Port (Ejection Method)

This method does not require a traction device and directly ejects zirconia ceramic structural components into shape. The characteristic of the ejection method head structure is that the straight part of the core mold is about 10-50mm longer than the mouth mold. The screw thrust pushes the pipe out of the head and directly pushes it into the cooling water tank. The outer surface of the pipe cools and hardens, and the inner surface is sleeved on the core rod and cannot shrink inward to form a shape.

Reasons for cracks in the protective layer of zirconia ceramics

1. Caused by excessive fineness modulus and high mud content of zirconia ceramic sand;

2. Due to uneven mixing of zirconia ceramic slurry, stress is generated due to inconsistent shrinkage, resulting in cracks in the protective layer;

3. The cement proportion in zirconia ceramic mortar is too high and the grade is too high, resulting in excessive and rapid shrinkage of the mortar in the early stage;

4. The water absorption rate of zirconia ceramic protective layer slurry is too high, causing cracks due to winter frost heave;

5. Due to the insufficient flexibility index and low elongation of zirconia ceramic adhesive, the deformation resistance of the surface layer adhesive is reduced.

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