Factors Affecting the Quality of Dry Pressing Forming of Zirconia Ceramics

Dry pressing forming of zirconia ceramics, also known as molding pressing, is a process in which the granulated powder is placed in a steel mold and pressed on a press to make a certain shape green body.

Dry pressing forming of zirconia ceramics, also known as molding pressing, is a process in which the granulated powder is placed in a steel mold and pressed on a press to make a certain shape green body.

The dry pressing forming method is commonly used in the production process of advanced ceramic solid materials. Dry pressing forming is characterized by low binder content and can be sintered directly without drying. it has many advantages, such as simple production process, high efficiency, shrinking green body, automatic production, and so on. It can be widely used in the production of round and flaky functional ceramics and electronic components.

During dry pressing, the dry pressing quality of zirconia ceramics is affected by many factors, so what are these factors? Let Mingrui ceramics will analyze it for you.

1. The finish and fit of the mold

The dry pressing forming of zirconia ceramics has high requirements for the quality of the die, first of all, the hardness of the die should meet certain requirements.

Because the particles of zirconia stabilized material are very fine and the fluidity is poor, the finish of the die is required to be very high. If the finish can not meet the requirements, the flow of the material will be affected during dry pressing, which leads to the emergence of delamination.

At the same time, if the mold is not well matched and the gap is large because the zirconia powder particles are fine, the powder will flow out from the mold gap during pressing, resulting in a small amount of powder around the mold, so that the four sides can not be compacted during pressure. as a result, there will be layering due to inconsistent pressure transmission, so there are higher requirements for the coordination of the mold.

2. Demoulding method and speed

When the zirconia ceramics are demoulded by dry pressing, tools are generally used to push the green body out of the mold cavity, and the demoulding speed should be uniform and slow, which will cause the green body to crack if not paid attention to.

The practice shows that the demoulding tool should be flat during demoulding, otherwise it will cause uneven force on the green body and cause cracking. In short, dry pressing forming is related to the above-mentioned factors, in order to form an ideal green body, all the above aspects should be well controlled.

3. Pressurization speed and holding time

Poor control of pressing speed and holding time in the dry pressing of zirconia ceramics will also lead to defects such as delamination of zirconia green bodies.

The falling speed of the die should be slower, if the pressure speed is too fast, the gas in the green body is not easy to be discharged, resulting in delamination, dense surface, and loose middle, as well as the existence of bubbles and so on. If the holding time is too short, the external force will be removed before the pressure is transmitted to the proper depth, so that the gas in the green body is not easy to discharge, so it is difficult to get a more ideal green body, which will lead to delamination and the existence of bubbles and other phenomena. At the same time, the holding time should be uniform, otherwise, it will cause uneven thickness of the product and lead to waste products.

In addition, the forming pressure and pressing method of zirconia ceramics also have a great influence on the dry pressing quality of zirconia ceramics, so we should also pay attention to it.