In many cases, zirconia ceramic raw material powder needs to undergo certain processing before use, such as calcination, crushing, classification, purification, etc. The purpose of processing zirconia ceramic raw materials is to adjust and improve the physical and chemical properties of zirconia ceramics so that the zirconia ceramics can meet the needs of subsequent processes and product performance. So what are the specific ones? Mingrui Ceramics will introduce it to you below.
1. Mixing of zirconia ceramic raw materials
In the preparation of special ceramics, two or more raw materials often need to be used, which requires mixing. Sometimes, although zirconia ceramic is a raw material, some trace amounts of additives need to be added and mixed. The quality of mixing directly affects the performance of the product. Especially when the density and ingredient ratio of the materials to be mixed are very different, or the properties of the materials are very special, it increases the difficulty of mixing.
2. Zirconia ceramic plasticization
The so-called plasticization refers to the process of adding plasticizers to zirconia ceramic materials to make the materials plastic. Plasticizer is only added when pressing difficult-to-press materials. In powder metallurgy, plasticizers are often called binders, and mixed with lubricants are called forming agents.
3. Zirconia ceramic granulation
In order to obtain good sintering performance and improve the final performance of the product, zirconia ceramics often need to use extremely fine raw material powder. However, the finer the powder, the poorer the fluidity, which is not only unfavorable for automatic pressing, but also the powder cannot evenly fill every corner of the mold. At the same time, the powder is fine, the bulk density is small, and the molding volume is large. For this reason, granulation is often required before forming.
4. Calcination of zirconia ceramic raw materials
The main purpose of generally calcining zirconia ceramic raw materials is:
a) Remove volatile impurities, chemically combined and physically adsorbed moisture gases, organic matter, etc. in the raw materials of zirconia ceramics, thereby improving the purity of the raw materials;
b) Densify the zirconia ceramic raw material particles and grow the crystals, which can reduce the shrinkage of zirconia ceramics during subsequent sintering and improve the quality of zirconia ceramic products. Pass rate;
c) Complete the crystal form transformation of zirconia ceramic allomorphs to form a stable crystal phase.
