Purity assurance and impurity control in the preparation process of zirconia ceramics
Publish Time: 2025-02-19
Zirconia ceramics, with its excellent physical and chemical properties, such as high hardness, high wear resistance, good biocompatibility, etc., have been widely used in many fields such as medicine, electronics, and chemical industry. However, the realization of these properties is inseparable from the strict control of purity and the effective reduction of impurity content in the ceramic preparation process.
In the preparation process of zirconia ceramics, the selection of raw materials is crucial. High-quality zirconium oxide raw materials are the basis for ensuring the purity of ceramics. Usually, the raw materials contain some impurities, such as iron, silicon, aluminum, etc., which will affect the performance of ceramics. Therefore, when selecting raw materials, zirconium oxide raw materials with low impurity content should be selected as much as possible, or effective purification methods such as chlorination and thermal decomposition, alkali metal oxidation decomposition, lime melting, etc. should be used to remove impurities in the raw materials.
In addition to raw material selection, pretreatment of ceramic powder is also an important link to improve purity. The pretreatment process may include steps such as cleaning, pre-burning, mixed plasticization, and granulation of the powder. Among them, the cleaning step is particularly critical, which can directly remove impurities on the surface of the powder. For example, for possible iron impurities, the pickling method can be used to inject a certain concentration of hydrochloric acid solution into the raw material, heat and boil it to dissolve the iron impurities in the acid, and then wash it with water several times to completely remove the iron impurities.
During the molding and sintering process, the conditions also need to be strictly controlled to avoid the introduction of new impurities. For example, during slip injection molding, the gypsum mold should be kept clean to prevent impurities in the gypsum mold from entering the ceramic body. During the sintering process, parameters such as sintering temperature, insulation time and sintering atmosphere should be accurately controlled to avoid the introduction of impurities or the decline of ceramic performance due to improper sintering conditions.
In addition, the use of additives is also an important factor affecting the purity of ceramics. In some cases, some additives need to be added to improve the performance of ceramics. However, the introduction of additives may also bring impurities. Therefore, when selecting additives, additives with low impurity content and little effect on ceramic performance should be selected as much as possible, and the amount of additives should be strictly controlled.
In summary, the preparation process of zirconia ceramics is a complex and delicate process, which requires strict control of multiple links such as raw material selection, powder pretreatment, molding and sintering conditions, and the use of additives to ensure the purity of the ceramics and reduce the impurity content. Only in this way can zirconia ceramics products with excellent performance be produced to meet the application needs of various fields.
