What are the characteristics of special ceramics
From the perspective of raw materials, special ceramics have broken through the boundaries of traditional ceramics that use clay as the main raw material, and generally use oxides, nitrides, silicides, borides, and carbides as the main raw materials. Adding specially formulated inorganic materials to the ceramic body, after sintering at a high temperature of about 1360 degrees, obtains stable and reliable antistatic properties, and becomes a new type of special ceramics, which usually have the properties of electricity, magnetism, light, heat, sound, chemistry, One or more functions such as biology. As well as coupled functions such as piezoelectric, pyroelectric, electro-optic, acousto-optic, magneto-optical and others. For example, the treated ceramic fruit knife has a higher density than ordinary ceramic products, is environmentally friendly, does not rust, and does not oxidize.
Manufacturers of special ceramics believe that taking structural ceramics as an example, they are divided into four series: zirconia, alumina, silicon nitride, and silicon carbide. Zirconia ceramics are mainly used in civilian fields, such as ceramic knives, watches, and mobile phone backplanes in daily life. Alumina ceramics are mainly used in the fields of medical equipment and food. These fields have very strict requirements on the performance indicators of materials such as density, hardness, and toughness, so the materials are generally high-purity alumina. Ordinary alumina is generally used for less demanding products due to its low purity. In addition, with the continuous development of alumina ceramic technology, its application range is becoming wider and wider, and it has unique advantages in hardness and corrosion resistance, which will be the key development direction of the industry in the future.
Manufacturers of special ceramics believe that silicon nitride is a special ceramic developed and applied earlier in my country. It has the advantages of good thermal shock resistance, high hardness, wear resistance, and good bending resistance. It is mainly used in cutting tools, high-pressure plungers, heating plates and other fields. The main advantage of silicon carbide ceramics is corrosion resistance, which is mainly used in the chemical industry.
The technological process of special ceramics is roughly divided into five parts: raw material screening, molding, sintering, post-processing, and product testing. The selection of raw materials is very strict. It can be said that without good materials, the subsequent process is basically futile. Therefore, the choice of raw materials is an extremely important link to widen the product gap.
Secondly, on the basis of high-quality raw materials, there must be good technology and sintering equipment. From the "furnace" used for sintering, it can be divided into room temperature furnace, hydrogen furnace, GPS furnace, hot-press furnace, oxygen furnace and so on. The effect and color of different furnaces are uneven, how long will it take to process? We should pay great attention to the details of various process parameters, such as the time to apply pressure. In addition, finishing, as the essence of experiencing the added value of products, is also a step that requires a lot of energy after the product is sintered.
In terms of technology, the chemical composition, particle size distribution and particle morphology of special ceramic raw materials need to be strictly controlled, and precise stoichiometric ratios and new preparation processes need to be adopted to achieve some special performance requirements. Therefore, the entire process and process have a great influence on the effect of a product.