1. status quo of isostatic graphite produced by foreign enterprises
Russia, Poland: two countries isostatic graphite development level, the development time of about 20 years later, due to the lack of investment, the quality of products, far falls in the USA and Germany, behind France and Japan and other countries Chinese, is still in the stage of development and perfection.
Japan: Japan attaches great importance to the development of isostatic graphite.
At present, the Japanese isostatic graphite in the yield, quality, variety, specifications and development should have reached the advanced level in the world, mainly in: in isostatic graphite developed up to the enterprise, the products most varieties, specifications, the most widely: Japan isostatic graphite is not only used in semiconductor, solar energy, metallurgy, mechanical processing, atomic energy industry, but also applied to biological engineering and motor manufacturing etc..
2. status quo of isostatic graphite production in domestic enterprises
The development of isostatic graphite (isotropic graphite) in China. At the beginning of 60s, our country began to study the isostatic pressing technology, and carried out the trial production of various kinds of carbon, graphite and other kinds of powder. According to preliminary statistics, at present, domestic companies involved in the development and production of isostatic graphite are about 9 enterprises capable of producing independently
3. domestic and foreign isostatic graphite industry gap
Looking at the quality of products at home and abroad, especially the user feedback information, we realized that compared with foreign manufacturers, we still have a big gap, mainly in the following aspects: (1) the mechanical strength of products needs to be improved Carbon graphite products are brittle materials, but their mechanical strength is restricted, but it is an important index. The use of this unit has more stringent requirements, and compared with foreign products, there is indeed a big gap. Improving the volume density of products is one of the effective measures to improve the mechanical strength, but it has the limit. In order to improve mechanical performance, comprehensive measures should be taken. The content of ash (impurity) in carbon graphite products is an important technical index, and each product has a definite requirement. This is especially true for isostatic graphite. Because it is mostly used in high temperature or vacuum conditions, in order to prevent ash pollution of the surrounding environment and products, the ash content is often more stringent requirements. Under special conditions, not only the ash content is required, but also the components in ash are required. Many properties of carbon graphite materials are related to the degree of graphitization. The higher the graphitization degree, the better the conductivity and thermal conductivity, the higher the thermal stability, oxidation resistance, corrosion resistance and lubricity. The degree of graphitization is closely related to the ash content and is generally determined by the highest temperature of graphitization. That is to say, under the same process conditions, the higher the graphitization temperature, the lower the ash content and the higher graphitization degree. The application scope and isostatic graphite more widely, the use conditions are different, the graphite material requirements, will therefore not have focused on a variety of the world, maintaining the status quo, development of varieties is a pressing matter of the moment. The carbon graphite material under vacuum or protective medium, can work stably, the highest up to 3000 DEG C. But in reality, there are many occasions, requiring it to work in the air, high temperature conditions, such as continuous casting graphite, purification aluminum electrode. We know that the biggest defect of carbon graphite material is high temperature oxidation. In order to improve service life, One is to improve the oxidation resistance of carbon matrix, The second is to prevent oxidation, such as surface coating, plasma spraying, chemical vapor deposition, solid phase impregnation, etc.. Carbon graphite material under high temperature use conditions, undergo high temperature changes and not destroyed by the performance, known as thermal shock resistance, or referred to as thermal stability. Carbon graphite is a better material, but it also has some limitations. (4) product specifications need to be improved As mentioned earlier, with the rapid development of science and technology, the size of equal pressure static graphite also requires large scale development. The cylinder diameter of isostatic pressing machine by a few years ago with the diameter of 850 mm in recent years to the development of home purchase cylinder with the diameter of 1250 mm (maximum 2150 mm) isostatic pressing machine, the manufacturing of diameter 1000mm and larger specifications may become isostatic graphite. Products to large specifications, in addition to hardware (such as static press, baking furnace, etc.), the biggest bottleneck is the manufacturing process, to prevent product cracking is the key to baking, worthy of in-depth study of peers.
