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Ceramic Foam Material

Ceramic Foam Material

Ceramic foam material is a new type of inorganic non-metallic filter material, ceramic foam material mainly uses raw ore powder, kaolin, or ceramic industrial waste slag, fly ash, coal gangue, marble tailings, slag, and other inorganic materials as raw materials, and a certain proportion of foaming agent, cosolvent, etc. are made into a water-based ceramic slurry, which is immersed on foam plastic to form a ceramic film coating, and then fired. According to the liquid metal objects to be filtered, common materials include silicon carbide, alumina, zirconia, and magnesia.

The pore size ranges from nanometers to micrometers, with a three-dimensional network structure and high porosity material characteristics, and the porosity can reach more than 90%. It has the advantages of lightweight, high porosity, large specific surface area, thermal shock resistance, corrosion resistance, high-temperature resistance, long service life, and good filter adsorption.

At present, ceramic foam has been widely used in many fields. In addition to purifying the metallurgical industry to filter molten metal, it is also used in applications such as heat and sound insulation materials and chemical catalyst carriers.

Ceramic Foam Material

Foam ceramic filters are mainly used in the casting process to purify liquid casting alloys and reduce or eliminate various non-metallic inclusions and exhaust problems during castings. Casting waste caused by casting defects such as non-metallic inclusions accounts for as high as 50%-60% of the total number of waste products. While various costs increase, the damage to the external environment caused by the outflow of excess waste can be predicted, and the inclusion defects are not only It seriously drags down the mechanical properties and casting performance of the castings, and also has a harmful effect on the cutting processing and appearance of the castings.

In order to solve this problem, people initially used wire mesh, steel plate with holes, etc., made simple filters inserted into the gating system to remove inclusions; to silicate pin fibers, boron nitride fibers and other two-dimensional structure inner filters. Nowadays, ceramic foam filters use pore size to mechanically intercept large particles of mixed oxides, and use filter cake to filter small particles of mixed oxides. And with adsorption and rectification capacity, the production line of foam ceramic filter is used, and the yield of castings has been significantly improved. For example, after the use of ceramic foam filters in Dongfeng Motor Foundry No. 2 Plant, the production rate increased from 65.3% to 71.5%, saving 6% of molten iron from the weight of the pouring riser. The hardness of the filtered castings is also significantly improved, thereby extending the service life of the cutting tool.

Foam ceramic filters generally use polyurethane foam as a carrier, immersed in a ceramic slurry made of fine powders such as refractory aggregate sintering aids, binders, and water, and then squeeze out the excess slurry, leaving the coating The ceramic material around the foam fiber is dried and fired and sintered at a high temperature to finally leave a foamed ceramic product. Due to the different pouring temperature of the casting alloy, the foam ceramic filter of refractory material should be selected for the casting. In recent decades, according to the performance of different material alloys, ceramic foam filters of various materials have been developed at home and abroad.

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