Magnesia partly stabilized zircite floamed ceramic filter

Abstract

The invention belongs to a ceramic foam filter used in the casting industry. The invention proposes a technique which employs an organic solvent as a dispersing medium, a polymer material being capable of being dissolved into the organic solvent as a caking agent, and magnesia and monoclinic phase zirconia as the main materials to prepare a magnesia partially-stable zirconia ceramic foam filter. Absolute ethyl alcohol is preferably selected as the organic solvent for the consideration of environment protection. But the organic solvent covered by the invention also comprises the organic solvents capable of dissolving macromolecular caking agent like methanol, acetone, cyclohexanone, isobutyl alcohol, benzene, toluene, and the like. PVB is mainly selected as the macromolecular caking agent. The invention has the advantages of quick drying speed of a foamed ceramics biscuit, and saving the production time; moreover, the ceramic grains are piled compactly in the biscuit; the sintered foamed ceramic has uniform clearance and high high-temperature intensity, thus being capable of completely meeting the filtering on molten steel and high temperature alloy fused masses.

Description

technical field [0001] The invention belongs to a foam ceramic filter used in the foundry industry, in particular to a magnesia partially stabilized zirconia foam ceramic filter for filtering and purifying molten steel and superalloy melt with excellent thermal shock resistance and high temperature strength. Background technique [0002] In the production of castings, the use of foam ceramic filter metal liquid filtration technology, through three filtration and purification mechanisms of mechanical interception, rectification scum and deep adsorption, can effectively reduce or eliminate non-metallic inclusions and purify liquid alloys, thereby improving the quality of alloys. Improve the yield, improve the internal quality, working performance and machining performance of castings. [0003] For alloys with lower smelting temperature, such as copper, aluminum and magnesium, because the high temperature performance of the filter material is not high, ceramic foam filters made...

AI Technical Summary

Problems solved by technology

However, the preparation technology of zirconia-based foam ceramics has the following two difficulties: first, during the firing process of zirconia products, due to the martensitic phase transformation and the particularity of the foam ceramic structure, the blanking method is to use ceramic The slurry is formed by coating and hanging on the three-dimensional network foam plastic, and the bulk density of the powder is low. Compared with the pressure-formed zirconia ceramics, the sintering mass transfer process and solid solution reaction have other characteristics, and the sintering shrinkage is larger, so the part is stable. It is very difficult to develop zirconia foam ceramics, and foreign countries have always strictly adhered to technical barriers in this regard; second, when magnesia is partially stabilized, zirconia powder is easily hydrated to form magnesium hydroxide ( MgO+H 2 O=Mg(OH) 2 ), so the rheological properties of the prepared water-based slurry are poor, even if the solid content of magnesium oxide is low, it is difficult to have the characteristics of shear thinning, so that the ceramic slurry is not evenly adsorbed on the surface of the foam skeleton, and sintered In the process, magnesium hydroxide must first be decomposed into magnesium oxide, and then sintered with zirconium oxide, so the final product has low strength and is easy to crack