Zirconium oxide foam ceramic filter

Abstract

The present invention relates to a zirconium oxide foamed ceramic filter. It is made up by adopting the following steps: using zirconium oxide, aluminium oxide, calcium oxide and yttrium oxide to form ceramic powder, adding methyl cellulose, polyvinyl alcohol and water to prepare slurry, using soft polyurethane foamed plastics as carrier, impregnating said carrier with said slurry, extruding to obtain blank material, drying and sintering so as to obtain the invented zirconium oxide foamed ceramic filter. The invented foamed ceramic filter has good high-temperature stability and thermal shocking resistance in the high-temperature molten steel, does not contaminate alloy and can obtain good filtering purification effect.

Description

technical field [0001] The invention relates to the purification of molten metal, in particular to a foam ceramic filter. More specifically, the present invention relates to a ceramic foam filter containing zirconia as a ceramic component, and the filter prepared by the present invention is used for filtering and purifying metal melts such as cast steel and superalloy. Background technique [0002] During the smelting and pouring process of various metal liquid alloys, the casting reject rate caused by casting defects such as non-metallic inclusions and shrinkage holes is generally as high as 50-60% of the total rejects. Inclusion defects not only seriously reduce the mechanical properties and casting properties of castings, but also have harmful effects on the machining and appearance of castings. Purifying liquid casting alloys, reducing or eliminating various non-metallic inclusions and exhaust gases are undoubtedly important technical measures to obtain high-quality cas...

AI Technical Summary

Problems solved by technology

However, all these filters can only filter out large inclusions and very few small inclusions in molten metal through mechanical sieving

Due to the low refractoriness and strength of the aluminum silicate fiber filter, it can only be used for filtering non-ferrous alloys, cast iron and small steel castings, and it is difficult to withstand the impact of high-temperature metal fluid for a long time; the molybdenum wire and Although the boron nitride fibrous filter screen developed in the United States can be used to filter high-temperature alloys such as cast steel, its application is limited because of its high price.

There are also straight-hole core-type ceramic filters and refractory particle filters used for casting alloy filtration, but their porosity is small, and the filtration efficiency of the former is still low, and the filtration effect is unstable. Bonding effect makes it easy to leak particles and inconvenient to use

Although the sintered porous ceramic filter first successfully developed in the United States in the early 1970s solved the problems of easy particle leakage and inconvenient use of the refractory particle filter, it is different from the honeycomb straight-hole ceramic filter successfully developed in the early 1980s in the United States. Like the container, the porosity is still small, generally less than 50%, so that the flow rate of the molten metal is low

[0014] Although the research on the above-mentioned foamed ceramic filters has achieved certain results, they all have the disadvantages of high temperature resistance and poor impact resistance, and there are still defects when filtering a large amount of molten steel.