Aluminum oxide short-fiber enhanced magnesium-oxide-based foam ceramic filter and preparation method thereof

Abstract

The invention discloses an aluminum oxide short-fiber enhanced magnesium-oxide-based foam ceramic filter with chemical stability and excellent thermal shock resistance capable of sintering in a low temperature and a preparation method thereof. The preparation method comprises the following steps: (1) according to a mass percent, compounding by 15%-25% of nano-aluminum sol, 0.8%-1.5% of rheologicalagent, and the balance of magnesia ceramics powder containing aluminum oxide short-fiber and nano-titania, adding absolute ethyl alcohol, ball-milling, and uniformly mixing to prepare ceramic slurryof which the solid content is 60%-70%; (2) immerging a polyurethane foamed plastic template in the ceramic slurry, extruding the polyurethane foamed plastic template through a roller press so as to remove redundant immerging slurry, preparing a biscuit, and removing an ethyl alcohol solvent in a ventilating chamber in 40-50 DEG C, and drying the biscuit; and (3) placing the dried biscuit in a sintering furnace, warming to 1350-1550 DEG C, and sintering in a high temperature, cooling to room temperature along with the furnace, to obtain the magnesium-oxide-based foam ceramic filter.

Description

technical field [0001] The invention relates to a magnesium oxide-based foam ceramic filter and a preparation method thereof, in particular to an alumina short fiber reinforced magnesium oxide-based foam ceramic filter and a preparation method thereof, belonging to the field of metal materials and metallurgy. The filter prepared by the invention is particularly suitable for filtering and purifying magnesium and its alloy melts, and can also be used for filtering and purifying aluminum and its alloy melts. Background technique [0002] Magnesium is chemically active. During casting and processing, it is very easy to chemically react with oxygen, nitrogen and water vapor. The resulting products remain in the magnesium, affecting the internal quality of the product and deteriorating the performance of the product. According to the types and properties of inclusions in magnesium alloys, inclusions are generally divided into two categories: metal inclusions and non-metal inclusio...

AI Technical Summary

Problems solved by technology

Chinese patent documents CN1011306B (pure magnesia foam ceramic filter and its preparation process), CN101138691A (preparation method of magnesia foam ceramic filter for casting), etc., prepare foam ceramics with pure magnesia as raw material, because MgO has a very high melting point and coefficient of thermal expansion (13.5×10 -6 /°C) is high, therefore, it leads to difficult sintering (sintering temperature is not lower than 0.8 times its melting point) and poor thermal shock resistance, which limits the application and development of MgO foam ceramics

add V 2 o 5 In powder form, MgO will react with V at 1190°C 2 o 5 form an approximate composition of Mg 3 V 2 o 8 The liquid phase promotes sintering and can significantly reduce the sintering temperature of MgO foam ceramics, but V 2 o 5 Harmful to the respiratory system and skin during use, and has strict restrictions on operation

with V 2 o 5 Similarly, cobalt oxide is also a good low-temperature sintering aid, but its application is limited as a highly toxic substance and rare resource

Fluoride is a strong co-solvent and mineralizer commonly used in ceramic industry sintering, Chinese patent documents CN100536986C (magnesia foam ceramic filter), CN1473947A (foam ceramic for magnesium and magnesium alloy melt purification), CN101785944B (for magnesium Fluorite (melting point 1423°C) and magnesium fluoride (melting point 1248°C) are added to the preparation method of magnesium oxide foam ceramic filter for magnesium melt filtration. The solid solution of fluoride not only increases the oxidation of the matrix during the sintering process The lattice of magnesium is distorted, and it is easy to form a low-melting liquid phase, thereby reducing the sintering temperature of magnesia ceramics; however, during the sintering process, F in fluoride combines with Si, Al, Fe, and Ca, and most (in ceramic tiles) About 70% in production) volatilization in gaseous form not only erodes the green body itself and damages the quality of sintered ceramics, but more seriously, it will cause fluoride pollution when discharged into the atmosphere. Fluoride can enter...

Images