A kind of drying method of gel injection molding sic ceramic impeller wet blank

Abstract

The invention provides a drying method for gel injection molding SiC ceramic impeller wet blanks. Aiming at the problems that the ceramic impeller wet blanks are easy to crack and deform in the initial drying stage in the gel injection molding process, it is proposed to use polyethylene glycol The method of drying the wet impeller with the drying liquid and supporting the wet impeller with an inert hard tray. In this method, a high-concentration polyethylene glycol drying liquid is firstly configured, and then the wet impeller and the inert support tray are immersed in the drying liquid to complete the second stage. Dry in the first stage, and then put it into a constant temperature and constant humidity drying box to complete the second stage of drying. Adopting this method makes the drying environment milder, the green body is dried evenly and thoroughly, and defects such as cracking and deformation of the green body caused by gravity and drying stress are avoided. The method is simple in operation, low in cost, short in production cycle and high in efficiency, greatly reduces the difficulty of drying large-sized impellers, and prepares large-sized impellers with a diameter of more than 350 mm.

Description

technical field [0001] The invention belongs to the field of manufacturing ceramic impellers, and in particular relates to a drying method for a wet body of a SiC ceramic impeller formed by gel injection molding. Background technique [0002] Chemical, petroleum and nuclear power plants often need to pump in or out high-temperature, strong acid-alkaline solutions or corrosive liquid metals. Metal impellers are easily corroded, and there is an urgent need for a high-temperature, corrosion-resistant and wear-resistant impeller. ceramic impeller. SiC ceramics not only have excellent mechanical properties at room temperature, such as high bending strength, excellent oxidation resistance, good corrosion resistance, high wear resistance and low friction coefficient, but also high temperature mechanical properties (strength, creep resistance etc.) are the best known ceramic materials. The high temperature strength of hot pressing sintering, pressureless sintering and hot isostati...

AI Technical Summary

Problems solved by technology

However, the small molecular chains in the low molecular weight drying solution can easily penetrate into the SiC ceramic wet body during the liquid phase drying process, resulting in low drying effect and incomplete drying.

In addition, this patent (patent number CN101486579A) does not carry out corresponding support treatment on the complex shaped SiC ceramic wet blank, which may easily lead to defects such as deformation and cracking of the SiC impeller wet blank due to improper support during the drying process

In addition, the patent (Patent No. CN101486579A) directly dries the wet billet in the air after liquid phase drying without humidity control, which can easily cause cracking during the natural drying process; the Chinese patent (CN102887711A) also uses low molecular weight Ethanol and glycerol prepare the drying solution, and the ethanol molecules can easily penetrate into the porous structure of the SiC wet body during the liquid phase drying process, reducing the drying effect

In addition, this patent (CN102887711A) uses an overly soft plush carpet as a supporting medium, which can easily cause the impeller wet blank to crack during drying and shrinkage due to lack of strong support matching its complex shape; literature (doi:10.3390 / ma8074344 ) Although high-molecular-weight organic matter solutions such as polyethanol are used as desiccants, there is no support treatment for gel-casting wet blanks, and it cannot be used to dry large-size SiC ceramic impeller wet blanks with complex shapes

Therefore, there is currently no defect-free drying method for large-sized and complex-shaped SiC ceramic impeller wet blanks, and it is necessary to develop new drying processes and methods