Alumina is very abundant in the earth’s crust, with an average content of 15.34% in rocks, which is the second largest oxide in nature after SiO2. Therefore, alumina tube are widely used in the industrial field because of their high cost-effectiveness. This article briefly introduces the preparation process of alumina ceramic tubes.
Choose a reasonable molding method
In dry molding, we will first think of cold isostatic pressing. The isostatic pressing method is to seal the alumina powder into an elastic mold, and then put the mold into a container of high-pressure gas or liquid. After sealing, the powder is pressed into a green body with a higher density by using the characteristics of equal three-dimensional force. The main molding method for producing high-pressure sodium lamp tubes is isostatic pressing.
To further improve the density of the molded body, people have developed high-pressure molding and ultra-high-pressure molding based on ordinary isostatic pressing. These two molding methods have been used to prepare ceramic green bodies with relatively high density.
Wet molding: it has developed rapidly in recent years because it can control the agglomeration and impurity content of particles in the green body, reduce green body defects, and form ceramic parts with complex shapes. For example, centrifugal grouting molding is to evenly disperse the powder in the liquid by adjusting the pH value and other means, and then high-speed centrifugation is used to make the particles settle to obtain the green body.
There is also gel direct molding that makes the powder preparation and molding process go hand in hand, as well as gel casting molding that completes the green body solidification by polymerization of organic monomers and infiltration solidification method that relies on chemical potential molding. These methods have been well applied in the synthesis of some nanomaterials.
Key step: sintering method
The sintering quality directly affects the microstructure and a series of mechanical properties of ceramics. However, it is difficult to suppress the growth of grains by traditional sintering methods, and excessive growth of grain size may hurt the performance of ceramics. Therefore, some special sintering methods must be used, such as pressureless sintering and pressure sintering. Pressureless sintering is divided into reaction sintering and atmosphere sintering, and pressure sintering is divided into hot pressing, hot isostatic pressing, ultra-high pressure sintering, etc.
Precious Processing
Alumina ceramics are precision machined using various machine tools such as flat grinders, circular grinders, lathes, polishers, CNC, lasers, etc. We can process ceramic products of various sizes, precision, and finish requirements.
Edgetech offers various alumina ceramic products such as rods, tubes, plates, custom complex parts, etc.