How to prevent glaze shrinkage from appearing?
There is a process of glazing in the production process of ceramic products. The so-called glazing refers to spraying a certain glaze slurry, that is, the glaze suspended in water, on the surface of the green body with compressed air. The green body quickly absorbs the moisture in the wet glaze and forms a certain hard surface, and a glaze layer with a thickness of 300 to 400 microns is formed on the surface of the fired product. However, many ceramic products have the phenomenon of shrinking glaze when they are released, that is, the glaze on the surface of ceramic products is missing in a large area. How to prevent the phenomenon of shrinking glaze in the process of ceramic production? The editor recommends that it is mainly in the control of the glazing process.
1. Before spraying the glaze, carefully clean the product to ensure that it is flat and clean;
2. Spray the green cloth with water before glazing, which helps to mix the residual dirt and soluble salts on the surface of the green body and place it on the glaze, but if the green body has been contained within 2 hours before glazing After scrubbing with a clean water sponge, no need to spray water;
3. Use clay with lower soluble salts to keep models and floors clean. When reused, remove BaC03;
4. Avoid getting oil or lubricating oil on the green body. In the process of cleaning the body before glaze spraying, the use of compressed air may bring in oil, so the compressed air should be filtered to remove oil;
5. Avoid touching or scraping the glaze layer after spraying the glaze;
6. The use of micron-scale fine raw materials can reduce the speed of the penetration of water on the glaze into the body. When the glaze is dried on the surface of the body, there is a large drying shrinkage, which is prone to cracks. Therefore, the amount of clay added to the glaze should not exceed 5%.