Why Enamel Slurry Need To Be Aged?
Enamel manufacturers usually put the ground enamel slurry in a container and store it for a period of time before applying enamel. This process is called the aging of the enamel slurry. Different enamel slurry have different aging requirements, and the aging time of each enamel production factory is also different. The reasons for the aging of the enamel slurry are mainly as follows:
1. During the ball milling process, the temperature of the enamel slurry will increase, resulting in serious puffing. During the aging process, the puffing phenomenon will return to normal as the temperature decreases, which is convenient for enameling;
2. During the ball milling process, a large amount of air will be mixed in the enamel slurry. If the enamel is directly coated, it may cause the problem of air bubbles on the surface of the porcelain layer, and the aging can discharge excess gas;
3. When the enamel slurry just comes out of the grinding process, the hydrolysis of the enamel is accelerated due to tumbling, friction and other reasons, and the soluble alkali is precipitated to increase the pH value of the enamel slurry (especially for titanium enamel), thus affecting the luster of the enamel surface. Through aging, the enamel slurry will have a certain sedimentation phenomenon, and the surface layer solution can be removed to reduce free substances, which is beneficial to improve the quality of the enamel surface;
4. Soluble salts will also be released during the grinding process of the color enamel. If these soluble salts are not removed, the porcelain surface will show uneven color after firing (or after decoration). After aging, skim off the upper layer solution, which is beneficial to improve the quality of the colored enamel surface.
Under normal circumstances, ordinary ground coat enamel and edge enamel do not need to be aged, and can be used directly after grinding; titanium enamel is aged for 1~2 days, and antimony enamel is aged for about 5~7 days. The storage time of the enamel slurry should not be too long, otherwise particles will precipitate and the enamel slurry will be layered.