For those who have already learned about ceramics, whether during university or through special classes, there's probably no doubt about "what is glaze?" But for those who aren't yet proficient or haven't studied ceramics before, you might wonder: is glaze similar to taking your car to the service center to get a glass coating? Or is it similar to getting your nails done and then applying a coating to make them shiny? Today, SOC: SCHOOL OF CERAMICS , a school for teaching ceramics by POTTERY CLAY, has the answer.
The term "glaze " in ceramics refers to a thin layer of glass applied to the surface of a clay product. It is formed by melting a silicate mixture, not by other chemical compounds, but by combining several ingredients that form glass. Its purpose is to create a thin layer of glass that covers the surface of the clay or product. Therefore, one of the important components of a glaze that must be present is "glass."
The raw materials used in the glaze to create glass must contain silica ( SiO 2) as a key component. Examples of these raw materials include sand, quartz, quarry stone, rice husk ash, etc. But that's not all, because the composition of the glaze must include a "glass melting agent" or what is called Flux.
The melting point of glass is above 1300 °C , so it is necessary to add a substance to help the glass melt at a lower temperature. This substance is usually an alkaline substance consisting of Group 1 or Group 2 elements in the periodic table, such as ash , lime , dolomite , talcum , ZnO ( zinc oxide) , BaO ( barium oxide), etc.
There is also a "viscosity factor" that prevents the glass material from flowing out of the container and can stick to the surface of the container, such as alumina ( AL 2 O 3), which is obtained from soil , quarry stone, etc. in the glaze mixture.
* SOC : SCHOOL OF CERAMICS, a school teaching ceramics by POTTERY CLAY, offers glazing classes, with a total study period of 3 months. If interested, please contact us at LINE @SOC.TH.