Chemically tempered glass
Chemically tempered glass is to improve the strength of the glass by changing the chemical composition of the surface of the glass. Generally, the ion exchange method is used for tempering. The method is to immerse the silicate glass containing alkali metal ions in the molten lithium (Li+) salt to exchange the Na+ or K+ ions on the surface of the glass with Li+ ions, and a Li+ ion exchange layer is formed on the surface. The coefficient of expansion is smaller than Na+ and K+ ions, so that the outer layer shrinks less and the inner layer shrinks more during the cooling process. When cooled to room temperature, the glass is also in a state of tension on the inner layer and pressure on the outer layer. Similar to physical tempered glass