Hardness And Wear of Enamel Frit
The hardness of enamel is usually expressed by Mohs hardness. The hardness of enamel is between 5 and 6. The value of ordinary glass is 6, which is slightly higher than that of enamel. The alkali and boron in the enamel composition will affect the hardness.
Abrasion test means that the surface of the test piece is ground by abrasives with a certain particle size, and the weight will decrease after a certain period of time. An abrasion testing machine can be used to place a 10cmx10cm flat plate on the test piece table at the upper end of the instrument, with a rubber pad under it, and fix it on the mold. There are 9 test pieces in total, 6 of which are put into the same test piece at the same time, and at least one standard test piece is put into it. Put 175g of steel balls with a diameter of 5/32 inches, 3g of high-alumina abrasives of No. 80, and 20cc of water into the mold. After the testing machine is connected to the power supply, the upper plate vibrates horizontally at a certain speed. After an appropriate test time, the test piece is taken out, washed, dried, and weighed to obtain the weight loss.
Using this test method to find the weight loss of various enamels when the test time is 15 minutes:
Heat-resistant enamel frit: 44.6mg
Acid-resistant enamel frit: 72.7mg
Titanium enamel frit: 51.9mg
Enamel flat glass: 60.4mg
The above-mentioned heat-resistant enamel frit refers to stainless steel enamel frit, the firing temperature can reach 970~1000℃, and it has good wear resistance. The firing temperature of titanium enamel frit is lower than that of acid-resistant frit and glass, but the wear resistance is better, probably because the titanium enamel frit contains a lot of titanium oxide crystals.