Effect of Microwave Heating on Increasing Strength of Soda-Lime Glass by KNO3-Calcined Kaolin Slurry Spray Coating Technique

Abstract

This research investigated the effect of microwave heating on increasing the strength of soda-lime glass using a KNO₃-calcined kaolin slurry spray coating technique. Glass samples were coated using a spray technique and subjected to 1200W microwave heating at 40-50% power for 10-20 minutes in an alumina chamber with silicon carbide susceptor, followed by electric furnace treatment at 470°C for 0-4 hours. The mechanical properties were evaluated through flexural strength testing and Vickers microhardness measurements. Light transmission was analyzed using UV-VIS spectrophotometry, and potassium ion diffusion was examined using SEM-EDS. Results showed that microwave heating at 40% power for 10 minutes followed by electric furnace treatment at 470°C for 4 hours yielded the highest mechanical properties, with flexural strength reaching 370.65 MPa. The light transmission remained at 89%, equivalent to untreated glass, while achieving a potassium ion diffusion depth of 16 µm.