Lead-Free Low-Melting and Semiconductive Vanadate Glass Applicable to Low-Temperature Sealing

We optimized the fundamental composition and additives in a semiconducting V 2 O 5 –P 2 O 5 –TeO 2 glass system to develop lead-free low-melting glass suitable for low-temperature sealing below 400 °C. Glass with a composition of 55.7V 2 O 5 –19.8P 2 O 5 –23.5TeO 2 (mol %) has a low glass transformation temperature ( T g < 300 °C) as well as hard crystallization, and it is desired as a low-temperature sealing material. The effects of adding BaO, Sb 2 O 3 , MnO 2 , or Fe 2 O 3 to the fundamental composition of 55.7V 2 O 5 –19.8P 2 O 5 –23.5TeO 2 (mol %) on the thermal properties and water-vapor resistance were then characterized. Adding 11.7 mol % Fe 2 O 3 improved the water-vapor resistance drastically and decreased the thermal expansion coefficient without increasing T g . Sealing at 360 °C with our lead-free Fe 2 O 3 -added vanadate glass enabled practical airtight packaging on an electronic device.