What is Zirconia Toughened Alumina? The zirconia toughened alumina (ZTA). is composed of zirconia & alumina. Because zirconia, an oxide of Zircon, is durable and often used in other materials. Zirconia toughened Alumina generally has a zirconia proportion between 1/10 to 1/5. You can adjust the ratio to fit the specific product. ZTA ceramics provide…