Translucent polycrystalline alumina ceramic tube,also known as translucent Alumina (semi-transparent alumina ceramics) or transparent polycrystalline alumina ceramics (transparent polycrystalline alumina ceramics); made of high purity AL2O3 (99.99%) and small amount of additives, e.g. pure magnesium oxide, lanthanum oxide and yttrium oxide; formed through continuous hot isostatic pressing (HIP), Presintering and sintering with regular crystal structure and good alkali-resistance to metal corrosion under high temperature; widely used in high-pressure sodium(HPC) lamp,     microwave integrated circuits, bearing, wear-resistant surface and infrared optical elements etc.