Zirconium dioxide (ZrO₂) is the main oxide of zirconium. Under normal conditions, it is a white, odorless, and tasteless crystal. It is insoluble in water, hydrochloric acid, and dilute sulfuric acid. Zirconia ceramics are known for their excellent corrosion and abrasion resistance, high-temperature stability, fracture toughness, and strength. These properties make zirconia an ideal material for structural ceramic bearings, such as the 6205 UC205 model.