Titanium alloys are alloys that contain a mixture of titanium and other chemical elements. The callipers are aluminium alloy bodied with titanium pistons. Typical catalysts are sulfated oxides of titanium and zirconium or specially treated alumina or zeolites. These include iron, uranium, aluminium, nickel, platinum, tungsten, titanium, and copper. Such metals are beryllium, chromium, magnesium, titanium, and some aluminium alloys. These may include zirconium, tungsten, titanium, and barium. These can also include small amounts of boron, magnesium, aluminum, silicon, titanium, manganese, and iron. Other significant metallic alloys are those of aluminium, titanium, copper and magnesium. It is based on a nickel titanium shape memory alloy core. Dental implants are anchors placed in bone, usually made from titanium or titanium alloy. Other exotic frame materials include titanium and advanced alloys. Examples are carbon, iron, nitrogen (see nitrogen oxide), silicon, titanium, and aluminium. The pan is made of titanium or aluminum. Ilmenite is an oxide of iron and titanium. The airframe is constructed of titanium and high-strength aluminium alloys.