Zirconium alloy is a non-ferrous alloy composed of adding other elements to zirconium as a matrix. The main alloying elements are tin, niobium, iron, etc. Zirconium alloy has good corrosion resistance, moderate mechanical properties, low atomic thermal neutron absorption cross section, good compatibility with nuclear fuel, and is mostly used as a core structural material for water-cooled nuclear reactors in high temperature and high pressure water and steam at 300~400 °C. In addition, zirconium has excellent corrosion resistance to a variety of acids, alkalis and salts, and has a strong affinity for oxygen, nitrogen and other gases, so zirconium alloys are also used in the manufacture of corrosion-resistant parts and pharmaceutical machinery parts, and are widely used as non-evapotranspiration degassing agents in the electric vacuum and light bulb industries.
There are two types of zirconium alloys produced on an industrial scale: zirconium-tin and zirconium-niobium. The alloy grades of the former are Zr-2 and Zr-4, and the typical representative of the latter is Zr-2.5Nb. In zirconium-tin alloys, the alloying elements tin, iron, chromium, and nickel can improve the strength, corrosion resistance, and thermal conductivity of the corrosion-resistant film, and reduce the sensitivity of the surface state to corrosion. Usually the Zr-2 alloy is used in boiling water reactors, and the Zr-4 alloy is used in pressurized water reactors. In zirconium-niobium alloys, the corrosion resistance of the alloy is best when the amount of niobium is added to reach the solution limit of the crystal structure of zirconium at the service temperature. Zirconium alloy has homogeneous heterocrystalline transformation, and the crystal structure is body-centered cubic at high temperature and close-packed hexagonal at low temperature. Zirconium alloys have good plasticity and can be made into pipes, plates, bars and wires by plastic processing, and their weldability is also good, which can be used for welding processing.
Zirconium has a small thermal neutron capture cross-section and outstanding nuclear properties, which is an indispensable material for the development of the atomic energy industry and can be used as a structural material for reactor cores. Zirconium powder is flammable in the air and can be used as a detonator and smokeless gunpowder. Zirconium can be used as an additive for deoxidation and desulfurization of high-quality steel, and is also a component of armor steel, cannon steel, stainless steel and heat-resistant steel. Zirconium is an important alloying element in magnesium alloys, which can improve the tensile strength and processing properties of magnesium alloys. Zirconium is also a metamorphic agent for aluminum-magnesium alloys, which can refine grains. Zirconia and zircon are the most valuable compounds in refractories. Zirconia is the main material of new ceramics and cannot be used as a heating material to resist high-temperature oxidation. Zirconia can be used as an additive for acid-resistant enamel and glass, which can significantly improve the elasticity, chemical stability and heat resistance of glass. Zircon has strong light reflection performance and good thermal stability, and can be used as a sunscreen in ceramics and glass. Zirconium can absorb a large amount of oxygen, hydrogen, ammonia and other gases when heated, and is an ideal getter agent, such as zirconium powder as a degassing agent in electron tubes, and zirconium wire zirconium sheets as gate supports, anode supports, etc.