What Do You Know About Zirconium And Zirconium Alloys?

Compared with traditional iron, copper, nickel and other metal elements, zirconium has lower density and smaller thermal expansion coefficient. In addition, zirconium has a low thermal neutron absorption cross-section (only 0.18×10-28 m2) and good corrosion resistance, which makes zirconium and zirconium alloys have a wide range of applications in the nuclear industry, aerospace and other special fields.

Zirconium and its alloys have been widely used as cladding materials in nuclear reactors. Zirconium and its alloys reflect neutrons back into the reactor more efficiently than stainless steel, greatly saving uranium fuel; Zirconium alloy has good corrosion resistance in high temperature and high-pressure steam of 300 ~ 400 ℃, which also makes the reactor have a long service life. Therefore, zirconium is regarded as the first metal in the atomic age.

zr-alloy

Development status of zirconium and its alloys

Zirconium, which is found in the earth’s crust at about 220 g /t, ranks 20th, ahead of other common metals such as copper, nickel, lead, and cobalt. Initially, zirconium alloys were mainly used as cladding materials in the nuclear industry. In recent decades, zirconium alloys have been widely used in the chemical industry, medical industry, and some special fields.

Zirconium alloy for nuclear use

Zirconium alloys have been widely used in the nuclear industry because of their very low thermal neutron absorption cross-section and good resistance to high temperature and pressure corrosion. France, the United States, Germany, and Russia have developed a series of zirconium alloys for nuclear use. At present, Zr-2, Zr-4, Zr2.5nb and ZIRLO, E635, M5, and NDA zirconium alloys have been successfully applied in the nuclear industry. These newly developed zirconium alloys have lower radiation creep properties and better resistance to iodine stress corrosion. In addition, they are able to meet the requirements of high burnup of the fuel assemblies, increasing the service life of the assemblies to 30 years.

nuclear-reactor

Corrosion resistant zirconium alloy

Zirconium has excellent corrosion resistance against most organic acids, inorganic acids, strong alkalis, and some molten salts. Therefore, zirconium can be used to improve the service life of some key components in corrosive environments. Another way to improve the corrosion resistance of alloy parts is surface pretreatment. In industry, zirconium is placed in high-temperature air to obtain a dense oxide film, so as to improve the corrosion resistance and erosion resistance of zirconium and its alloys. The results show that the corrosion rate of zirconium treated by surface oxidation in sulfuric acid medium is only 5% of that of pure zirconium, but the erosion resistance is increased by twice.

At present, zirconium is widely used as corrosion resistant material in the chemical industry, and it has been widely used in the heat exchanger, dike washing tower, reactor, pump, valve, and corrosion medium pipeline. For example, zirconium alloys have been used to produce concentrated and hydrolyzed tubes in hydrogen peroxide production lines, while zirconium pressure reducing valves, agitators and flow meters are used in fertilizer production, sewage treatment, and dye industries.

Biomedical materials are a new high-tech material in recent years, and biomedical alloys must have good compatibility and corrosion resistance with the environment of biological fluids. Zirconium is valued by researchers for its good biocompatibility, elastic modulus similar to bone and corrosion resistance. Ti6Al4V, a titanium alloy implanted earlier in hard tissues of the human body, has an elastic modulus of nearly 110 GPa, which is much higher than the elastic modulus of 15 ~ 30 GPa of natural bones of the human body.

High strength zirconium alloy

In the fields of space exploration, deep-sea exploration, and high-speed railway, there are often some special operating environments, such as the alternating temperature environment of -200 ~ 200 ℃, continuous space irradiation and relative motion of structural parts, etc. Under these special circumstances, long-serving structural components are often faced with fatigue damage, dimensional instability, atomic oxygen erosion, and friction wear. At present, the structural parts used in these special fields are mainly made of 20Cr, GCr15 and other alloy steel materials, which often have problems such as poor radiation resistance, easy damage of moving parts, high density and high cost.

Compared with traditional alloy steels, zirconium and its alloys have several important potentials:

  • The thermal expansion coefficient of zirconium is small and the size structure is stable, so it has the potential to produce precise structural components;
  • It has the potential of resisting space radiation damage;
  • It has the potential to resist atomic oxygen erosion;

Therefore, zirconium and its alloys are expected to adapt to unconventional environmental conditions in special fields and have the potential to be used as structural components in special environments.

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Rare Metals Indispensable to Modern Industries: Zirconium

The zirconium has been regarded as a precious stone since ancient times due to its rich and colorful color, playing a decorative role in human life. As people’s understanding of zirconium deepens, the application of zirconium has penetrated into every aspect of our life. For example, all kinds of buildings, ceramics, knives, ornaments, etc., as well as the military and nuclear power fields are also featured with zirconium.

Zirconium is mainly used in ceramics and refractories in the form of zirconium silicate and zirconia. Only 3 to 4 percent of zirconium ore is processed into metallic zirconium, or sponge zirconium, which is further processed into various zirconium materials. Zirconium has excellent nuclear properties because of its small thermal neutron absorption section, and the nuclear grade zirconium is used as the structural material of nuclear power aircraft carrier, nuclear submarine and civil power reactor, and the hull of uranium fuel element. Another important use of zirconium metals is in the manufacture of alloys with excellent properties, such as aluminum zirconium alloy, copper zirconium alloy, iron zirconium alloy, nickel zirconium alloy, zirconium tin alloy, and niobium zirconium alloy and so on.

aluminum zirconium alloy

Currently, the most used materials in the industry are zircon, while a small number of zirconium compounds and metals. Zirconium ore and mineral powder are mainly used in refractory, casting, abrasive, ceramic and electronic industries. Zirconium compounds, mainly zirconia, are used in refractories, abrasives, electronic materials, glass additives, gemstones, sensitive materials and precision ceramics.

Zirconium metals can be classified into atomic and industrial grades by use. Atomic energy grade zirconium refers to the zirconium with a content of hafnium less than 0.01% in the metal, also known as hafnium zirconium or reactor grade zirconium, which is mainly used in nuclear reactors as nuclear fuel sheathing materials and core structural materials. In the chemical industry, smelting and other industries, zirconium does not need to be separated. Generally, zirconium-containing about 2.5% of hafnium is classified as industrial grade zirconium.

aluminum zirconium alloy

As an active metal, zirconium forms an oxide film at room temperature, which gives zirconium and its alloys excellent corrosion resistance. Moreover, zirconium also has good mechanical and heat transfer properties, as well as significant cost advantages, which makes it an excellent corrosion-resistant structural material in today’s petrochemical industry.

The zirconium applied in chemical acid-resistant equipment, military industry, and electronic industry is called industrial grade zirconium. In terms of processing difficulty and technological level, zirconium metal and its alloy products are at the top of the industrial chain.

Stanford Advanced Materials supplies high-quality zirconium products to meet our customers’ R&D and production needs. Please visit http://www.samaterials.com for more information.

What are the uses of Zirconium in the Vacuum Industry?

As a rare metal, zirconium is widely used in the fields of aerospace, military industry, nuclear reaction and atomic energy due to its remarkable corrosion resistance, extremely high melting point, ultra-high hardness, and strength.

The surface of zirconium is easy to form a glossy layer of the oxide film, so its appearance is similar to that of steel. Zirconium is resistant to corrosion but dissolves in hydrofluoric acid and aqua regia, and it can react with non-metallic elements and many metallic elements to form the solid solution at high temperature. Zirconium has good plasticity and is easy to be processed into zirconium plate and zirconium wire. Besides that, zirconium can absorb a lot of gases such as oxygen, hydrogen, and nitrogen when heated, and can be used as hydrogen storage material. Zirconium and hafnium are two metals with similar chemical properties, which are symbiotic and contain radioactive materials.

Zirconium Rod

The zirconium can absorb nitrogen violently when the temperature exceeds 900 degrees Celsius. At 200 degrees Celsius, 100 grams of metal zirconium can absorb 817 liters of hydrogen, equivalent to more than 800,000 times the hydrogen absorption capacity of iron. This characteristic of zirconium has been widely used. In the electric vacuum industry, for example, zirconium powder is coated on the surfaces of the anodes and other heated parts of the electric vacuum elements and instruments to absorb the residual gas in the vacuum tube, thus making the vacuum tube and other vacuum instruments, which have better quality and longer service life.

Zirconium can also be used as a “Vitamin” in the metallurgical industry, playing a powerful role in deoxygenation, nitrogen removal, and sulfur removal. For example, if a thousandth of zirconium is added to steel, its hardness and strength will increase dramatically. Zirconium-containing armor steel, stainless steel, and heat-resistant steel are important materials for the manufacture of defense weapons such as armored vehicles, tanks, artillery and bulletproof panels. When zirconium is mixed into copper and drawn into copper wire, its electrical conductivity does not weaken but the melting point is greatly improved, so it is very suitable to be used as a high-voltage wire. Zinc-magnesium alloys containing zirconium, which are light and high temperature resistant, are twice as strong as conventional magnesium alloys and can be used in the manufacture of jet engine components.

Zirconium alloy is a nonferrous alloy which is composed of zirconium as the matrix and other elements are added, and the main alloy elements are tin, niobium, iron and so on. Zirconium alloys have good corrosion resistance, moderate mechanical properties, low atomic thermal neutron absorption cross-section and good compatibility with nuclear fuel in the high-pressure water and steam of 300 ~ 400 ℃, which is mainly used as core structure material of water-cooled nuclear reactor. Besides that, zirconium has excellent corrosion resistance to a variety of acids, bases, and salts, and has a strong affinity with gases such as oxygen and nitrogen, and they are also used in the manufacture of corrosion-resistant and pharmaceutical mechanical components, as well as the non-evapotranspiration disinfectant in the electric vacuum and light bulb industries.

Stanford Advanced Materials supplies high-quality zirconium products to meet our customers’ R&D and production needs. Please visit http://www.samaterials.com for more information.