Month: August 2018

How Does the Fused Zirconia Work in Modern Industry?

Zirconia and zirconite are the main raw materials of zirconia in nature. Pure zirconia is a white solid that will appear grey or light yellow when it contains impurities, and various other colors can be displayed by adding a developer. Pure zirconium oxide is a kind of advanced refractory raw material with a melting temperature of about 2900 ℃. Zirconia usually contains a small amount of hafnium oxide, which is difficult to separate but has no obvious effect on the properties of zirconia.

Zirconia has three crystalline forms: monoclinic, tetragonal and cubic. The zirconia at room temperature only appears in monoclinic phase, and it will be transformed into the tetragonal phase when heated to 1100 ℃ or so, and it will turn into a cubic phase when heated up to a higher temperature. Due to large volume changes when the monoclinic phase changes to the square phase, and large volume changes in the opposite direction when cooling, it is easy to cause product cracking, which limits the use of pure zirconia at high temperatures. However, the tetragonal phase can be stabilized at room temperature after adding stabilizer, so the volume mutation will not occur after heating, which greatly expands the application range of zirconia.

zirconite

Refractory materials and casting

There are two main refractory markets for the fused zirconia. The first is the cast steel refractories in the steel industry, particularly for the production of isostatic pressure molding products, which include intermediate flow slots and ladle outlets and immersion nozzles.

The second major market is the refractory produced by the electric melting and burning method in the special glass industry. Zirconia gives the molten glass good resistance to high temperature and corrosion. As there is no reaction area, there is no gravel in the glass. Aluminum-zirconium silicon refractories are graded by the content of zirconia, which is determined by the content of zirconia in the product.

Investment casting

For fused zirconia, investment casting is another major specialized market. For example, zirconia is commonly used as a model coating for the casting of special products such as aerospace engines, turbine engines, and golf clubs. Zirconite is used in investment casting because it can form actual contact with hot metal alloy to protect the die from thermal shock.

Abrasive substance

The polishing tools used in the ceramic industry, such as grinding wheel pieces and non-metal blades used in stone cutting, are made into coarse abrasive particles by mixing zirconia and alumina according to a certain formula, and then made into a grinding wheel or coated on the surface of grinding tool after thermal processing. This method can be used to polish steel and metal alloys.

Advanced ceramics and special products

For stable zirconia, the roasting control board for electronic components is a major market. Stable zirconia is also used in oxygen sensors and fuel cell partitions because it has the ability to allow oxygen ions to move freely in the crystalline structure at high temperatures, and the high ionic conductivity makes it one of the most promising materials for electrical ceramics. Chemical-grade zirconia is often used in electric melting products, and other special product markets include vacuum pumps and high-value components, special tool parts and brake lining. Fully stable cubic phase yttrium stabilized zirconia is used in the jewelry industry as a cheap alternative to diamonds.

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

Rare Metals Indispensable to Modern Industries: Zirconium

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 carriers, nuclear submarine and civil power reactors, and the hull of the 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, and nickel zirconium alloy, zirconium tin alloy, and niobium zirconium alloy and so on.

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 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.

industrial-grade zirconium

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 a solid solution at a 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 that 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 reactors. 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.