Zirconium materials – Page 2

Zirconium 702 Alloys: Powering the Future of Nuclear Energy

In the realm of nuclear energy, the role of advanced materials is paramount in ensuring safety, efficiency, and sustainability. Among these materials, Zirconium 702 alloys have emerged as a cornerstone in nuclear applications, particularly in the construction of fuel cladding for reactor cores. Let’s delve into the exceptional properties and critical applications of Zirconium 702 in the nuclear industry.

Zirconium 702, a zirconium alloy primarily composed of zirconium with a small percentage of other elements, boasts a combination of properties that make it uniquely suited for nuclear environments. One of its defining features is its low thermal neutron capture cross-section, which minimizes the chances of neutron absorption and subsequent production of undesirable isotopes. This property is crucial in maintaining the stability and controllability of nuclear reactions within a reactor core.

Corrosion resistance is another standout attribute of Zirconium 702 alloys. In the harsh and chemically reactive environment of a nuclear reactor, where extreme temperatures and corrosive agents are prevalent, Zirconium 702’s ability to withstand corrosion ensures the longevity and safety of fuel cladding. This corrosion resistance is essential for preventing the release of radioactive materials into the reactor coolant.

Mechanical strength is a third key factor. Zirconium 702 alloys exhibit impressive mechanical properties, enabling them to withstand the mechanical stresses and pressures experienced during reactor operation. This strength is pivotal in maintaining the integrity of fuel rods and preventing breaches that could lead to fuel leakage.

Zirconium 702 alloys find extensive use in pressurized water reactors (PWRs) and boiling water reactors (BWRs), which represent the majority of commercial nuclear power plants globally. In PWRs, Zirconium 702 cladding encases the fuel pellets, providing a barrier that contains radioactive byproducts and prevents contact with coolant. In BWRs, Zirconium 702 components contribute to the stability and efficiency of the reactor core.

Advancements in Zirconium 702 alloy technology continue to enhance its performance in nuclear applications. Research focuses on optimizing the alloy’s microstructure, refining manufacturing processes, and exploring innovative coatings to further improve corrosion resistance and mechanical durability.

In conclusion, Zirconium 702 alloys have revolutionized the landscape of nuclear energy. Their low thermal neutron capture cross-section, corrosion resistance, and mechanical strength are pivotal in ensuring the safety and efficiency of nuclear reactors. As the world strives for cleaner and more sustainable energy sources, Zirconium 702 alloys remain at the forefront of powering the future of nuclear energy.

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Best Practices for Handling and Fabricating Zirconium Sheet

Zirconium sheet is a valuable material known for its exceptional corrosion resistance and heat transfer properties. However, working with zirconium requires careful handling and adherence to specific guidelines to ensure safety and maintain the material’s desirable properties. This article outlines best practices for handling, cutting, welding, and fabricating zirconium sheet, providing insights into proper storage, equipment selection, and safety precautions.

Further Reading: An Introduction to Zirconium Sheet: Properties and Applications

Storage and Handling

Proper storage of zirconium sheet is crucial to prevent contamination and damage. Store sheets in a clean, dry area away from direct sunlight, moisture, and corrosive substances. Use pallets or racks to prevent contact with the floor and keep sheets separated to avoid scratching or deformation. When handling zirconium sheets, wear gloves to prevent fingerprints, which can affect the material’s surface and subsequent fabrication processes.

Equipment Selection

When working with zirconium sheet, it’s important to use appropriate tools and equipment to prevent contamination and ensure precise fabrication. Select cutting tools, saw blades, and grinding wheels specifically designed for zirconium or other reactive metals. Avoid using carbon steel or iron-based tools that can contaminate the surface and compromise the corrosion resistance of the zirconium sheet.

Cutting and Machining

Zirconium sheet can be cut using shears, band saws, or abrasive waterjets. For precision cutting, using waterjets or laser cutting is recommended. When machining zirconium, ensure proper cooling with water-based lubricants to dissipate heat and prevent overheating. Maintain low cutting speeds to minimize heat generation and avoid work hardening, which can lead to cracking or reduced ductility.

Welding and Joining

Zirconium sheet can be successfully welded using various techniques such as TIG (Tungsten Inert Gas) welding or electron beam welding. Before welding, ensure the sheet and welding area are clean and free from contaminants. Use specialized zirconium welding filler rods with matching composition to maintain the material’s corrosion resistance. Strictly follow proper shielding gas techniques to prevent oxygen and nitrogen contamination during welding.

Safety Precautions

Working with zirconium sheet requires strict adherence to safety precautions due to its reactive nature. Wear appropriate personal protective equipment (PPE), including gloves, safety glasses, and protective clothing. Implement proper ventilation in the workspace to control dust and fumes. Avoid contact between zirconium and flammable materials, as it can ignite under certain conditions. In case of a fire involving zirconium, use dry powder or sand to extinguish it, as water can react explosively with zirconium at high temperatures.

Surface Finishing

Zirconium sheet surfaces can be enhanced through various finishing techniques like polishing, brushing, or electrochemical etching. However, it is essential to avoid contact with abrasive cleaning pads or brushes that can introduce contamination. Utilize specialized tools and cleaning agents specifically designed for zirconium to maintain its integrity and surface quality.

Quality Control

Implement stringent quality control measures throughout the handling and fabrication process to ensure the integrity of zirconium sheet. Conduct regular inspections to identify any signs of contamination, damage, or defects. Non-destructive testing methods such as dye penetrant testing or ultrasonic testing can be employed to detect surface cracks or flaws that may compromise the material’s performance.

Conclusion

Following best practices for handling and fabricating zirconium sheet is paramount to ensure safety and maintain its desirable properties. Proper storage, equipment selection, and adherence to safety precautions while cutting, welding, and finishing zirconium sheet are crucial. By following these guidelines, industries can maximize the benefits of zirconium sheet, including its exceptional corrosion resistance, heat transfer efficiency, and mechanical properties. Remember, when in doubt, consult with material suppliers or experts experienced in working with zirconium to ensure the highest standards of safety and quality.

For more information about zirconium sheets and other zirconium products, please visit https://www.samaterials.com/70-zirconium.html.

An Introduction to Zirconium Sheet: Properties and Applications

Introduction

Zirconium sheet is a versatile and highly sought-after material known for its exceptional properties and wide range of applications. With its remarkable corrosion resistance, excellent heat transfer capabilities, and inherent mechanical strength, zirconium sheet has become indispensable in numerous industries. In this article, we will delve into the properties of zirconium sheet and explore its various applications.

Exceptional Corrosion Resistance

One of the most impressive attributes of zirconium sheet is its outstanding corrosion resistance. Zirconium has a thin oxide layer that forms naturally on its surface, providing a protective barrier against aggressive chemicals, acids, and alkalis. This makes zirconium sheet particularly valuable in chemically demanding environments such as chemical processing plants, pharmaceutical manufacturing, and seawater desalination facilities. When exposed to corrosive substances, zirconium sheet remains unscathed, ensuring long-lasting performance and reliability.

Excellent Heat Transfer Capabilities

Another significant advantage of zirconium sheet lies in its excellent heat transfer capabilities. Zirconium exhibits high thermal conductivity, allowing efficient heat exchange between fluids or gases. This property makes zirconium sheet an ideal choice for heat exchangers in industries like petrochemicals, power generation, and refrigeration. By utilizing zirconium sheet in heat exchangers, manufacturers can enhance energy efficiency, reduce costs, and ensure optimal performance.

Mechanical Strength and Structural Integrity

In addition to its corrosion resistance and heat transfer properties, zirconium sheet possesses impressive mechanical strength and structural integrity. It has higher strength compared to other materials like stainless steel or aluminum, making it suitable for demanding applications. Zirconium sheet finds extensive use in aerospace industries, where its strength contributes to the manufacturing of lightweight but strong components. Moreover, this material is utilized in defense applications, providing the required durability to withstand extreme conditions in military equipment.

Nuclear Applications

Zirconium sheet has a vital role in nuclear applications, specifically in fuel cladding for nuclear reactors. The unique properties of zirconium make it an excellent choice for this purpose. It exhibits low neutron absorption, allowing neutrons to penetrate through the material without significant loss. Zirconium’s high melting point and exceptional corrosion resistance enable it to withstand the rigorous conditions within the reactor core, ensuring the safety and integrity of nuclear fuel rods.

Other Applications

The versatility of zirconium sheet extends beyond its primary uses. It is also employed in various other fields and industries. In the medical sector, zirconium sheet is gaining popularity for orthopedic and dental implants due to its biocompatibility and corrosion resistance. The electrical industry utilizes zirconium sheet in capacitors, connectors, and electrical contacts due to its advantageous electrical conductivity. Zirconium sheet is also used in the production of specialty chemicals, catalysts, and electrodes, benefitting from its chemical stability and catalytic properties.

Conclusion

Zirconium sheet stands as a remarkable material with its impressive properties and diverse range of applications. Its exceptional corrosion resistance, excellent heat transfer capabilities, and mechanical strength have made it essential in numerous industries. From chemically aggressive environments to nuclear power plants, from aerospace to medical applications, zirconium sheet continues to play a crucial role. With ongoing advancements in zirconium sheet technology and growing awareness of its benefits, we can expect this versatile material to find even more innovative applications in the future.

For more information about zirconium sheets and other zirconium products, please visit https://www.samaterials.com/70-zirconium.html.

The Versatile Metal: Zirconium’s Applications in the Chemical Industry

Zirconium is a versatile metal that is widely used in the chemical industry due to its excellent resistance to corrosion. In this article, we will explore some of the many applications of zirconium in the chemical industry.

Properties and Characteristics of Zirconium

Zirconium is a transition metal that is known for its high melting point, low thermal neutron cross-section, and exceptional corrosion resistance. Its atomic number is 40, and it has a silvery-gray color when in its pure form. Zirconium has several characteristics that make it well-suited for use in chemical processes, including:

Excellent corrosion resistance: Zirconium is highly resistant to corrosion, making it an ideal material for use in aggressive chemical environments.
Solubility: Zirconium is relatively insoluble in water and most common acids and bases, but can dissolve in hydrofluoric acid, which can be useful in certain chemical processes.
Oxidation resistance: Zirconium forms a protective oxide layer when exposed to air or water, which enhances its corrosion resistance.
Biocompatibility: Zirconium is biocompatible and is often used in medical implants and prosthetics.

Applications of Zirconium in the Chemical Industry

Zirconium has a wide range of applications in the chemical industry, including:

Manufacturing of pigments: Zirconium is used as a raw material to produce pigments such as zirconia and zirconium silicate, which are used in the manufacture of ceramics, glass, and tiles.
Corrosion-resistant equipment: Due to its exceptional corrosion resistance, zirconium is used in the manufacture of heat exchangers, reaction vessels, and other equipment that comes into contact with corrosive chemicals.
Catalysts: Zirconium-based catalysts are widely used in the production of various chemicals, including plastics, rubber, and pharmaceuticals.
Nuclear fuel cladding: Zirconium alloys are used as cladding materials for fuel rods in nuclear reactors due to their high strength, low thermal neutron cross-section, and excellent corrosion resistance.
Electronics: Zirconium compounds are used in the manufacture of capacitors, resistors, and other electronic components.

Safety Considerations

While zirconium is generally considered safe for use in the chemical industry, there are some safety considerations to keep in mind. These include:

Reactivity: Zirconium can react violently with certain chemicals, such as strong oxidizers like chlorine trifluoride or sodium chlorate. Workers should be trained on the safe handling of zirconium and its compounds.
Dust inhalation: Zirconium metal and some zirconium compounds can produce fine dust particles when processed or machined, which can be harmful if inhaled. Proper respiratory protection should be used when handling zirconium in powder form.
Radioactivity: Zirconium is not inherently radioactive, but it can become so if it is exposed to radiation in a nuclear reactor. Proper handling and disposal procedures must be followed for any zirconium-based materials that have become radioactive.

Conclusion

Zirconium is a versatile metal that has many important applications in the chemical industry due to its exceptional resistance to corrosion, ability to withstand high temperatures, and biocompatibility. Its use in manufacturing pigments, catalysts, corrosion-resistant equipment, nuclear fuel cladding, electronics, and more continues to make it an important material in modern industrial processes. As with any chemical, proper safety precautions must be taken when handling zirconium, but when used properly, it can contribute to safer, more efficient chemical processes.

For more information about zirconium metal or other materials, please visit https://www.samaterials.com/.

Exploring the Properties of Zirconium for Use in Nuclear Reactors

Zirconium is an important material used in the production of nuclear fuel rods for nuclear reactors. In this article, we will explore zirconium’s unique properties that make it an ideal choice for use in nuclear reactors, as well as some of the challenges and concerns associated with its use.

Physical and Chemical Properties of Zirconium Fuel Rods

Zirconium fuel rods are composed primarily of zirconium metal, which has several important physical and chemical properties that make it an ideal material for use in nuclear reactors. These include:

High melting point: Zirconium has a high melting point of 1855°C, which makes it able to withstand the extreme temperatures generated by nuclear fission reactions.
Low thermal neutron absorption: Zirconium has a low cross section for absorbing thermal neutrons, which are the neutrons that slow down as they collide with other atoms. This makes it an ideal material for use as cladding around fuel pellets, as it does not interfere with the nuclear reactions taking place inside the fuel pellets.
Excellent corrosion resistance: Zirconium is highly resistant to corrosion, particularly in high-temperature, high-pressure environments such as those found in nuclear reactors.
Good mechanical properties: Zirconium has good mechanical properties, including high strength, ductility, and toughness, which help to ensure the integrity and safety of the fuel rods.

Advantages of Using Zirconium as Nuclear Fuel

The use of zirconium as a nuclear fuel has several advantages, including:

High thermal conductivity: Zirconium has a high thermal conductivity, which helps to efficiently transfer heat away from the fuel pellets to the coolant in the reactor.
Low neutron absorption: As mentioned earlier, zirconium has a low cross section for absorbing thermal neutrons, which allows the neutrons to pass through the cladding and interact with the fuel pellets, resulting in sustained nuclear reactions.
Excellent corrosion resistance: Zirconium is highly resistant to corrosion, which is important in preventing the release of radioactive materials into the environment.
Readily available: Zirconium is abundant in the earth’s crust and is relatively easy to mine and process, making it an economically viable choice for use in nuclear reactors.

Disadvantages of Using Zirconium as Nuclear Fuel

However, there are also some disadvantages to using zirconium as nuclear fuel, including:

Potential for hydrogen buildup: When zirconium is exposed to water at high temperatures, it can react with the water to produce hydrogen gas, which can build up inside the fuel rods and potentially lead to explosions or other safety issues if not properly managed.
Radioactive waste: Like all materials used in nuclear reactors, zirconium fuel rods eventually become radioactive and must be properly disposed of once they are no longer usable. This can be a time-consuming and expensive process.
Regulatory concerns: The use of zirconium as nuclear fuel is subject to strict regulatory oversight to ensure the safety of workers, nearby communities, and the environment. Compliance with these regulations can be costly and time-consuming for nuclear power plant operators.

Safety Concerns and Regulations

Due to the potential hazards associated with the use of zirconium as nuclear fuel, there are several safety concerns and regulations in place to ensure the safe operation of nuclear reactors. These include:

Inspections and monitoring: Nuclear power plants are subject to regular inspections and monitoring by regulatory agencies to ensure compliance with safety standards.
Emergency preparedness plans: Nuclear power plants must have detailed emergency preparedness plans in place in case of an accident or other emergency situations.
Worker training and protection: Nuclear power plant workers must undergo extensive training on safety procedures and must be provided with appropriate protective gear and equipment when working with radioactive materials.

Conclusion

Zirconium is a unique and important material in the production of nuclear fuel rods. Its high melting point, low thermal neutron absorption, excellent corrosion resistance, and good mechanical properties make it an ideal choice for use in nuclear reactors. However, there are also some challenges and concerns associated with its use, including the potential for hydrogen buildup, radioactive waste, and regulatory compliance. As such, the use of zirconium as nuclear fuel is subject to strict safety regulations and oversight to ensure the safety of workers, nearby communities, and the environment.

For more information about zirconium or other metals, please visit https://www.samaterials.com/.

Application and Prospect Analysis of Zirconium

Zirconium is a metal material with superior physical and chemical characteristics. It is used in a variety of industrial, scientific, and technological applications. The following is an analysis of the uses and prospects of zirconium from different angles.

Zirconium Used in Nuclear Energy

Zirconium is one of the essential elements in the realm of nuclear energy due to its physical characteristics. Fuel rods and structural components for nuclear reactors can be manufactured with zirconium alloys. The high melting point, corrosion resistance, high strength, and high-temperature stability of zirconium alloys make them ideal materials for producing nuclear reactor fuel rods. Statistics show that every year, roughly 50 tons of zirconium alloys are used in the production of nuclear reactors worldwide.

Zirconium Used in Aerospace Industry

Zirconium is frequently utilized in the aerospace industry due to its superior mechanical qualities and strong temperature endurance. Zirconium alloys can be used to create components for aero engines such as blades, nozzles, and combustion chambers. Zirconium alloys can be utilized for a variety of components, including spacecraft hulls, turbines, and combustion chambers. They have exceptional qualities that can enhance spaceship performance, including lightweight, high strength, and high-temperature durability.

Zirconium Use in Medical Field

Zirconium is used extensively in the medical industry. Drugs can be radiolabeled using the zirconium isotope zirconium-89 for the detection and management of certain malignant disorders. Zirconium alloys have high strength, strong biocompatibility, and corrosion resistance, which can increase long-term durability and biological compatibility, and they can also be utilized to make artificial joints, dental implants, and other biomedical materials.

Zirconium Used in Chemical Industry

The chemical sector additionally employs extensive use of zirconium. Zirconium compounds are used in a variety of industries, including oxidants, antiseptics, catalyst supports, and catalysts. Because zirconium alloys offer great corrosion resistance, high-temperature stability, and long-term use in hostile chemical environments, they can also be utilized to make reactors, heat exchangers, reactors, and other equipment.

Zirconium Used in Electronics

Zirconium is also widely used in the field of electronics. Zirconium alloys and zirconates can both be used to create capacitors and battery electrodes, respectively. The primary areas of zirconium used in the electronics sector are nanotechnology and high-temperature superconducting materials. Zirconium can be used as an addition to boost the superconducting temperature and current density of high-temperature superconducting materials. Zirconium is also frequently utilized in nanotechnology and is capable of producing nanotubes, nanocrystals, and nanomaterials.

Zirconium Used in Metal Surface Coating

To stop corrosion and increase the hardness of metal surfaces, zirconium can be utilized in the production of surface coatings. Zirconium alloys can also be used to create metal coatings that are resistant to corrosion at high temperatures and have great corrosion resistance. Zirconium alloys are also perfect for producing drill bits, saw blades, and other tool materials due to their wear durability, and corrosion resistance.

Related reading: Where Zirconium is Used?

Conclusion

To sum up, zirconium has significant uses in the sectors of nuclear energy, aircraft, medical treatment, the chemical industry, electronics, and metal surface coating due to its exceptional physical and chemical qualities. The sustainable development of zirconium and the creation and use of ecologically friendly materials will also become popular trends as people’s awareness of environmental protection rises, further broadening the material’s potential uses.

Hydrogenation Method: A Method for Preparing Zirconium Powder

Introduction

Hydrogenation is one of the main methods for producing zirconium powder in the industry. This method refers to the process of preparing metal zirconium powder by hydrogenating and dehydrogenating bulk metal zirconium. The product metal zirconium powder prepared by the method has a purity of more than 98%, and can be mainly used in powder metallurgy additives and pyrotechnic industries.

Reaction Process

Zirconium has good plasticity and is difficult to be crushed by mechanical means, but it can be transformed into a brittle intermediate product zirconium hydride for further processing.

When hydrogen is sufficient, zirconium reacts with hydrogen to form zirconium hydride, releasing a lot of heat. The reaction formula is:

Zr+H2→ZrH2

When dehydrogenated by heating under a vacuum, zirconium hydride decomposes into metallic zirconium. The reaction formula is:

ZrH2→Zr+H2

Zirconium hydride is a non-stoichiometric substance in the interstitial phase, and the hydrogen content (x) can vary from zero to 2 with different process conditions. When x>1.65, it is brittle zirconium hydride, and the brittleness increases with the increase of x value. Zirconium powder can be obtained by grinding the brittle zirconium hydride finely and then dehydrogenating it in a high-temperature vacuum.

According to the requirements for product purity, the bulk zirconium raw materials used for hydrogenation include sponge zirconium, zirconium ingots, or zirconium scraps in zirconium processing; in order to ensure product quality, high-purity hydrogen must be used; the hydrogenation process should be in a well-airtight environment in a stainless steel reaction tank.

Specific steps are as follows:

After the reaction tank is filled, vacuum until the pressure is lower than 0.1Pa, heat to a temperature of 873-973K, and stop vacuuming.
Introduce high-purity hydrogen for hydrogenation. Sponge zirconium and zirconium shavings have a large specific surface area, which can be met by hydrogenation once. The dense zirconium with a large size needs to undergo multiple hydrogenation and dehydrogenation treatments at high temperatures to make it fully burst to ensure that the product is easy to grind. As long as the temperature and pressure of the hydrogenation process are well controlled, zirconium hydride with the desired hydrogen content can be obtained.
After the hydrogenation reaction is completed, continue to pass hydrogen to cool to room temperature, then extract the residual hydrogen, slowly fill in argon or air, and start unloading.
Put block zirconium hydride into a grinding tank, add the appropriate amount of water or ethanol to grind, then sieve and dry to get zirconium hydride powder. This zirconium hydride powder can be used as a heat-burning agent or powder metallurgy additive.
Spread the dried zirconium hydride powder into a thin layer in a tray, then put it into a dehydrogenation tank, and heat it slowly under a vacuum. Zirconium hydride releases a large amount of hydrogen at a temperature of about 673K.
When the temperature rises to 873-973K and the vacuum pressure reaches below 0.1Pa again, cool the dehydrogenation tank to room temperature, slowly pour water or ethanol into it, and then unload.
After grinding, sieving, and drying, the product zirconium powder is obtained.

Advantages

The zirconium powder produced by this method can maintain the content of metal impurities at the level of the raw material while ensuring that it is not contaminated by the container, and the content of some volatile impurities will be reduced, but the content of gas impurities, especially oxygen, will be reduced. Increase. The average particle size of zirconium powder can reach 5-10μm, and finer particle sizes can be separated through liquid countercurrent classification. The finer the particle size of the zirconium powder, the higher the oxygen content.

Attention

Zirconium powder, zirconium hydride powder, and hydrogen are flammable and explosive substances, and fine zirconium powder can oxidize, spontaneously ignite or explode even at room temperature. Explosion-proof measures should be taken during the production, storage, transportation, and use of zirconium powder to ensure safety.

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4 Methods for Making Metal Zirconium

Zirconium and its alloys not only have good machinability, moderate mechanical strength, and high corrosion resistance, but also have a low neutron cross-section. In the nuclear energy industry, they are widely used as structural materials for water reactors. Zirconium widely exists in zircon, so most methods of preparing metal Zr use zircon as a raw material for extracting zircon. This article will mainly introduce four methods for purifying zirconium.

Metal Thermal Reduction Method

The reducing agents used in the thermal reduction method are mainly calcium and magnesium.

(1) Calcithermic reduction

Using ZrO2 as raw material and calcium as a reducing agent, the reduction reaction is carried out at 1273-1373K under vacuum. The reduction product is a powdery mixture of Zr, CaCl2, CaO, and Ca, which can be pickled, washed with water, filtered, dried, and sieved to obtain metal zirconium.

(2) Magnesium reduction method

The magnesium reduction method mainly includes steps such as the preparation of zirconium tetrachloride, purification, magnesium reduction, and vacuum distillation. Chloride zirconium dioxide or zircon sand to obtain zirconium tetrachloride, purify, remove impurities such as SiCl4, TiCl4, AlCl3, FeCl3, and then use molten magnesium to reduce ZrCl4 to obtain a mixture of metal zirconium, magnesium, and magnesium chloride, and finally, Zirconium metal is obtained by distillation and purification.

Hydrodehydrogenation

This method uses the reversible absorption characteristics of zirconium to hydrogen to prepare zirconium powder. At a certain temperature, zirconium and zirconium alloys absorb hydrogen to form hydrides or solid solutions. When reaching a certain level, the material will produce microcracks, become brittle, and contain a lot of hydrogen. Such powder is called zirconium hydride powder. Zirconium hydride powder is dehydrogenated under high temperature and vacuum conditions to obtain zirconium powder. After years of improvement and promotion, this method has become the main method for producing zirconium powder.

Molten Salt Electrolysis

Metals or alloys that are difficult to electrodeposit in an aqueous solution usually use molten salt electrodeposition. Insoluble anodes are usually used, stainless steel or other refractory metals are used as cathodes, and molten salts of electrodeposited metals and alkali metal chlorides or fluorides are used as electrolytes. During the electrolytic reduction process, they are decomposed by the electrolytic metal molten salts. and deposited at the cathode.

Direct Electro-Deoxidation Method

The direct electro-deoxidation method uses a single or mixed metal oxide as the raw material, presses it into a block as the cathode, removes the oxygen in the cathode by electrolytic deoxidation, and obtains a metal element or alloy with low impurity content in a high-temperature molten salt, also known as FFC Law. The metals successfully prepared by the FFC method include Zr, Hf, Be, Mg, Ca, Ba, V, Nb, W, Fe, and Cu.

Among the four methods, the magnesium reduction method and hydrogenation-dehydrogenation method are the main production methods in the industry.

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The Importance of Surface Coatings for Zirconium Alloy Cladding

Safety Issues in The Application of Zirconium Alloys

In the past few decades, zirconium alloy cladding has been successfully applied to light water reactors (LWR), and has shown good radiation resistance and corrosion resistance. However, a major problem in the application of zirconium alloys in stacks is that they react violently with water vapor at high temperatures, and when the temperature is greater than 1200 °C, a large amount of hydrogen and heat will be released. After the Fukushima nuclear power accident in Japan, the safety of nuclear power has once again been placed in front of all nuclear workers. How to further improve the safety and reliability of light water reactor nuclear fuel elements under accident conditions has become an urgent problem to be solved. Research and development directions include accident-resistant fuel cores and accident-resistant cladding materials.

Cladding Material for Zirconium

The accident-resistant cladding material has good thermodynamic properties, which can improve the reaction kinetics of zirconium and water vapor and reduce the hydrogen release rate. The development of this material is mainly reflected in two aspects: one is to improve the high-temperature oxidation resistance and strength of the zirconium alloy cladding; the other is to develop non-zirconium alloys with high strength and oxidation resistance. This paper discusses the research on the surface coating of zirconium alloy cladding for the former.

The main advantage of the application of coated zirconium cladding is economical. The technical challenge it faces is to meet various performance requirements of the fuel cladding and components without changing the size of the fuel cladding. During long-term operation, the coating should have certain stability under corrosion, creep, and abrasion conditions.

Research Status of Zirconium Alloy Cladding Surface Coating

The anti-oxidation coating technology on the surface of zirconium alloy is the main method to improve the anti-oxidation ability of the surface of zirconium cladding. The outer surface of the zirconium alloy is coated with a layer of material to enhance the wear resistance and high-temperature oxidation resistance of the cladding, thereby improving the accident resistance of the zirconium cladding under normal working conditions and accident conditions. At present, some preliminary screening results have been obtained in international research on the surface coating of zirconium alloy cladding, and the coating materials mainly involve MAX phase and metal Cr.

MAX-phase coating

A series of studies have shown that:

The essence of the MAX phase coating is the dressing effect, and the key to the problem is to solve the diffusion of oxygen atoms to the zirconium substrate.
No matter whether in a fast neutron reactor or thermal neutron reactor, under the three activation time conditions, the activity of MAX phase material is similar to that of SiC, but three orders of magnitude lower than that of 617 alloys.
The thickness of the MAX phase coating should be controlled at 10~30 μm to limit the loss of neutrons.
Ti3SiC2 shows better prospects than Ti2AlC as a candidate material for MAX-phase coatings for high-temperature nuclear energy applications.
At room temperature, the radiation resistance of Ti3AlC2 is better than that of Ti3SiC2, and the radiation stability of the two MAX phase materials at 600 ℃ is better than that at room temperature.

Metal Cr Coating

A series of studies have shown that:

The high-temperature oxidation resistance of the coated zirconium alloy is obviously better than that of the Zr-4 substrate.
The high-temperature oxidation resistance of the coated zirconium alloy is significantly stronger than that of the zirconium alloy substrate, and the Cr-coated zirconium cladding has better ductility.
The metal Cr coating has good high-temperature oxidation resistance and can be used as a candidate coating material for accident-resistant zirconium alloy cladding.

For more information about zirconium materials, please visit https://www.samaterials.com/70-zirconium.html.

If you are interested in coating materials, you can find more information at https://www.sputtertargets.net/.

3 Manufacturing Methods of Zirconium-containing Refractories

What is Zirconium-containing Refractory Material?

Zirconium-containing refractory materials are made of zirconia (ZrO2) and zircon (ZrSiO4) as raw materials. “Zirconium-containing” usually refers to materials containing the following zirconium products: zirconia, zircon, zirconium mullite and zirconium corundum. Zirconium-containing products have good corrosion resistance to various molten metals, acidic reagents and liquid glass.

Zirconium-containing refractory materials can be divided into the sintered, fused cast, and non-fired products based on different manufacturing methods.

What are the Different Manufacturing Methods?

Sintered Zr-Containing Refractory Product

The basic steps to manufacture zirconium-containing sintered bricks are to prepare raw materials, press green bodies, and sinter at high temperatures.

Another method is to obtain blanks by granulation, kneading, machine pressing or extrusion molding, and the clinker fired at high temperature is used as aggregate, and the clinker fine powder is used for batching, kneading, molding, drying, and sintering to finally obtain the finished product.

Cast Zr-Containing Refractory Product

1) Use zircon concentrate or industrial zirconia and industrial alumina powder as raw materials.

2) Add sodium oxide, calcium oxide, boron oxide and rare earth metal oxides as additives.

3) The powder is melted at a temperature above 2500°C by means of electric arc melting, cast in a mold, cooled, annealed, and machined.

Non-fired Zr-Containing Refractory Product

The manufacturing process of zirconium-containing refractory products without firing is simple, and the product qualification rate is high.

1) Use stabilized zirconia clinker or zircon as raw material.

2) Use water glass, phosphoric acid, phosphate, or sulfate as the cementing agent.

3) Mix the raw materials and cementing agents, and undergo high-pressure molding and low-temperature heat treatment to make zirconium-containing non-fired materials.

The heat treatment temperature varies with different binders. When aluminum dihydrogen phosphate is used as the cement, the heat treatment temperature is about 300°C; when phosphoric acid is used as the cement, the heat treatment is carried out at a temperature of about 600°C.

What Are These Products Used for?

Zirconium-containing refractory products can be widely used in metallurgy, building materials, the chemical industry, machinery and other professional fields due to their high refractoriness, mechanical strength and chemical stability.

Zirconia bricks can be used in thermal equipment in the building materials industry and metallurgical industry, such as billet continuous casting sizing nozzles, submerged nozzles and slag lines in long nozzles.
Zircon bricks are resistant to low-alkali glass corrosion. They can be used for the kiln wall of the glass melting furnace, as well as the arch feet of the upper structure of the glass melting furnace or the intermediate transition layer between silica bricks and corundum bricks.
Zirconia-mullite fused cast bricks can be used in heating furnaces, soaking furnaces in the metallurgical industry, glass melting furnaces in the building materials industry, etc.
Zirconium corundum bricks have good resistance to melt erosion. As a high-grade abrasive, it has a good grinding effect on steel, cast iron, heat-resistant steel, and various alloy materials.

If you want to know more about zirconium material, we would like to advise you to visit Stanford Advanced Materials (SAM) for more information.