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Metal powders are vital in industry. Find out more about ultrasonic atomization for better control of particle size and shape and higher purity powders.
Metallic powders are tiny particles of metal that are typically less than 150 micrometers in size. Various alloys in powder form are a versatile and essential materials in a wide range of industries, with application in fields such as powder metallurgy, additive manufacturing, thermal coatings, soldering and brazing. One of the key advantages of using metal powders is their ability to be shaped and formed into a variety of different products, from simple parts to complex geometries.
Important aspect to consider when working with metal powders is the particle size and shape of the powder. The particle size and shape can affect the flowability and packing density of the powder, which in turn affects the properties of the final product. For example, spherical metal powders tend to have a higher packing density and better flowability compared to irregularly shaped powders. Additionally, the particle size can also affect the surface area of the powder, which can impact the reactivity or catalytic activity of the powder.
Reliable metal powder suppliers are critical for ensuring high-quality metal powder for various applications. Custom powdered metal can be created to meet specific manufacturing needs, including tailored chemical compositions and powder production designed methods to meet quality requirements such as particle size distribution, contamination, sphericity, etc.
The quality of the powders is critical for the production process. In order to minimize defects and ensure consistency, it is important to use high-quality powders with minimal impurities, and that are well-controlled for particle size and shape distribution. This can be achieved by using high quality materials, advanced processing techniques and quality control methods.
Metallic powders are used in a variety of metal additive manufacturing processes (AM), such as powder bed fusion, binder jetting, and directed energy deposition.
In powder bed fusion (PBF) processes, such as selective laser melting (SLM) and electron beam melting (EBM), a layer of metallic powder is spread over a build platform and a focused energy source, typically a laser or electron beam, is used to melt and fuse the powder particles together.
In binder jetting, a binder is selectively deposited onto a bed of metallic powder, bonding the powder particles together to form the desired shape.
In directed energy deposition (DED), a focused energy beam, such as a laser or an electron beam, is directed onto a substrate while simultaneously depositing a stream of metallic powder.
All these methods allow for the creation of complex geometries and high-resolution parts with high accuracy and precision, and the powders can be made from a variety of metals, including iron, copper, aluminum, nickel, titanium alloys as well as precious and refractory metals.
In addition to powder additive manufacturing process, metal powders are also used in other industrial applications such as thermal coatings, thermal spraying, soldering, and brazing. For example, in thermal spraying, metal powders are heated to a high temperature and then propelled onto a surface to create a wear-resistant and corrosion-resistant coating.
In soldering and brazing, metal powders are used to join metal components together by creating a strong and reliable bond.
Overall, metallic powders are a versatile and essential material in a wide range of industries, and the quality of the powders is crucial for ensuring consistent and reliable performance in the final products. It’s important to have a reliable supplier and to have control over the particle size, shape and chemical composition of the powders.
One popular manufacturing method for metal powders is atomization, which involves breaking up a molten metal stream into small droplets that solidify into spherical powder particles. This method is commonly used for the production of alloy powders, as it allows for precise control over the chemical composition of the powder. There are several atomization techniques used to manufacture metal powders.
Metal atomization is a process used to produce metal powders for various industries such as aerospace, automotive, electrical, or medical sectors. It is usually used for powder metallurgy, additive manufacturing, soldering, and brazing or coating technologies. The process involves various media for this purpose, which breaks the stream or melt pool into fine molten metal droplets that solidify into powder particles. The quality, size, and shape of resulting powder particles highly depend on the atomization technique used. The most desired parameters of powder are a narrow particle size distribution and a spherical shape, which are crucial properties for many powder-based applications.
There are several metal atomization systems and manufacturing processes for powder atomization, including gas atomization, water atomization, centrifugal atomization, ultrasonic atomization, and plasma spheroidization. Each method has its own unique advantages and disadvantages and is best suited for specific applications and materials.
One of the most commonly used methods for metal pulverization is gas atomization, which is a widely used method for producing metal powders, and it can be used to process various metals and alloys. There are several variations of the gas atomization process, two of the most popular are: vacuum induction gas atomization (VIGA) and electric induction gas atomization (EIGA). These processes are widely use as large scale production technologies and are known for producing good quality powders with relatively high degree of sphericity. Gas atomized powders are also characterized with wide particle size distribution.
Vacuum Induction Gas Atomization (VIGA) process uses a stream of inert gas to atomize the molten metal under a vacuum.
One of the main applications of VIGA is in the production of powders for metal additive manufacturing. Other applications include powders for coatings, hardfacing, brazing and sintering. VIGA can be used to produce powders of various metals such as nickel superalloys, cobalt chromium, and steel alloys (tool steels, stainless steels).
The Electric Induction Gas Atomization (EIGA) process uses an electric induction to heat the metal rod, which is then atomized by the high pressure inert gas.
EIGA can be used to produce powders of various metals, mostly for titanium, aluminum, zirconium, niobium, tantalum and platinum alloys.
The cons of both VIGA and EIGA are that it requires gas atomizers which are large and high-cost equipment and it may be more challenging to produce powders with a wide range of compositions using these methods. Additionally, the consumption of intert gas in the process is very high.
Water atomization is a method for producing metal powders where a stream of molten metal is atomized by a high-pressure water. This process is known for producing powders with a wide range of particle sizes and a variety of shapes, including spherical and irregular particles.
One of the main applications of water atomization is in the production of iron and its alloys (tool steels, alloy steels), copper and its alloys (bronze, brass) as well as materials with lower melting point like tin, lead, zinc, cadmium and aluminium.
The pros of water atomization include that it can produce powders with a wide range of particle sizes, and it is suitable for producing powders of various metals and alloys.
The cons of water atomization include that it is less efficient than other methods, and the powders produced may have a lower degree of sphericity and less uniformity in particle size and shape. Additionally, it requires large amounts of water and generates a significant amount of waste water.
Centrifugal atomization is a method for producing metal powders where a stream of molten metal is sprayed by spinning it at high speeds using a centrifugal force. This process is known for producing powders with a narrow range of particle sizes and a high degree of sphericity.
Centrifugal atomization can be used to produce powders of various metals such as solders, magnesium, aluminum, copper, stainless steel and titanium (PREP).
The pros of centrifugal atomization include that it can produce highly spherical powders, narrow powder size, and it can be used to produce powders of various metals including titanium in PREP type process.
The cons of centrifugal atomization include that it requires specialized high-cost equipment, and it may be more challenging to produce powders of refractory metals.
Ultrasonic atomization is a method that uses high-frequency ultrasonic waves to atomize the molten. Ultrasonic atomization process is a relatively new method for metal atomization, which can provide greater control over the particle size and shape of powders, and produce powders with a higher degree of purity. The process is suitable for laboratory and low production scale and allows to atomize various types of feedstock starting from a few grams. This technology is mostly used for creating metal alloys powders with tailored chemical composition.
Due to different possible heat sources and type of proceses, the ultrasonic atomization process can be used to atomize nearly all alloying systems including low melting and volatile elements and alloys as well as reactive and difficult to atomize metals and alloys, such as titanium or refractory metal alloys. Ultrasonic production process allows to create highly spherical powders with various size range (narrow particle size controlled by frequency), lack of satellites and very fine powder particles and low contamination.
One of the main advantages of ultrasonic atomization is the quality of the powder mentioned above as well as very wide scope of materials that can be processed. The size of the powder can be controlled by the frequency of vibrations allowing to manufacture various powder sizes suitable for selected technology. From economic point of view, the equipment is affordable and does not take up much space, which allows it to be installed in most laboratories. In addition, the device consumes small amounts of gas and electricity.
One of the biggest disadvantage of the process is low scalability at current stage making it a process suitable mostly for laboratory applications and new materials development or small in house production scale.
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