How Are Metal Powders Made

Metal powders are produced using four primary categories of manufacturing processes: Atomization (Physical), Solid-State Reduction (Chemical), Electrolysis, and Mechanical Comminution. Among these, Atomization is the most dominant method for modern high-performance applications, where a stream of molten metal is disintegrated into fine droplets by high-pressure jets of water or gas. Solid-State Reduction involves chemically removing oxygen from metal oxides (usually iron) to create a sponge-like powder. Electrolysis utilizes electrical current to deposit high-purity metal powders from a solution, often used for copper. Finally, Mechanical Comminution employs milling or grinding techniques to physically crush brittle metals or alloys into powder. The specific manufacturing process selected dictates the powder’s particle shape (spherical vs. irregular), purity, and density, which in turn determines its suitability for downstream applications like 3D printing (AM), Metal Injection Molding (MIM), or Press and Sinter.

Atomization Method

Atomization is currently the most popular technology, especially in industries that are extremely critical of material performance, such as aerospace and medical device manufacturing. This is the physical process; the core logic is to use high-energy fluid to impact the molten metal stream.

In actual operation, we usually subdivide the “impact medium” into two categories according to the difference, and the application scenarios of the two are very different:

• Gas Atomization: This is the process of bombarding the metal stream with an inert gas (such as nitrogen or argon). The finished product is very beautiful—highly spherical with a smooth surface. In my experience, precisely because the particles are round, their high packing density and excellent flow make aerosolized powders the industry standard for additive manufacturing (3D printing) and metal injection molding (MIM). If you want to print a precision piece, you have no choice but to use this.
• Water Atomization: here is the use of high-pressure water jet to treat molten metal. Because the cooling rate of water is too fast, the metal particles solidify before they can be rounded, so the shape is very irregular and the surface is rough. Although the fluidity is not as good as that of aerosolized powder, in my opinion, this “disadvantage” is its advantage—during the pressing process, the irregular shape can cause mechanical occlusion between the particles. Therefore, in pressing and sintering applications, if you value the “green strength” of the part (i.e., the strength before sintering), water atomized powder is the first choice.

Solid State Reduction Method

Solid state reduction is the chemical method. When it comes to this, everyone will basically think of iron powder production. Unlike the atomization method of melting metal, this thing plays with solids.

The whole process usually looks like this:

• Raw material preparation: The ore is crushed and mixed with a reducing agent (usually coke or charcoal as a carbon source).
• Reaction: The mixture is heated in a kiln, and the temperature is controlled below the melting point of iron. At this time, the reducing agent began to work, the oxygen in the iron oxide “grab” away.
• The result: the last remaining a porous, sponge-like structure of metallic iron. After crushing and screening these “sponge iron”, the finished product is obtained.

From an engineering point of view, this porous structure has a huge advantage: it can absorb oil. Therefore, this powder is particularly suitable for the manufacture of self-lubricating bearings, or those requiring high compressibility of the structural parts.

Electrolysis

When the project at hand has rigid requirements for conductivity or chemical purity, electrolysis is the only way out. This method is most commonly used to produce copper powder.

Its principle is similar to electroplating, simply put:

• Setting: Throw the metal plate (anode) into the electrolytic cell containing the metal sulfate solution.
• Deposition: After energization, the metal on the anode dissolves, passes through the electrolyte, and is deposited on the cathode.
• Powder: after a period of time to deposit down the metal scraping, cleaning, drying, grinding.

The electrolytic powder is very characteristic under the microscope, showing dendritic (fern-like) and extremely pure. This is why they are almost irreplaceable in electronic applications such as conductive inks and motor brushes.

Mechanical Crushing Method

Mechanical crushing method is a “heterogeneous”, it purely by mechanical force to smash solid metal. This method is usually reserved for brittle metals (such as beryllium, antimony, bismuth) or brittle alloys. The reason is simple—if you smash a malleable metal, it will only flatten, not break.

Common means include:

• Ball milling: Throwing a metal block into a rotating drum and crushing the material with hard ceramic or steel balls inside.
• Grinding: Use heavy-duty grinding wheels to grind.

To be honest, this method has a headache: easy to introduce impurities (after all, grinding ball will wear). However, the current technology is also advancing, such as high-energy ball milling (mechanical alloying), which can weld and interrupt different materials at the atomic level to produce some interesting composite powders.

How Does The Manufacturing Process Determine The Final Application?

Understanding “how metal powder is made” is not an endorsement, but because the production method directly locks in the physical properties of the powder—especially particle shape, purity and density.

Spherical powder (aerosolized): Staring for 3D printing and MIM. The ball ensures that the powder spreads flat and flows smoothly.

Irregular/spongy powder (water atomization/solid state reduction): stared pressed for sintering. The rough surface allows the particles to “bite” each other, and the pressed parts are not easy to fall apart.

Dendritic/high purity powder (electrolysis): looking at high-end electrochemical applications, purity and conductivity are not negotiable.

In the final analysis, whether it is the physical violence of atomization and crushing, the chemical reaction of reduction method, or the electrochemical deposition of electrolysis method, the core is to lock the performance through the process to ensure that the final metal parts do not fall off the chain.

Author ： Alex Miller

With over 17 years in materials engineering, I specialize in powder metallurgy. I share professional insights on how atomization and reduction processes shape the metal powders used in modern additive manufacturing and industrial applications.