gas atomization metal powder

Gas atomization metal powder refers to a material processing method to produce fine spherical metal powders for applications like metal injection molding (MIM), additive manufacturing, pressing and sintering, thermal spray coatings, powder metallurgy, and more.

In gas atomization, molten metal alloys are disintegrated into droplets using high pressure inert gas jets. The droplets rapidly solidify into powder, yielding highly spherical morphologies ideal for powder consolidation processes.

This guide covers gas atomized metal powder compositions, characteristics, applications, specifications, production methods, suppliers, pros vs cons, and FAQs to consider.

Composition of Gas Atomized Metal Powders

Various metals and alloys with tailored chemistries are atomized into powders:

Material	Composition Overview	Common Alloys
Stainless steel	Fe-Cr + Ni/Mn/Mo	304, 316, 410, 420
Tool steel	Fe-Cr-C + W/V/Mo alloys	H13, M2, P20
Aluminum alloy	Al + Cu/Mg/Mn/Si	2024, 6061, 7075
Titanium alloy	Ti + Al/V alloys	Ti-6Al-4V
Nickel alloy	Ni + Cr/Fe/Mo alloys	Inconel 625, 718
Copper alloy	Cu + Sn/Zn/alloys	Brass, bronze

These metal powders offer specific mechanical, thermal, electrical and other physical properties for manufacturing needs.

Characteristics of gas atomization metal powder

In addition to chemistry, characteristics like particle size, shape, density, and microstructure determine performance:

Attribute	Description	Considerations
Particle size distribution	Range/distribution of diameters	Impacts minimum feature resolution, packing efficiency
Particle morphology	Powder shape/surface structure	Rounded, smooth particles provide best flow and handling
Apparent density	Weight per volume including interparticle voids	Influences compactability and clustering
Tap density	Settled density after mechanical tapping	Relates to ease of powder bed compaction
Surface chemistry	Surface oxides, residual gases or moisture	Affects powder stability and consistency
Microstructure	Grain size/phase distribution	Determines properties like hardness, ductility after consolidation

These interconnected aspects are balanced for needs.

Applications of gas atomization metal powder

The consistent material input and net shaping capabilities support diverse applications:

Industry	Uses	Component Examples
Additive manufacturing	3D printing feedstock	Aerospace airfoils, medical implants
Metal injection molding	Small intricate metal parts	Nozzles, gears, fasteners
Press and sinter	P/M component production	Structural auto parts, military/firearm components
Thermal spray	Surface coatings	Anti-wear, anti-corrosive overlays
Powder metallurgy	Oilite bearings, self-lubricating bushings	Wear components with porous structures

Gas atomization provides unique access to tailor microstructures and chemistries suited to end-performance needs.

Specifications

While application-specific, common nominal ranges include:

Parameter	Typical Range	Test Method
Particle size distribution	10 – 250 μm	Laser diffraction, sieve
Particle shape	>85% spherical	Microscopy
Apparent density	2 – 5 g/cm3	Hall flowmeter
Tap density	3 – 8 g/cm3	Tapping volumeter
Residual gases	< 1000 ppm	Inert gas analysis
Surface oxide content	< 1000 ppm	Inert gas analysis

Tighter distribution curves ensure reliable performance in subsequent processes.

Gas Atomization Production Overview

1. Charge induction furnace with raw materials like metal ingots, waste scrap
2. Melt material; sample chemistry and temperature
3. Force molten metal stream into close-coupled gas atomizer nozzle(s)
4. Shape smooth liquid metal stream(s)
5. High velocity inert gas jets (N2, Ar) disintegrate stream into droplets
6. Metal droplets rapidly solidify into powder ~100-800 μm
7. Thermally classify coarse fractions via cyclone separators
8. Collect fine powders in collection system and bins
9. Sieve classify into size fractions as needed
10. Package/store material with inert backfill

Precisely controlling all aspects of this process is key to consistency.

gas atomization metal powder Suppliers

Many leading global material producers offer gas atomization manufacturing:

Supplier	Materials	Description
Sandvik	Tool steels, stainless steels, superalloys	Broad range of gas atomized alloys
Carpenter Technology	Tool steels, stainless steels, specialty alloys	Custom alloys available
Höganäs	Tool steels, stainless steels	Global leader in atomization
Praxair	Titanium alloys, superalloys	Reliable supplier of precision materials
Osprey Metals	Stainless steel, superalloys	Focus on reactive and exotic alloys

Volume pricing depends on market conditions, lead times, exotic material charges, and other commercial factors.

Tradeoffs When Considering gas atomization metal powder

Pros:

• Consistent spherical morphology
• Narrow particle size distributions
• Known and uniform input chemistry
• Controlled, clean material microstructure
• Ideal flow characteristics for AM deposition
• Allows thin walls/intricate geometries

Cons:

• Requires significant up front capital infrastructure
• Limited alloy availability vs water atomization
• Special handling to prevent contamination
• Costs more than alternate methods at production volumes
• Lower yield than alternate processes
• Limited capacity for ultrafine particle sizes

For critical applications, gas atomized powder provides unique advantages related to consistency and performance.

Frequently Asked Questions

What is the key difference between gas and water atomization?

Gas atomization relies purely on inert gas jets to disintegrate molten metal into powder whereas water atomization uses water sprays interacting with gas jets, yielding faster cooling rates but more irregular powder.

What is the narrowest particle size distribution achievable?

Specialized nozzles, tuning, and classifier stages allow particle size distributions down to D10: 20 μm, D50: 30 μm, D90: 44 μm for gas atomization. Even tighter ranges continue to be developed.

How small can gas atomization nozzles get?

Nozzle bore sizes down to 0.5 mm have been developed to produce batch volumes less than 1 kg per hour. Though free-fall type powder classification remains challenging below 20 μm sizes.

What affects consistency between powder batches?

Control over composition, cleanliness, temperature profiles, gas pressures, atomization conditions, and powder handling/storage all contribute to reproducibility. Tight process control is essential.

What is the typical powder yield relative to initial mass?

For common alloys and size ranges, yield percentages typically span 50-85% depending on desired distribution widths and acceptable fraction outs. Finer distributions have lower yields.

know more 3D printing processes