What Gas Is Used in Laser Cladding?

Which Gas Is Commonly Used in Laser Cladding?

Argon is widely used as a baseline process gas in powder-fed laser metal deposition because it is inert under typical cladding conditions and is established in industrial systems. It can be used as a carrier gas, a shielding gas or both, depending on the feeder and cladding-head design. However, the fact that argon is common does not make one argon setting suitable for every nozzle or material.

Helium and nitrogen are also discussed in laser cladding research, but they serve different purposes and carry different process implications. Helium is generally evaluated as a deliberate adjustment to heat transfer and gas-flow behaviour. Nitrogen is not chemically inert at high temperature; it can react with some alloys and change coating chemistry. It may be considered in a controlled, material-specific process route, not as a drop-in replacement for argon.

Gas	Where it may be evaluated	Main engineering consideration
Argon (Ar)	Common baseline for powder transport and local shielding.	Confirm gas purity, nozzle coverage, required flow and whether carrier and shielding circuits are separate.
Nitrogen (N₂)	Selected material systems where nitrogen uptake or nitride formation is an intentional objective.	Assess alloy chemistry, phase formation, hardness, corrosion response and application requirements.
Helium (He)	Selected deposition processes, sometimes as part of an argon-helium mixture.	Evaluate the effect on melt-pool behaviour, track geometry and gas-flow stability against the added supply cost.

The first checks should be the powder supplier’s process recommendation and the cladding-head manual. A gas mixture used in a published experiment should not be copied unless the material, nozzle geometry and process conditions are sufficiently comparable.

 

How Does the Workpiece Material Affect Gas Selection?

Material compatibility is often the deciding factor. The table below is a screening guide for planning trials; it is not a qualified procedure or a universal gas recipe.

Material or process case	Gas approach to evaluate	What to verify
Nickel-based alloys, such as IN718 or IN625	An argon-based carrier and shielding arrangement is a common baseline. An argon-helium mixture may be tested for a defined track-shape or heat-transfer objective.	Powder capture, oxidation, track height and width, dilution, microstructure, porosity and required properties.
Titanium alloys, such as TC4 / Ti-6Al-4V	Use a qualified protective-gas strategy. Nitrogen-containing mixtures are a separate, reactive process route and should only be considered where nitride formation is intended and validated.	Nitrogen uptake, TiN formation, hardness, corrosion behaviour, cracking and application suitability.
Iron- or cobalt-based hardfacing alloys	Begin with the powder supplier’s qualified shielding recommendation; argon is commonly evaluated.	Alloy chemistry, oxidation, dilution, cracking tendency and required wear properties.
High-speed coaxial deposition (EHLA)	Evaluate carrier-gas and shielding-gas flows together but control and record them as separate variables.	Powder focal length, focal-spot size, powder capture, particle trajectory and deposit geometry.

These examples should guide process screening, not replace material certificates, powder-supplier data, equipment specifications or procedure qualification. For reactive alloys, the gas atmosphere can become part of the coating chemistry rather than simply an external protective measure.

 

Is Argon the Best Gas for Laser Cladding?

Argon is a sensible first gas to evaluate for many powder-fed applications, but “best” depends on the process objective. In a 2018 study of laser metal deposition on Inconel 718, Ruiz and co-authors compared pure argon with argon-helium mixtures. Increasing the helium fraction reduced clad height and wetting angle under the reported test conditions, while other geometric changes were comparatively small. The study shows that gas composition can influence the deposited track, not only protect it from oxidation.

The result should not be interpreted as evidence that helium is always better. The experiments used a particular Inconel 718 powder, substrate, nozzle and set of laser parameters. A production decision should be based on controlled trials with the intended material and equipment.

Reference: Ruiz et al., “Study of the Influence of Shielding Gases on Laser Metal Deposition of Inconel 718 Superalloy,” Materials, 11(8), 1388 (2018). DOI: https://doi.org/10.3390/ma11081388

 

Can Nitrogen Be Used for Laser Cladding?

Yes, in selected and qualified applications. Unlike argon and helium, nitrogen can react with hot metal and change the phases that form in a coating. That reaction may be undesirable in one alloy system and useful in another. Nitrogen should therefore be treated as a reactive process choice, not a general-purpose substitute for argon.

A 2026 study examined laser cladding of TC4 titanium alloy powder onto a TC4 substrate under nitrogen-argon shielding mixtures. The researchers tested nitrogen fractions of 0%, 20%, 50% and 100%. Reported coating hardness increased from 390 HV0.2 under argon-only shielding to 510, 600 and 850 HV0.2 as the nitrogen fraction increased. The best corrosion resistance in that test series occurred at 20% nitrogen, not at the condition that produced the highest hardness.

Nitrogen fraction in shielding gas	Reported hardness	Reported observation
0%	390 HV0.2	Argon-only reference condition.
20%	510 HV0.2	Best corrosion resistance among the tested conditions.
50%	600 HV0.2	TiN-related phase formation became evident as nitrogen content increased.
100%	850 HV0.2	Highest hardness in the test series; not the best corrosion-resistance condition.

These values belong to the specific TC4-on-TC4 experiment and must not be transferred to nickel-, cobalt- or iron-based cladding powders. The study is an example of a deliberately engineered reactive atmosphere, not a recommendation to use nitrogen on general hardfacing applications.

Reference: Wang et al., “Effect of Shielding Gas Composition on Microstructure and Properties of Laser Cladding Layer on TC4 Titanium Alloy,” Materials Letters, 421, 141052 (2026). DOI: https://doi.org/10.1016/j.matlet.2026.141052

 

Can Helium Improve Laser Cladding Results?

Helium is used in selected laser deposition processes, sometimes blended with argon. Its physical properties can change heat transfer and the behaviour of the gas streams around the processing zone. In the Inconel 718 study cited above, the researchers tested pure argon, 75% argon plus 25% helium, and 50% argon plus 50% helium. Under their test conditions, increasing helium content reduced clad height and wetting angle and affected melt-pool temperature.

That is a process adjustment, not a universal upgrade. Before adopting an argon-helium blend, identify the measurable benefit required—such as a particular track profile or melt-pool response—and compare it with the additional gas cost and supply requirements.

 

What Is the Difference Between Carrier Gas and Shielding Gas?

Carrier gas and shielding gas perform different jobs. A machine may use the same gas species for both functions, but the two flows should not be treated as one setting.

•  Carrier gas transports powder from the feeder through the delivery line and nozzle. Its flow affects particle velocity, powder-stream convergence and the amount of powder captured by the melt pool.
•  Shielding gas creates a protective atmosphere around the melt pool and hot deposit. Its purpose is to limit exposure to surrounding air and reduce oxidation or contamination.

In a coaxial powder-fed head, the powder stream and protective gas may travel through separate passages and meet around the processing zone. Side-feed heads use a different arrangement. The actual torch drawing—not a generic diagram—should be used to identify the gas paths before any setting is changed.

The distinction also matters when diagnosing a problem. A broad or unstable powder stream may point to carrier-gas flow, powder condition, a blocked line or nozzle alignment. Surface oxidation may instead involve shielding coverage, gas purity, leaks, stand-off distance or ambient air movement. One symptom can have several causes, so avoid changing multiple gas settings at once.

For more detail on powder delivery and coaxial arrangements, see the OurCladding article on coaxial powder feeding laser cladding. [coaxial powder feeding laser cladding article]

 

How Should the Powder Feeder and Cladding Head Be Configured?

The powder feeder and cladding head form one delivery system. Their gas connections, flow paths and adjustment ranges need to be considered together. A feeder specification alone does not define the shielding-gas requirement at the processing point, and a flow value from one feeder should not be treated as a universal setting for another machine.

Check the carrier-gas path

Confirm the gas inlet, hose diameter and length, powder delivery line, feeder arrangement and nozzle connection. Check that the selected gas is compatible with the powder supplier’s recommendation and the equipment specification. If powder delivery becomes unstable, inspect powder condition, moisture or contamination, line restrictions, leaks and nozzle wear before assuming that the gas supply is the only cause.

Check the shielding-gas path

Identify where shielding gas enters and exits the cladding head, how the flow covers the melt pool and hot deposit, and whether the flow can be adjusted independently of the carrier gas. Verify that the nozzle design and stand-off distance provide suitable coverage for the workpiece geometry. A flow meter reading does not, by itself, prove that the processing zone is adequately shielded.

Confirm the actual machine configuration

Before specifying equipment, ask the supplier to confirm the gas connections, available controls and compatible cladding-head arrangement for the selected machine. On the OurCladding powder-feeder page, use the published connection and control information only for the feeder configuration shown. Do not interpret a feeder-side powder-gas parameter as the shielding-gas flow rate unless the technical documentation explicitly identifies it that way.