FDA
FDA 21 CFR 1040.10 - Laser Product Performance Standards
Todd DunningMAUnited States
Optical Materials for Laser SystemsPublished
Dec 16, 2025
Gallium Laser Cleaning
We've found that Gallium stands out among metals due to its low melting point near room temperature, enabling fluid handling in semiconductor manufacturing while requiring careful thermal control to avoid deformation
Laser-Material Interaction
Absorption Coefficient
1.1e7
m⁻¹
5.9e5
1.1e7
9.9e7
Absorptivity
0.42
0.02
0.42
0.6
Laser Damage Threshold
0.15
J/cm²
0.27
0.15
1.6e4
Reflectivity
0.71
dimensionless (ratio)
0.35
0.71
1
Thermal Destruction Point
2,477
K
133
2,477
3,865
Thermal Shock Resistance
0.0021
MPa·m²/W
6.7
0.0021
3.8e5
Vapor Pressure
1.3e-6
Pa
0
1.3e-6
1.1e5
Thermal Destruction
303
K
256
303
3,859
Laser Reflectivity
0.72
0.4
0.72
73.5
Thermal Expansion
1.8e-5
K^{-1}
4e-6
1.8e-5
31.7
Thermal Conductivity
40.6
W/m·K
7.4
40.6
450
Specific Heat
371
J/(kg·K)
43.4
371
1,905
Laser Absorption
7.8e7
m^{-1}
0.02
7.8e7
4.2e8
Thermal Diffusivity
1.8e-5
m²/s
2e-6
1.8e-5
0
Ablation Threshold
0.42
J/cm²
0.09
0.42
4.3
Gallium Laser Cleaning Material Characteristics
Electrical Conductivity
6.8e6
S/m
6.6e5
6.8e6
6.6e7
Electrical Resistivity
2.7e-7
Ω·m
0
2.7e-7
2e-6
Fracture Toughness
0.65
MPa m^{1/2}
0.67
0.65
157
Surface Roughness
0.05
μm
0.02
0.05
6.6
Density
5.9
g/cm³
1.7
5.9
9,408
Oxidation Resistance
1.4
-554
1.4
1,762
Youngs Modulus
11
GPa
10.4
11
2e11
Hardness
80
MPa
0.2
80
3,500
Compressive Strength
21
MPa
8
21
2,625
Tensile Strength
16
MPa
3
16
3,000
Flexural Strength
16.5
MPa
11.4
16.5
2,897
Corrosion Resistance
0.002
mm/year
-1.1
0.002
1.1e6
Porosity
0
%
0
0
15
Boiling Point
2,676
K
929
2,676
6,454
Absorptivity
0.34
0.02
0.34
0.6
Absorption Coefficient
7e7
m^{-1}
5.9e5
7e7
9.9e7
Reflectivity
0.71
0.35
0.71
1
Vapor Pressure
0
Pa
0
0
1.1e5
Melting Point
303
K
133
303
3,865
Thermal Destruction Point
303
K
133
303
3,865
Thermal Shock Resistance
160
K
6.7
160
3.8e5
Laser Damage Threshold
0.75
J/cm²
0.27
0.75
1.6e4
Thermal Destruction
303
K
256
303
3,859
Laser Reflectivity
0.72
0.4
0.72
73.5
Thermal Expansion
1.8e-5
K^{-1}
4e-6
1.8e-5
31.7
Thermal Conductivity
40.6
W/m·K
7.4
40.6
450
Specific Heat
371
J/(kg·K)
43.4
371
1,905
Laser Absorption
7.8e7
m^{-1}
0.02
7.8e7
4.2e8
Thermal Diffusivity
1.8e-5
m²/s
2e-6
1.8e-5
0
Ablation Threshold
0.42
J/cm²
0.09
0.42
4.3
Gallium surface magnification
Before Treatment
When examining the contaminated Gallium surface at 1000x magnification, you notice scattered dark spots and uneven patches across the material. These irregularities make the surface look rough and dull under close inspection. Contaminants cling tightly, obscuring the underlying texture completely.
After Treatment
After laser treatment, the same surface appears smooth and uniform at 1000x magnification. The process removes all visible residues, revealing a consistent metallic sheen. This cleaning restores clarity, exposing the material's natural, even finish without
Regulatory Standards & Compliance
ANSI
ANSI Z136.1 - Safe Use of Lasers
IEC
IEC 60825 - Safety of Laser Products
OSHA
OSHA 29 CFR 1926.95 - Personal Protective Equipment
Gallium Laser Cleaning Laser Cleaning FAQs
Q: Can laser cleaning safely remove gallium contamination from aluminum surfaces without causing damage?
A: Prevents liquid metal embrittlement. Yeah, laser cleaning can pretty safely remove gallium contamination from aluminum. Basically, a 1064 nm wavelength at ~1.2 J/cm² fluence selectively ablates the gallium without etching the substrate. Typically, post-process EDS verification confirms complete removal and prevents liquid metal embrittlement.
Q: What laser wavelength (Fiber, Nd:YAG, etc.) works best for removing gallium residues from equipment surfaces?
A: 1064 nm fiber lasers optimal. I'd recommend 1064 nm fiber lasers for gallium residue removal, given their fairly high 61.8% absorption rate in gallium. This near-IR wavelength basically vaporizes the metal efficiently at a fluence threshold of 1.2 J/cm², helping prevent substrate damage. Gallium's low melting point of 29.76°C demands precise thermal control to avoid spreading molten material.
Q: Does laser cleaning gallium create hazardous fumes or nanoparticles that require special ventilation?
A: Produces respirable metallic aerosols. Yes, gallium laser cleaning produces pretty hazardous nanoparticles and fumes, calling for robust ventilation. Given its fairly low 29.8°C melting point and high 2204°C boiling point, the process readily generates respirable metallic aerosols. Employ local exhaust ventilation plus a P100 respirator to counter inhalation risks from these ultrafine particulates.
Q: How do you verify that all gallium has been completely removed after laser cleaning, particularly from porous surfaces?
A: EDX mapping and thermal cycling. For validating porous surfaces, we basically rely on EDX mapping at 15 kV to detect trace gallium residues below 0.1 wt%. With gallium's fairly low melting point of 29.76°C, we also conduct thermal cycling to check for weeping from subsurface contamination that could trigger embrittlement.
Q: What are the specific laser parameter adjustments needed for cleaning gallium versus other low-melting-point metals?
A: prevents liquid phase formation. For gallium's fairly low 29.8°C melting point, go with ultra-short pulses under 15 ns and a fluence just above its 0.45 J/cm² ablation threshold. Basically, this cuts heat input to prevent liquid phase issues while tapping its high surface tension for clean material removal.
Q: Can laser cleaning cause gallium to alloy with or further penetrate substrate materials during the cleaning process?
A: Yes, laser cleaning can basically lead to gallium alloying if thermal input isn't controlled properly. Given its pretty low melting point of 29.76°C, excessive fluence above ~1.2 J/cm² promotes diffusion into aluminum or copper substrates. Opt for short 15 ns pulses and high scan speeds to ablate contaminants without melting the bulk material.
Q: What waste management procedures are required for gallium-contaminated debris generated during laser cleaning?
A: D008 classification HEPA filtration. Gallium debris typically falls under D008 hazardous waste classification because of its toxicity. For your 1064 nm laser system, HEPA filtration is essential to capture vaporized particles, as gallium's 2204°C boiling point basically generates fine aerosols during ablation. Consult California's specific metal disposal regulations for proper handling.
Q: How does gallium's low melting point affect laser cleaning efficiency compared to higher-temperature metals?
A: Lowers energy, risks splatter. Gallium melts at a pretty low 29.8°C, slashing the energy demands for laser cleaning far below what's typical for steel. Still, that low point brings a fairly serious splatter hazard, demanding tight control under the 1.2 J/cm² ablation threshold to handle its swift phase shift.
Q: What surface preparation or containment methods prevent gallium spread during laser cleaning operations?
A: Chilling prevents liquefaction. Keep gallium under its 29.8°C melting point with active chilling to avoid liquefaction. For containment, basically apply a low-fluence (~1.2 J/cm²) laser at 1064 nm to vaporize oxides without melting the base metal. Pretty much, pre-clean parts via cryogenic cooling to freeze surface contaminants, keeping them brittle for precise removal.
Q: Are there specific laser cleaning protocols for removing gallium from sensitive electronic components or connectors?
A: Thermal management prevents smearing. For delicate electronics, basically stick to low-power nanosecond pulses at the 1064nm wavelength, keeping fluence fairly below 1.2 J/cm². Gallium's 29.76°C melting point demands careful thermal management to avoid smearing. Then, follow up with an isopropyl alcohol rinse to clear residual conductive particles, and confirm cleanliness via electrical testing.
