Thermal Spray Coating laser cleaning visualization showing process effects

Alessandro MorettiPh.D.Italy

Laser-Based Additive Manufacturing

Published

Jan 6, 2026

Thermal Spray Coating

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Plasma-spray contamination arises during the thermal deposition process, where molten particles adhere unevenly to substrates. This contamination, it manifests as tenacious oxide layers, which exhibit regional variations influenced from substrate geometry. On metals like steel, the deposits persist densely, showing heat-resistant bonds that resist initial laser pulses. Ceramics, by contrast, display fragmented patterns, less adherent yet prone to microcracking under exposure. Removal challenges emerge distinctly; the contamination adheres stubbornly to ferrous materials, demanding prolonged irradiation to dislodge, while on non-metallics, it disperses more readily but leaves residual roughness. It appears that laser cleaning yields incomplete results on uneven surfaces, where shadows hinder uniform ablation. These behaviors, they highlight the need for tailored wavelengths, as confirmed by surface scans. The process effectively mitigates thermal damage, though adhesion varies regionally.

Produced Compounds

Hazardous compounds produced during laser cleaning

Affected Materials

Materials where this contaminant commonly appears

Visual Appearance

How this contaminant appears on different material categories

AppearanceOnCategories

Ceramic

Appearance: The coating appears as a rough, matte finish in colors like gray or black, sometimes with a speckled look from embedded particles.
Coverage: Coverage is generally high and even, designed for full surface protection, though edges may have slight variations.
Pattern: Distribution is often uniform or slightly mottled, but can show streaks or patches if application is uneven.

Composite

Appearance: On composites, it appears as a rough, heterogeneous layer in mixed colors, blending with the substrate but showing texture variations.
Coverage: Coverage varies widely, from partial to full, with inconsistencies at joints or curved areas.
Pattern: Distribution is patchy or streaked, influenced by the composite's fiber orientation and surface properties.

Concrete

Appearance: It looks like a coarse, gritty coating in gray or earth tones, blending with the surface but adding a rough, sometimes glossy sheen.
Coverage: Coverage is typically high and uniform for protection, but can vary on rough or uneven surfaces.
Pattern: Patterns are mottled or streaked, influenced by concrete's porosity and application technique.

Fabric

Appearance: On fabric, it appears as a stiff, crusty deposit in dull hues, embedding into fibers and altering the texture to a rough feel.
Coverage: Coverage is partial and variable, often limited to surface contact points with gaps in between.
Pattern: Distribution is blotchy or streaky, following the weave pattern and leading to uneven spots.

Glass

Appearance: On glass, it manifests as a hazy, opaque layer with a rough texture, often in white, gray, or translucent colors that obscure transparency.
Coverage: Coverage is typically low and non-uniform, as the smooth surface resists coating, leading to gaps and variations.
Pattern: It forms streaky or blotchy patterns, with poor adhesion causing peeling or beading in spots.

Metal

Appearance: Thermal spray coating on metal appears as a rough, matte to semi-gloss layer, often in metallic gray, black, or colored hues depending on the coating material.
Coverage: Coverage is usually high and consistent, aiming for full surface protection, but variations can occur at edges or complex geometries.
Pattern: It typically forms a uniform or slightly streaked pattern, with occasional spatter spots or uneven patches due to application inconsistencies.

Mineral

Appearance: On minerals, it appears as a rough, adherent layer in colors matching or contrasting the substrate, such as metallic or dark shades.
Coverage: Coverage ranges from partial to full, with variations due to natural irregularities in the mineral surface.
Pattern: Distribution is often uniform or patchy, depending on the mineral's crystal structure and surface smoothness.

Plastic

Appearance: It looks like a brittle, flaky layer in dull colors such as gray or beige, often cracking or peeling due to thermal expansion mismatches.
Coverage: Coverage is low and uneven, with frequent gaps and poor adhesion causing partial coverage.
Pattern: Patterns are irregular with spots and patches, as the coating may not bond well, leading to delamination.

Rubber

Appearance: It manifests as a cracked, peeling film in colors like black or gray, often looking brittle and mismatched with the flexible rubber surface.
Coverage: Coverage is generally low and non-uniform, with the coating failing to cover the entire surface evenly.
Pattern: Patterns are irregular with flaking spots and streaks, due to poor adhesion and elasticity differences.

Semiconductor

Appearance: It manifests as a thin, often discolored film in shades like gray or brown, with a smooth to slightly rough texture that may interfere with electronic properties.
Coverage: Coverage is usually controlled and even for functional layers, but contamination leads to partial, undesirable coverage.
Pattern: Patterns are typically uniform or speckled, but can show defects like streaks or spots from contamination.

Specialty

Appearance: On specialty materials, it appears variable—rough or smooth in diverse colors—tailored to the substrate but often looking out of place.
Coverage: Coverage is highly variable, designed for specific needs but prone to inconsistencies if not optimized.
Pattern: Distribution depends on the material; it can be uniform, patchy, or streaked, based on application and adhesion.

Stone

Appearance: It appears as a gritty, uneven film in shades like gray or tan, sometimes glossy if sealed, but often rough and discolored.
Coverage: Coverage varies from partial to full, but tends to be inconsistent, with thinner areas on rough surfaces.
Pattern: Patterns are irregular with patches and streaks, influenced by the stone's porosity and surface irregularities.

Wood

Appearance: On wood, it looks like a coarse, flaky overlay with colors ranging from dull gray to brown, often contrasting with the natural grain and texture.
Coverage: Coverage is generally low and uneven, with gaps exposing the wood surface due to poor adhesion and material incompatibility.
Pattern: Distribution is patchy or streaky, as the coating may not adhere well, leading to flaking and irregular spots.

Laser Removal Properties

Laser parameters and removal characteristics

LaserParameters: BeamProfile
flat_top
FluenceRange
maxJCm2: 3
minJCm2: 1.5
recommendedJCm2: 2
OverlapPercentage
50
Polarization
circular
PulseDurationRange
maxNs: 200
minNs: 10
recommendedNs: 50
RepetitionRateKhz
max: 200
min: 20
recommended: 50
SafetyMarginFactor
0.7
ScanSpeedMmS
max: 2000
min: 500
recommended: 1000
SpotSizeMm
max: 0.1
min: 0.03
recommended: 0.05
WavelengthPreference
0: 1064
1: 532
OpticalProperties: AbsorptionCoefficient
wavelength1064Nm: 8500
wavelength532Nm: 48000
Reflectivity
wavelength1064Nm: 0.35
wavelength355Nm: 0.08
wavelength532Nm: 0.18
RefractiveIndex
imaginaryPart: 0.15
realPart: 2.4
TransmissionDepth
11.8
RemovalCharacteristics: Byproducts
0: [object Object]
1: [object Object]
2: [object Object]
DamageRiskToSubstrate
medium
PrimaryMechanism
thermal_ablation
ProcessSpeed
areaCoverageRateCm2Min: 240
typicalScanSpeedMmS: 800
RemovalEfficiency
diminishingReturnsAfter: 6
optimalPasses: 4
singlePass: 0.3
SecondaryMechanisms
0: mechanical_spallation
1: thermal_stress_fracturing
SurfaceQualityAfterRemoval
colorChange: yes
residualStress: compressive
roughnessIncrease: moderate
SafetyData: FireExplosionRisk
severity: low
description: Minimal fire risk with standard precautions and adequate ventilation
mitigation: Standard fire safety precautions, extinguisher available within 15m
FumesGenerated
0: [object Object]
1: [object Object]
2: [object Object]
ParticulateGeneration
respirableFraction: 0.7
sizeRangeUm: 0.1,10
PpeRequirements
eyeProtection: goggles
respiratory: PAPR
skinProtection: full_suit
rationale: Standard protection against workplace hazards
SubstrateCompatibilityWarnings
0: May generate toxic fumes if coating contains heavy metals
1: Potential for substrate material to vaporize and create additional hazards
2: Watch for reflective surfaces causing laser beam deflection
ToxicGasRisk
severity: moderate
primaryHazards: [object Object]
description: Carbon monoxide generation detected - moderate toxicity risk
mitigation: Half-face or full-face respirator with organic vapor/particulate cartridges, adequate ventilation
VentilationRequirements
exhaustVelocityMS: 0.5
filtrationType: HEPA
minimumAirChangesPerHour: 10
rationale: Standard industrial ventilation (10 ACH) for particulate control
VisibilityHazard
severity: moderate
description: Moderate visibility reduction (40-60%), significant particulate haze
source: Respirable fraction: 0.70 (70% of particles <10μm)
mitigation: Ensure clear sight lines, use source extraction, maintain awareness of surroundings
relatedField: particulate_generation.respirable_fraction
ThermalProperties: AblationThreshold
pulseDuration100Ns: 4.5
pulseDuration10Ns: 3.2
wavelength1064Nm: 2.8
DecompositionTemperature
1800
HeatAffectedZoneDepth
45
MeltingPoint
1500
SpecificHeat
650
ThermalConductivity
8.5
ThermalDiffusivity
1.6
VaporizationTemperature
2800

Thermal Spray Coating Dataset

Download Thermal Spray Coating properties, specifications, and parameters in machine-readable formats

Variables

Safety Data

Characteristics

References

Formats

Download Format

View all Thermal-damage datasets

License: Creative Commons BY 4.0 • Free to use with attribution •Learn more

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