Surface Engineering Techniques

Surface Engineering Techniques

Thermal Spraying

• Thermal Spray Center Finland (TSCF)

Welding and Laser Cladding

Thin Film Technologies

Surface Modifications

Thermal Spray Equipment

Traditional Thermal Spray Equipment

• Flame Spray

• Electric Arc Spray

• Plasma Spray

Advanced Thermal Spray Equipment

• High-Velocity Flame Spray (HVOF and HVAF)

• Suspension- and Precursor-HVOF

• Low-Pressure, Medium-Pressure and High-Pressure Cold Spray (CS)

• Laser-Assisted Cold Spray

Thermal Spray Center Finland (TSCF), www.tscf.fi

Thermal Spray Processes

Process Temp.

(°C)*

Particle

velocity

(m/s)

Bond

strength

(MPa)**

Oxides

(%)***

Porosity

(%)

Spray

rate

(kg/h)

Relative

costs

Typical

thickness

(mm)

Flame 3000 40 8 10-15 10-15 2-6 1 0.1-15

Arc 4000 100 12 10-20 10 10-25 2 0.1-50

HVOF 3000 800 >70 1-5 1-2 2-8 3 0.1-2

Det. 4000 800 >70 1-5 1-2 0.5-2 4 0.05-0.3

APS 12000 200-400 10…>70 1-5 1-5 2-10 4 0.1-1

VPS 12000 400-600 >70 0 <0.5 2-6 5 0.1-1

Cold <1000 550-1200 20…>70 0 <0.5 6-8 3 0.1-50

*Temperature of heat source, **Depends on materials, ***Amount of oxides in metallic coatings

Flame Spray Equipment

• Sulzer Metco 6P-II (powder, suspension)

• Castolin DS 8000 (powder)

• Sulzer Metco 12E (wire)

• Saint Gobain MasterJet (wire, rod, flexicord)

• TeroDyn (for polymers)

Flame spraying (FS)

• Mixture of fuel gas (acetylene, propane, hydrogen) and oxygen burns and melts the feedstock material molten particles are sprayed to the surface

• Materials: metals, metal alloys, ceramics, polymers

• The cheapest thermal spray method

• Applications e.g., corrosion protection (Al and Zn),

bond layers, icephobic surfaces

Electric Arc Spray Equipment

• Oerlikon Metco SmartArc

Electric arc spraying (Arc)

• Based on the use of electric arc between two metallic wires fed into the gun arc melts metallic wires and melted particles flow to the sprayed surface with process gas

• Arc spraying is more effective method than flame spraying

• Materials: Metals and metal alloys

• Applications e.g., wear resistant metal alloy coatings, corrosion protection of large areas (Al, Zn)

Plasma Spray Equipment• Oerlikon Metco F4

Power 55 kW

• Saint Gobain ProPlasma

Power 65 kW, powder feeding rate up to 9 kg/h

Atmospheric plasma spraying (APS, PS)

• Strong electric arc is generated between Cu anode (+) and W cathode (-) ionizes the flowing process gases (argon, helium, hydrogen, nitrogen) to the plasma state

• Feedstock material is injected to the plasma jet melting the particles and propelling them onto the workpiece surface

• Materials: ceramics, hardmetals, metals

• Applications: e.g., wear and corrosion protection, thermal insulation 200 µm

HVOF Spray Equipment

• Oerlikon Metco DJ Standard (propane), DJ-1000 (propane), DJ-2600 (hydrogen) and DJ-2700 (propane, ethene)

• GTV Top Gun (hydrogen, ethene)

• Miller HV-2000 (hydrogen, ethane)

• S-HVOF (suspension)

High-Velocity Oxygen-Fuel spraying (HVOF)

• Based on continuous burning of fuel gas and oxygen in the combustion chamber (in the gun) under high pressure generates high speed gas flow in which powder is fed with carrier gas

• Mostly used for hardmetals and metal

alloy coating production (e.g., WC-Co),

wear and corrosion protection

HVAF Spray Equipment

• Uniquecoat Technologies LLC M3 spray gun

• Propane/air

• Kermetico HVAF AK7 spray gun

• Propane/air

High-Velocity Air-Fuel Spraying (HVAF)

• Similar process than HVOF but uses

compressed air instead of oxygen

• Process temperature is lower and particle

velocity higher than in HVOF

• Materials: hardmetals, metals and metal alloys

• High-performance coatings e.g.,

for corrosion and wear protection

200 µm

Process M3 (HVAF)DJ2700

(HVOF)

Power ~300 kW ~100 kW

Powder

feeding<400-500 g/min <100 g/min

Cold Spray Equipment• PlasmaGiken PCS-100 HPCS system

• Process gas: N2 or He (70 bar, 1100°C)

• Pure metals and metal alloys

• CGT Kinetiks 3000 MPCS system

• Process gas: N2 or He (30 bar, 550°C)

• DYMET 403K LPCS system

• Process gas: compressed air (9 bar, 650°C)

• Metal-ceramic powder mixtures

• Laser-Assisted Cold Spray System (COLA)

Cold spraying (CS)

• High velocity, high kinetic energy particles impact, deform and adhere to the sprayed surface, forming the coating

• No melting, no oxidation (dense and high quality coatings)

• Application fields: corrosion protection, electrical and thermal conductivity, repair, additive manufacturing

Contacts

Prof. Petri Vuoristo

petri.vuoristo@tuni.fi, +358 40 849 0044

Dr. Tech. Heli Koivuluoto

heli.koivuluoto@tuni.fi, +358 40 849 0188