Functional Coatings on Steel in the Built Environment -Current and Future Technologies
1. Functional Coatings on Steel in the Built Environment
-Current and Future Technologies
Dr Sanjay Ghosh
Research Officer
Sanjayghosh.uk@gmail.com
Bangor University
2. Functional coating is all about material that do things
Application of Functional Coating on Steel
Energy efficiency
1. Photovoltaic electricity generation
2. Solar heating
3. Electroluminescent display
Healthcare and safety
1. Intumescent coating for fire protection
2. Anti-microbial coating for health
Key area :
Intumescent Coating on Exposed Structural Steelwork
Festival Place, Basingstoke and City Point, London (Leigh’s Paints)1. Corrosion resistance paint
Weather Protection
3. Solar Cell Fabrication on Low Cost Rough Steel Surface
0.3mm
400nm
200nm
2.5-3mm
400nm
500nm
Organic photovoltaic (OPV) Amorphous silicon solar cell (a-Si:H)
Functional coating: SU8 compatible for OPV,
Sol-gel, SiOx compatible for a-Si:H & OPV
PCE = 3%
PCE = 6%
Sol. Energy Mater. Sol. Cell 2016, 157, 305 Sol. Energy 2016, 124, 216
4. Characterisation of Steel + Functional coating (IL) for PV
Leakage current
For solar applications : Ra~0.03μm, Rz~0.3μm
Steel (Roughness high) Steel +IL (Roughness low)
Functional coating
Steel +
IL
Electrical
insulation
Diffusion
barrier
Mechanical &
Thermal
stability
Surface
leveling
Pencil method
4
5. Sol-gel (SiOx) Formulation and Development
SiOx mix = Tetraethylorthosilicate (TEOS) + Methyltriethoxysilane (MTES) + Polyethylene Glycole (PEG) + HNO3 + H2O
SiOx coating is compatible with both vacuum and non vacuum deposition method
Spray coat, bar coat, PVD deposition
Temperature of curing = 100 -300 oC for PV application
6. SU8 (IL) Formulation and Development
Gamma Butyrolactone) 22-60%
Mixed Triarylsulfonium/ Hexafluoroantimonate Salt 1-2%
Propylene Carbonate
Epoxy Resin (Formaldehyde, polymer with 2-
(chloromethyl)oxirane and 4,4'-
(1-methylethylidene)bis[phenol])
35-75%
Volume
1-5%
Substrate (steel)
cleaning
coat (K-bar)
Soft bake,
125 -150 oC,
10 min
Develop, 15 min
Hard bake,
230-250 oC,
15 min
SU8 Mix
Processing steps
Surface coverage = 70 g/m2, 60 um thickness film, Bar coat
7. Economic Viability of Low Carbon Steel + IL as substrate for PV
Cost Steel + ILs should be below 0.175 €/Wp for PV
Annu. Rev. Mater. Res. 2011, 41, 297Sol. Energy 2016, 124, 216
8. Solar Heater
Ren. Sus. Energy Rev. 2016, 58, 574
Evacuated-tube Solar Collector (Riomay)
Evacuated-tube Solar Collector (Espionoza Energy)
Fe2O3/Stainless Steel at Different temperature
9. High Temperature Solar Absorber on Steel
Author Coat Technique Absorptance
α
Emittance
ε
Remarks
Ambriosini et al.
2010
FeCo2O4
NiCo2O4
Spin coat 0.88
0.82
0.59
0.46
Thermal stability above 600 oC
Liu et al.
2012
NbTiON/SiON Magnetron
sputtering
0.95 0.07 Thermal stability above 500 oC
Valleti et al.
2014
TiAlCrN/TiAlN/AlSiN Cathodic arc
PVD
0.91 0.07 Degrade at high temperature
Cespedes et al.
2014
Mo-Si3N4 Magnetron
sputtering
0.93 0.02 Potential to be used for CSP
Liu et al.
2014
Cr-Al-O Cathodic arc
ion plating
0.92 0.21 Suitable for collector at higher
temperature
Liu et al.
2017
TiC-WC
TiC-WC/Al2O3
Magnetron
sputtering
0.78
0.92
0.11
0.11
Stable up to 500 oC
Wu et al.
2017
Fe2O3 Thermal
oxidation
0.91 0.18 Stable up to 900 oC
10. Future Trend of Functional Coatings
Example: Acronal® Pro 7600 - latest innovation for corrosion protection
for industrial metal coatings presented at the European Coatings Show
this month.
Conventional to sustainable technology-water based environmental friendly
With VOC regulations at 50 g/L and below,
Self healing, self cleaning properties, sensing abilities, etc.
April 2017, Germany
Chem. Mater., 2010, 22 , 4406
Anti-corrosion paint (BASF)
Talk about the intermediate coating as
functional material.
Its characterisation and development
And test strategy
Dielectric property, insulation , robustness, and stability
The cost for ‘rough’ substrate can be 30-40% reduced as compared to high roughness grade.
For solar applications the surface roughness of substrates should be generally very low: Ra~0.03μm, Rt~0.3μm
Al (100 nm) deposited by thermal evaporation using Edward thermal evaporator.
Talk about the intermediate coating as
functional material.
Its characterisation and development
And test strategy
Dielectric property, insulation , robustness, and stability
Talk about the intermediate coating as
functional material.
Its characterisation and development
And test strategy
Dielectric property, insulation , robustness, and stability
Talk about the intermediate coating as
functional material.
Its characterisation and development
And test strategy
Dielectric property, insulation , robustness, and stability
10% efficiency module
Talk about the intermediate coating as
functional material.
Its characterisation and development
And test strategy
Dielectric property, insulation , robustness, and stability
Talk about the intermediate coating as
functional material.
Its characterisation and development
And test strategy
Dielectric property, insulation , robustness, and stability
With VOC regulations at 50 g/L and below, formulators are looking for ways to achieve this goal while maintaining performance properties
Self healing, self cleaning properties, sensing abilities, etc., will require new material chemistries and processes that will require extensive vetting of performance and durability through comprehensive testing
Talk about the intermediate coating as
functional material.
Its characterisation and development
And test strategy
Dielectric property, insulation , robustness, and stability
Talk about the intermediate coating as
functional material.
Its characterisation and development
And test strategy
Dielectric property, insulation , robustness, and stability
