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Applications of Green Technology in the Manufacture of Turbine Blades . Karl S. Ryder Scionix Laboratory, Department of Chemistry, University of Leicester, Leicester, LE1 7RH, UK [email protected]. Contents. What is an ionic liquid Eutectic-based ionic liquids and how to make them - PowerPoint PPT Presentation
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Applications of Green Technology in the Manufacture of Turbine Blades
Karl S. Ryder
Scionix Laboratory,Department of Chemistry,
University of Leicester,Leicester, LE1 7RH,
UK
Contents
• What is an ionic liquid
• Eutectic-based ionic liquids and how to make them
• Applications Immersion Ag for PCB's
Cr plating
Al Plating
Battery applications
• Electro polishing
• RS Industrial Fellowship scheme
• Results (RR3010 blades), XPS
• Closing remarks
Ionic liquids: definition
Ionic material that melts below 100 ºC
• Unusual solvent properties
• Very low / negligible vapour pressure - do not evaporate
• Most liquids thermally stable >200 ºC
• Immiscible with many organic solvents
• Some have wide potential windows
• Large and unsymmetrical ions -> low lattice energy and
hence low melting point
Historical perspective
1914 EtNH3+NO3
-
1980’s Pyridinium eutectic with AlCl3 researched for Al deposition and Al batteries
1990’s Prevalence of imidazolium based cations
2000’s Environmentally more benign ionic liquids
Liquid preparation
10 ILs have been produced in over 200 kg batches One IL made on the tonne scale (for electropolishing)
• Just mix two components (often r.t. solids) to make liquid!
• Endothermic reaction, entropy driven
Electropolishing
Electrochemical dissolution: ChCl / EG liquid High current efficiency Low toxicity No strong acids Comparable finish
Electropolishing
Pilot plant Functional process line Pre treatment Process, 50 L IL Rinse
Works very well for 300 series stainless steels and high value performance alloys, Ni / Co, Ti etc.
Electropolishing
Better surface finish (market)Non-corrosive (social)Benign liquid – ChCl/glycol (social)Improved current efficiency (>80%) (economic)Less gas evolution (environmental)Metal recoverable (environmental)
SS or Ti / IrO2 CathodesTi JigsStandard pump / tank fittingsLess gassingBetter current efficiency
Electropolishing
Royal Society Industry Fellowship (KSR)Started July 2010:
• Explore electropolishing of superalloys with IL processes• Study composition of alloy • Determine etch rate• Explore removal of scale (effect on surface melting)• Explore removal of casting shell
Electropolishing
Strategy:
• Polish metal• Vary conditions• Characterise surface• Heat treat
Electropolishing; surface characterisation
Electropolish
Sample 1 (pale)
Electrolytic polishing in IL removes virtually all residual shell.
First results suggest alloy composition is not effected by etch
Surface roughness greatly reduced
Ni(3p)
Electropolishing
Partially immersed , polished blade (RR3010)20 mins process time.
Electropolishing
Fully immersed , polished blade (RR3010)60 mins, total process time.Eapp = 5.8 V
Electropolishing
Fully immersed , polished blade (RR3010)60 mins, total process time.Eapp = 5.8 V
Some trapped shell loosened!
Electropolishing: recycling
Spent polishing liquid from the electropolishing process can be recycled and reused:
(a) Spent liquid(b) Equal volume of water added
SettlementFiltrationHeating (remove water)
(c) Recylced liquid
Conclusions
Electropolishing of superalloy turbine blades in DES type (choline chloride based) ionic liquids:
• Effective in removing Ni-based surface scale • Effective in removing residual shell• Homogeneous dissolution of metal• Isotropic etching (semi-quantitative XPS)• Reducing surface roughness• Softening / loosening trapped shell
Visualising grain structure possible prior to heat treatment possible by electrolytic etch. This has the potential to save process time and reduce production costs.
Hard back, 338 pagesISBN-10: 3-527-31565-9
ISBN-13: 978-3-527-31565-9 Wiley-VCH, Weinheim