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Research Fellows Directory

Karl Ryder

Dr Karl Ryder

Research Fellow


University of Leicester

Research summary

The purpose of this research proposal is to develop a step change for the processing of super alloys. A novel process for electropolishing aerospace castings using ionic liquids is being developed. Specifically this project is (i) exploring the application of novel liquids for electrochemical removal of silicate and metal containing scale from turbine blade castings, (ii) seeking to understand how scale forms during solidification on single crystal turbine blade castings. Electropolishing is an electrolytic dissolution process that removes small-scale features from a metallic surface leaving a bright and smooth morphology. Conventional (commercial) electropolishing in aqueous electrolytes requires a cocktail of strong inorganic acids that are toxic and unpleasant to work with. In addition these electropolishing electrolytes do not work for Ni based super alloys; anisotropic etching causes pitting and increased surface roughness. Current technology involves manual machining of each intricate piece and is both time and labour intensive. In contrast, the Leicester Ionic Liquids group has previously shown that ionic liquid electrolytes are effective alternatives to aqueous acids in electropolishing stainless steels and Ni / Co alloys. Continuing trials have also shown that electropolishing of high performance super alloy aerospace castings can remove casting scale & reduce surface roughness. We seek to understand and quantify the compositional and morphological changes to the alloy that occur during the polishing process. These liquids are much easier to work with, less toxic, contain no strong acids and operate at much higher energy efficiency. The ionic liquids used in this project are based on binary mixtures of choline chloride & one of a number of possible hydrogen bond donor such as ethylene glycol, urea or carboxylic acids. These components are widely available, relatively inexpensive & require no additional registration for commercial use.

Grants awarded

Surface Treatment of Super Alloy Castings With Ionic Liquid Technologies

Scheme: Industry Fellowship

Dates: Jun 2010 - Nov 2012

Value: £56,374

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