Appliance Design - November 2007 - (Page 48)

METALS & METAL PARTS Lightweights Get Tough Power Supply Plasma Discharge Mg Magnesium components on this bicycle were treated with Keronite for corrosion resistance and to provide good adhesion for decorative topcoat. Electrolyte Fig. 1. Illustration of the Keronite plasma electrolytic oxidation process. Treatment technology hardens surface of light alloys. by anne wilde Anne Wilde is director of marketing, Keronite PLC, Cambridge, U.K. 48 applianceDESIGN November 2007 n recent years there has been growing interest in using lighter weight materials across a broad range of applications. This is particularly true of the aerospace and automotive industries, where there is increasing environmental pressure being brought to bear on manufacturers to reduce emissions. But, in fact, many other applications, including portable devices, can benefit from a switch to lighter materials given the appropriate surface characteristics. Light alloys such as aluminum and magnesium present attractive alternatives to heavy steel or ceramic in many environments, but their use has traditionally been limited to the less demanding applications where corrosion and wear are not an issue. However, many design engineers are starting to realize that innovative surface treatment technologies can create new possibilities for using light alloys in a variety of industries and applications. One such treatment is the Keronite I Plasma Electrolytic Oxidation (PEO) process that allows designers to use light alloys in places not previously possible in the past with conventional surface treatment systems. With hardness measuring up to 2000 HV (Vickers), Keronite on aluminum is harder and considerably more wear resistant than steel. Likewise, Keronite on AZ91D magnesium alloy is able to resist corrosion in a salt spray environment for as much as 2,000 hours, making magnesium a much more attractive material than ever before. The process The patented, chrome-free Keronite PEO process transforms the surface of light alloys such as aluminum and magnesium into a complex ceramic composite by anodic conversion under plasma discharge conditions in a non-toxic electrolyte solution. (See Fig. 1.) The Keronite process resembles anodizing in that electricity is passed through a bath of electrolyte, but the technology is significantly www.applianceDESIGN.com http://www.appliancedesign.com

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Appliance Design - November 2007 Contents Editorial Shipments/Forecasts News Watch Today’s LEDs are Brighter and More Colorful than Previous Versions, Allowing Designers More Opportunities to Improve and Differentiate Their Products. When Converting from CCFL to LED Backlights in LCD Panels, New Driving Methods are Needed. Electrowetting Technology Allows Displays to be Designed in an Extensive Range of Colors. Noise Problems are Not Always Easy to Find or Fix, but Acoustic Labs Can Help Designers Ferret Out the “Good” Noise from the “Bad.” A New Sanitization Protocol for Clothes Washers Combines the Best of Three Well-Established Provisions to Ensure Efficiency, Quality and Safety. Stricter EMC Requirements Raise the Bar for Appliances with Electronic Controls and Require Testing to New Levels. Despite Added Cost and Complexity, Gas-Modulating Systems have Migrated from Large-Scale Boiler Applications to Smaller Residential and Commercial Furnaces and Appliances. A New Treatment Technology Hardens the Surface of Light Alloys such as Aluminum and Magnesium and Expands Their Potential Applications. DesignMart Advertiser’s Index Association Report: AHAM

Appliance Design - November 2007

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