Emerald Group Publishing Limited
Copyright © 2008, Emerald Group Publishing Limited
Zinc alloy coatings offer high performance
Article Type: New materials and equipment From: Anti-Corrosion Methods and Materials, Volume 55, Issue 2.
MacDermid has introduced the MacuGuard LM coating system to offer OEM's, engineers and surface finishers a bulk production, non embrittling, high-performance coating system suitable for small components. Not only does the coating provide excellent sacrificial corrosion protection, but it also provides the most advanced coating available for contact corrosion with aluminum alloys.
MacuGuard LM coatings are based on a unique zinc aluminium alloy and offers performance benefits which, said MacDermid, no other coating can deliver. MacuGuard LM stands for non embrittling high corrosion resistant coatings with excellent electrical connectivity, predictable friction, zero head and thread fill and EoLVD compliance. The ability to successfully process complex geometries, including fastener sizes below M6, makes MacuGuard LM the perfect high-performance coatings.
To meet the market requirements, two coatings have been developed:
1 The MacuGuard LM mechanical plating processes incorporates a simple additive system, which is capable of producing MacuGuard LM 90, a single layer alloy deposit.
2 MacuGuard LM Duplex, a two layered deposit.
The MacuGuard LM 90 finish is based on a “true” zinc-aluminium alloy which contains 8-11 percent aluminium and is particularly suitable in reducing galvanic induced corrosion between steel fasteners and aluminium components, said MacDermid. In various corrosion investigations according DIN, ASTM and OEM specifications, this finish proved to give the highest corrosion performance. The MacuGuard LM Duplex finish is based on a two layered deposit based on a zinc layer and a second zinc aluminium alloy layer. In various corrosion investigations according DIN, ASTM and OEM specifications, this finish proved to give highest corrosion performance and very good prevention of galvanic corrosion in contact with aluminium.
MacuGuard LM Duplex delivers performance at the competitive costs and the coating is ideal to replace high- performance finishes like dip spin coatings. Coating components may be used within a shot time of processing without fear of embrittlement failure. No subsequent heating or de-embrittlement procedures are required before use. This means MacuGuard LM is the most energy efficient process available for high-performance zinc-based coatings. It conforms to all chrome free tests required of the automotive OEM's. It is fully compliant with EoLVD, WEEE and RoHSO legislation. MacuGuard LM is a solvent free process therefore requires no special extraction, venting or fume scrubbing systems. It is not regulated for air emissions and dose not liberate any VOC's MacuGuard LM is a novel mechanically deposited true alloy coating. The 100 percent metal film provides exceptional abrasion resistance as well as other performance characteristics. As with most zinc-based pure metallic coatings, it offers excellent sacrificial corrosion protection. Top coats can be easily applied to provide a further variety of surface enhancing properties like insulation, color, controlled torque- tension and low coefficient of friction. The coating also readily accepts thread “patching” of all types.
In contact with aluminum, MacuGuard LM offers some of the best corrosion and cyclic corrosion testing of any coating available today. This unique feature is the result of an alloy specifically engineered to provide contact corrosion with light metals.
Features are as follows:
Free form hydrogen embrittlement.
Excellent corrosion performance proven according several test specifications.
Zero thread or head fill.
ELV-, WEEE- and RoHS-compliant.
No oven cure required.
More information is available from the web site located at: www.macdermid.com