The benefits of nickel-free phosphating 22 February 2017

Nickel-free KeyKote™ phosphating technologies cover a multitude of applications for improving corrosion protection, bonding and wear reduction. These benefits are realised across a number of industries including automotive, aerospace, oil and gas, construction, and metalworking.

The advantages of nickel-free phosphating are in the area of industrial wastewater treatment and corresponding operator safety in product handling. The innovative iron management in KeyKote™ products limits the iron content of the bath solution and therefore reduces new make-ups and reduces bath maintenance.

When the primary requirement is for resistance to red rust after neutral salt spray exposure, heavy weight zinc or manganese phosphate provides the base coating. Combined with corrosion protective oil they can reach in excess of 72 hours without red rust in neutral salt spray testing. Crystalline manganese phosphate (coating weights up to 25g/m2) absorb oil and other lubricants exceptionally well. They provide exceptional wear resistance and running-in of sliding parts in power train and transmission applications.

If a microcrystalline phosphate is required, then zinc calcium phosphate is recommended. These are supplemented by a corrosion inhibitor/ coefficient of friction modifier. Light to medium weight zinc phosphate coatings provide a corrosion resistant base and offer excellent adhesion for subsequent paint coatings.
With the appropriate friction modifier, phosphate coatings will return these coefficient of friction values:
• Heavyweight zinc phosphate is typically within the range of 0.12 – 0.30
• Microcrystalline phosphate is within the range 0.08 - 0.16

The properties of the coating in terms of weight, thickness and topography can be adjusted to meet appropriate specifications. All products nickel-free KeyKote products give economical low consumption, cost-effective working temperature and reduced sludge formation.

Phosphating for fasteners by applying KeyKote under the new ZinKlad 72 programme
One of the main markets for the MacDermid Enthone Metallurgy product group is the automotive industry, especially the growing need for phosphating of fasteners.

The ZinKlad program, proven globally for over 10 years, is in a unique position to add value to this sector by using the existing applicator base and previous knowledge of the existing supply chain. The opportunity to both specify and implement the new ZinKlad 72 will assist the automotive OEM's by reducing their audit requirements.

KeyKote attributes include consistency in performance, global availability, control of incoming material quality and meeting the desired specification. Coupled with the process optimisation of the ZinKlad programme, this new performance level matches the requirements of the automotive supply chain.

Claire Aldridge Deputy Editor t: +44 (0) 1727 743 889

Having spent a decade in the fastener industry experiencing every facet – from steel mills, fastener manufacturers, wholesalers, distributors, as well as machinery builders and plating + coating companies, Claire has developed an in-depth knowledge of all things fasteners.

Alongside visiting numerous companies, exhibitions and conferences around the world, Claire has also interviewed high profile figures – focusing on key topics impacting the sector and making sure readers stay up to date with the latest developments within the industry.