Zinc-Nickel Abrasion and Resistant Coating

Abstract

zinc nickel platingZinc-nickel finishes with a 12-15 % by weight nickel content are widely used in the automotive, aerospace and electronics industries. In automotive applications the coating is used in both interior and exterior applications.

Automotive engineers choose zinc-nickel due to its excellent corrosion and abrasion resistance. This results in the coating retaining its corrosion protection even after handling and assembly operations. An example of this is applications such as door strikers and latches where abrasion resistance is the most important factor.

ZinKlad 1000, the highest level of performance in the MacDermid ZinKlad range of finishes, uses zinc-nickel as the base metallic coating.

Summary

Electroplated zinc-nickel coatings demonstrate the following features:

  • Exceptional corrosion resistance for relatively thin coatings
  • Hard coating, good for mechanical resistance properties
  • Suitable for electronic applications such as grounding screws
  • Galvanic compatibility with aluminum
  • Lubricated to modify friction properties

The specific properties of zinc-nickel finishes of corrosion and abrasion resistance, conductivity and adjustable friction make these coatings successful in many applications. Extensively used in the automotive industry, zinc-nickel coatings are also used in aerospace and electronics applications.

 

In Conclusion

MacDermid continue the development of zinc-nickel coatings to meet today’s industry requirements. Recent technology improvements include increasing electrolyte efficiencies, improving the aesthetics of the zinc-nickel coating and retention of corrosion resistance after post-plate deformation.

Additionally, development work includes cobalt-free trivalent passivation systems and lubricants to deliver friction properties for specific applications such as fasteners used in multiple tighten / untighten situations.

Read more

http://industrial.macdermid.com/ebooks/zinc-nickel-2013/

Annual German ZinKlad Meeting 2013

ZinKlad logo

25th April 2013 was the date for the annual meeting of the German ZinKlad “club“. This annual gathering facilitates open discussion between all the German ZinKlad Approved Platers and the MacDermid sales, technical and OEM teams.

German ZinKlad Applicators

German ZinKlad Applicators

This year, there was a special surprise as MacDermid Sales Director, Michael Barz, handed out engraved metallic ZAP certificates to mark more than 10 years success of the ZinKlad program in Germany!

The meeting started by Managing Director, Thomas Dyllus, explaining the structure and sales growth of MacDermid GmbH. He also outlined the strategy of innovation and collaboration with the major global automotive manufactures. Both key points which benefit the platers themselves by generating new business potential and technologies which can fulfill these opportunities.

The discussion then turned to the global perspective. European Marketing Manager Mr. Mark Baker highlighted some key successes from the past year in the ZinKlad program which included:

• The rise to some 70 ZAP worldwide including 30 in Europe
• Approval by GM for ZinKlad 1000
• John Deere entering the approval process for ZinKlad 250
• New ZAPs in the emerging India and Thailand markets
• Ford approval of ZinKlad 1000 (S450) and changes to the S437 program which exclusively calls out ZinKlad 96 and 250

Finally this discussion was finished by outlining the ZinKlad vision for the next decade, continued global availability, compliance and performance improvement.

OEM Key Account Managers Otfried Bertram (VW) and Rainer Lakner (BMW/Daimler) then took the opportunity to update the delegates with the latest data from the German automotive industry. This included production, sales and longer term strategies.
They also dedicated time to the success of the MacDermid zinc-nickel Enviralloy NiFlex 12 coated fluid transfer tubes which are post plate deformed. Along with the synergistic TriPass ELV 3100 and HydroKlad Si, this coating is fully approved to VW TL244. As the coating is able to meet the performance specification after post plate deformation, this represents a major cost saving for the automotive
tube supply chain.

The agenda then turned to what tomorrow holds in store for the platers of sacrificial coatings. Christian Zimmermann, Global Anti-corrosion Junior Product Manager introduced the REACH legislation, and in particular how it relates to cobalt containing trivalent passivates. As this (cobalt) material may be prohibited in future, MacDermid already have cobalt free passivation systems working in the field. The new 7000 range of TriPass trivalent chromium passivates can be applied to both zinc and zinc alloys and operate in both rack and barrel.

A new zinc-nickel was then introduced, Enviralloy Ni-Speed. A bright zinc-nickel for rack plating which is designed to overcome deficiencies with current processes, namely brightness and plating speed. By adopting this new process platers can give a better appearance to their zinc-nickel plated parts and produce them in a shorter plating time, thus increasing production capacity.

ZinKlad certificate

ZinKlad metal certificate

The meeting concluded with an open discussion by the Platers before being presented with the new engraved plaques. Everyone agreed that the meeting had added value to their current perspective of the German automotive requirements. They all look forward to the next meeting in 2014, and of course hanging the new plaques on their reception walls!For further information, please contact Michael Barz – mbarz@macdermid.com

http://www.zinklad.com

Coatings for high tensile fasteners

Mechanical plating

High tensile fasteners are mechanically plated

When coating performance is considered, hours to white or red rust are the normal criteria. However with high tensile fasteners, threaded or unthreaded, being free of hydrogen embrittlement is an equally important factor. For this reason components such as rivets and safety critical fasteners are zinc coated using a mechanically applied process rather than traditional electroplate. This process also offers advantages in bulk application against organic dip spin that even the smallest fastener can be treated without head / recess fill or parts sticking together.

Mechanical plating

 In the mechanical plating process the zinc is present as fine dust. It is deposited by a cold welding process. Impact energy is transferred from a rotating open ended barrel through glass beads to the zinc dust. This impacts the zinc against the steel substrate. The resulting deposit provides corrosion protection to the articles without introducing hydrogen embrittlement into the part.

The main features of the mechanical zinc process can be summarised as:

• No risk of Hydrogen Embrittlement
• Excellent corrosion protection
• Choice of zinc, zinc aluminium or zinc tin alloys
• Automated bulk process
• Room temperature, cold welding batch by batch capability
• Non-electrolytic process
• Thicknesses can range from 8µm to over 75µm

The benefits to the specifier are reliability, security and value.

Reliability

 The consistency of mechanical plating can be demonstrated by the replication in processing and the resultant coating. Additionally mechanical plating is specified by automotive manufacturers within the ZinKlad approved applicator program.

Plating process

The plating process is defined by process steps which are always the same. The only change, batch to batch, is the amount of material added (i.e. zinc dust). These quantities are correlated to the surface area being coated and the thickness required. These factors mean that the results are reproducible time and time again.

Coating performance

250 hours neutral salt spray

Protects for more than 250 hours in neutral salt spray

This reproducibility means a predictable coating is produced. Mechanical zinc plating, specified for over 30 years now by many major automotive manufacturers, delivers corrosion resistance similar to electroplated zinc for the same given zinc thickness. This means that an 8µm coating will resist more than 250 hours to red rust. Therefore exceeding requirements for:

• Non threaded fasteners such as rivets for joining metal
• Threaded fasteners used in safety critical assemblies such as seat belt mountings

Applicator program

Automotive companies often specify their surface finishing within an applicator program. This program aids coating reliability through a common audited standard. This helps to ensure the same coating performance throughout the applicator base, regardless of geographical applicator location.

Security

A common feature of the 2 component types mentioned above is that both are constructed from high tensile steel. It is generally accepted that steels having a hardness above Rockwell C-40 are susceptible to hydrogen embrittlement.

One of the issues of hydrogen embrittlement, is that the higher-strength steels which are used to bear high loads are the very steels which can fail from hydrogen embrittlement at loads much less than their design load. The role which the hydrogen plays in the failure mechanism includes factors such as internal pressure from gas formation, formation of metal hydrides, stress concentration due to interactions with metal imperfections, and micropore or microcrack formation.

This now returns to the need for a coating free of hydrogen embrittlement to prevent failure in use. For the components mentioned above, hydrogen embrittlement could mean:

• A Rivet which fails to pierce and join metal layers
• A safety critical bolt which fails under intense load

Value

Rivets in pile

High tensile self piercing rivets are also plated with mechical zinc alloys

Mechanical plating is an economical method of producing zinc coatings on high tensile steels due to:• No need for the hydrogen de-embrittlement process – Electroplated zinc coatings need to be de-embrittled within 2 hours of plating at 200ºC for 4 – 24 hours (dependant on part geometry and packing density). Additionally any passivation must be applied following this baking operation. These steps add cost due to increased process stages and energy consumption.

 • Automated equipment for bulk processing – Mechanical plating is applied in bulk processing, often in automated equipment. This increases productivity due to high loading and reduces operator costs.

• Coating uniformity and freedom from parts ‘sticking’ – These factors can reduce costs when compared to organic dip spin finishes, especially on rivets or fasteners with recessed heads.

• Low environmental impact – Finally the mechanical process results in very little waste material. This is because the majority of the material added during the plating operation is consumed to produce the final deposit.

 Summary

Mechanical plating, extensively specified for over 30 years now, is considered one of the 3 primary coating systems for threaded and non-threaded fasteners. Primarily specified to provide sacrificial protection to high tensile steel components, it offers advantages in its ability to treat small and recessed parts without sticking or filling issues. The coating is uniform and consistent and can be specified for both joining and safety critical applications. Finally the bulk nature and low waste make mechanically plated sacrificial coatings extremely cost effective.

ZinKlad Welcomes…Retsacoat – Portugal

Congratulations to the Retsacoat team seen receiving there new ZinKlad certificate from Daniel Algar and Belina Raposo MacDermid Portugal.

RETSACOATTratamentos de Superficies Metálicas Lda, leading company in thermal and anti-corrosive treatments, started its activity in 2001. Retsacoat is a member of the Pecol business group. This partnership has been essential for the development of our current surface treatments.

To View this article on Retsacoat and ZinKlad in Spanish / online ebook, follow link  

Retsacoat started as lamellar (dip spin) zinc applicators inPortugal. In 2006, as a result of the Cr VI restriction in surface treatments, we became approved for the application of chromium-free lamellar zinc processes.

These thin film anti-corrosive treatments are the best alternative for a great number of parts. For example, the absence of chemical pickling eliminates the risk of hydrogen embrittlement. The thin thickness and integrated lubrication, allows a perfect assembly, even with small metric screws. Lubrication, an increasingly important issue, allows us to meet these market demands.

Recently we completed our portfolio of electrolytic treatments with the implementation of a fully automatic line for zinc, zinc nickel and zinc iron.

The support and collaboration of MacDermid has been fundamental. From the beginning of 2012, we are the first company in Portugal certified with the process ZinKlad 250 and ZinKlad 1000. With these new processes, we offer our customers the best solution in electrolytic finishing processes.

For lubrication of the ZinKlad finishes we offer both Torque ‘n’ Tension 11, and Torque ‘n’ Tension 15. Collectively these provide the optimal controlling the coefficient of friction characteristics.

Strategy

Retsacoat have always been a pioneer in the latest equipment and finishing technology. We have implemented fully automatic lines that allow us to deliver finishes of high quality and consistency, at very competitive prices and with a reduced time for deliveries.

Quality

Quality is always a high priority for us. All surface and thermal treatments require a perfect control, both of the processes and finished product. In our in-house laboratories we carry out the most demanding tests including hardness testing, deposit observations by microscope, neutral spray salt, measurements of thickness by X-ray and also coefficients of friction.

Environment

Our concern for the environment has always been an essential part of the process development. Effluent gases such as liquid heat and finishing treatments are controlled by our in-house treatment equipment.

RETSACOAT – the solution for your mechanical parts.  http://www.retsacoat.pt/

ZinKlad…Supporting the highest quality standards

The ZinKlad™ quality assurance programme is taking on the challenges for high performance automotive coatings of the future. Introduced 10 years ago, ZinKlad has enabled many global OEM’s to specify higher standards than they achieved with previous, hexavalent chromium based coatings.

Logo for ZinKlad

ZinKlad for high performance ELV compliant coating

In the new globalising world, OEM’s must change and adapt, and ZinKlad continues to respond to these requirements worldwide. Today ZinKlad offers high performance coatings, proven consistent quality and a global network of approved applicators.

Of course, compliance with legislation, such as ELV & RoHS, and predictable torque-tension performance continue to be essential requirements. ZinKlad continues to deliver on all of these needs.

So as we move into the future, you can be sure that the high corrosion resistant coatings, freedom from proscribed materials and consistent friction control, will remain today as true as when ZinKlad was first specified.

http://www.industrial.macdermid.com/

 

Zinc plated finishes for ZinKlad

ZinKlad Finishes

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