Steel in Corrosion and Wear Environments
Applications for steel that involve aggressive environments with corrosion coupled with high wear conditions are especially aggressive and have traditionally used electroplated "engineered" hard chrome (EHC) for protecting the steel. While other electroplated metals provide good corrosion resistance (like cadmium (Cd), Zinc Nickel (ZnNi)), they are removed quickly under wear conditions, leaving the steel exposed to corrosion. In recent years, there has been a push to reduce usage of toxic hard chrome plating for worker health and safety reasons.
Nanovate CoP Plating
Integran has developed an electroplated nanocrystalline Cobalt, called Nanovate CoP (also referred to as nCoP), that is a drop in replacement for hard chrome plating. The process has over 2 million amp hours through it in production, is very stable, and there are industrial components in the field since 2008.
Integran licenses the technology to interested parties (currently deployed to Navair, Pratt and Whitney, and Enduro Industries), and offers low volume production and application engineering through it's facilities in Toronto. The material is particularly well suited for sliding wear applications (hydraulics, pneumatics) and high chloride corrosion environments (salt spray, muriatic acid wash-downs etc.).
The material/process has the following benefits:
1) Lower Labour Cost
The Nanovate CoP has a high deposition efficiency (over 90% vs 15-25% for hard chrome) allowing parts to be processed at incredible speed. With plating rates of up to 200 microns/hour (imagine 30 microns in 8 minutes!), your labour rate for plating your parts will go down dramatically. Given this is usually ~50% of plating a part, the savings can be significant.
2) Lower Plant/Electrical Costs
The high deposition speed also opens the door to replacing multiple chrome lines with a single Nanovate CoP line. This reduces the plant cost per processed unit.
If your plant is processing parts at peak capacity with the plating process being the bottleneck, plating using the Nanovate CoP process offers a way to increase your capacity.
On the maintenance, repair and overhaul (MRO) side, repairs requiring thick build-up can be processed much quicker, resulting in less downtime for customers and a shorter backlog for suppliers.
In addition, instead of wasting 80% of your electricity generating gas and heat during deposition, you now use almost all your power in depositing metal, reducing electricity costs per part processed.
3) Higher Corrosion Resistance
The corrosion resistance of Nanovate CoP far exceeds that of hard chrome because the material is not microcracked. There is no need for expensive Nickel underlayers that are common with hard chrome usage in high corrosion environments.
The corrosion performance also opens the door to reducing thickness, which further reduces the cost of the part.
4) Lower Friction/Sliding Wear
The lower coefficient of friction of Nanovate CoP over hard chrome and contributes to better sliding wear performance, and therefore lower seal leakage rates.
5) Improved Fatigue Performance
In aerospace, many parts are designed based on steel strength and fatigue performance is critical in maintaining a minimum strength over repeated loading of the parts (aircraft landing gear is a great example). As the Nanovate CoP plating is a high strength structural cladding, it minimizes the fatigue debit imparted on the steel. In lower strength steels, it can actually impart a fatigue credit! This is in stark contrast to hard chrome which imparts a very significant fatigue debit, which results in heavier over-designed parts.
6) High Spalling Resistance
The high elastic limit (1.5%) of nanocrystalline Nanovate CoP makes for high spalling resistance in high strain applications. This stands it apart from other processes like thermal sprayed (HVOF) ceramic materials which have a very low strain capability and have a tendency to spall under repeated high strain applications.
The Nanovate CoP process specifications are locked and the process is under review for both AMS (Aerospace Materials Specification) and Mil-Specs. We expect these to issue mid-2013.
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