Thermal diffusion coatings for corrosion protection –
and for additional capabilities, as well

Greenkote® thermal diffusion corrosion protection coatings are available in three groups  — PM-1, PM-10, and PM-21 — to provide a range of thickness, hardness and other characteristics. And within each group the specifications may be varied to tailor a coating to specific applications, topcoats or other requirements.

The chart at the bottom of this page includes an extended list of Greenkote coatings that cover many applications beyond corrosion protection.

Using a proprietary thermal diffusion process, all of the Greenkote formulations offer exceptional corrosion resistance as well as strong adhesion, superior wear resistance, low friction, elimination of hydrogen embrittlement and excellent bonding to rubber, plastic and other topcoats.

Greenkote PM-1:  15–100 µm thicker coatings

PM-1 is a diffusion sacrificial corrosion-resistant coating of Zn-Al polymetallic composition. Its specific thickness can be adjusted to suit different applications, from 15 to 100µm. PM-1 is well suited for marine, industrial, and other challenging environments, including heavy construction projects that require superior long-term corrosion resistance combined with excellent torque lubricity and torque retention. And for applications needing additional hardness you may select the PM-1H process.

Greenkote thermal diffusion coatings compared. Click chart to enlarge.

PM-1 corrosion protection coatings are ideal for carbon and low-alloy steels and cast irons. A good stainless steel replacement, it is also recommended for sintered and MIM parts. It is an excellent basecoat for painting, duplex coatings, adhesives and rubber to metal molding.

This coating line offers:

• Surface hardness up to HV 400 to 550
• Tested salt spray resistance up to 1200+ hr
• Long-term corrosion protection up to 600°C (1112°F)
• Resistance to damage during crimping and bending operations
• Low friction and resistance to seizing and galling
• May be welded in certain applications

Greenkote PM-10 and PM-21:  5–15 µm thinner coatings

Greenkote developed PM-10 and PM-21 thermal diffusion coatings mainly as a base layer for corrosion protection, and they are typically used with one or more topcoats, friction modifiers or sealers to achieve optimal performance. These thinner Greenkote coatings (5–15µm) work well for small, fine-threaded fasteners with standard and high-strength specifications. These are thin, diffusion sacrificial coatings for carbon and low alloy steels and cast irons.

PM-10 has zinc-aluminum composition and is recommended for stamped parts. PM-21 has zinc-aluminum-magnesium composition and is recommended for fasteners.

Additional advantages:

• Uniform coating thickness for difficult part geometries
• Surface hardness up to HV 320 to 400
• Uniform tightening torque
• Resistance to damage during crimping operations
• Long-term corrosion protection up to 350°C (662°F)

And Greenkote capabilities extend beyond corrosion protection…

Greenkote PM thermal diffusion coatings are zinc based and provide galvanic corrosion protection for iron-based alloys along with improved hardness and adhesion to topcoats. But Greenkote’s technology is a platform that can be adapted to enhance performance in other types of coating applications, as well – such as those requiring high-temperature oxidation resistance (e.g., aluminum based), increased hardness or wear resistance (e.g., vanadium, titanium & chromium) anti-seizing or reduced friction. The following chart may give you some ideas.

If you have a special need, please give us more details and our engineering team will see if there is a Greenkote solution for you!

Greenkote can provide diffusion coatings for additional applications beyond corrosion protection. Click chart to enlarge.

Greenkote^® and the Greenkote logo are registered trademarks of Greenkote PLC.