Alpha Metal Finishing provided a hardcoat anodizing lunch and learn presentation in May 2014. Special thanks to Rob Pawson from Reliant Aluminum Products for assisting us.
3. “However beautiful the strategy,
you should occasionally look at the results.”
--Sir Winston Churchill
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5. What is Anodizing?
Anodizing is an electrochemical process that converts the metal surface
into a decorative, durable, corrosion-resistant, anodic oxide finish. The
anodic oxide structure originates from the aluminum substrate and is
composed of aluminum oxide.
This aluminum oxide is not applied to the surface like paint or plating,
but is fully integrated with the underlying aluminum substrate, so it
cannot chip or peel. It has a highly ordered, porous structure that allows
for secondary processes such as coloring and sealing.
More info at www.anodizing.org
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8. What is Hardcoat Anodizing?
Hard anodized coatings or hard anodizing (Type III) is similar to
standard anodizing, (Type II) in as much as it also creates a film of
aluminum oxide on the part.
It is produced at colder temperatures (typically 30 °F) with much
higher voltage and current. This provides a surface that is harder and
more wear and corrosion resistant than standard anodizing.
9. Some of the characteristics of hardcoat:
Hard anodized coatings can be grown to greater thickness, typically
.002 inches or more
50% penetration and 50% buildup per surface
Hardcoat finishes are typically darker in appearance than standard
anodizing depending on the coating, thickness and alloy
Hardness – Rockwell scale rating of C - 60 / 70
10. Benefits of Hardcoat:
Corrosion Resistance
Variable Thickness – smaller tolerances than previously available
Wear Resistance
Resistance to chemicals, solvents and petroleum based products
Electrical Resistance
Temperature Resistance
Low Friction Coefficient after Lubrication
11. To Seal or Not To Seal?
After a component has been hardcoat anodized, it may or may not be
sealed.
If the main purpose of the application is to obtain a maximum degree
of abrasion or wear resistance then the coating should not be sealed.
If the main purpose of the application is for corrosion resistance and
reduced abrasion resistance is not a concern, sealing is advised.
12. Some of the potential challenges that come into play during the
hardcoat process:
Dimensional Growth and Crucial Tolerances
Threads and Holes
Sharp Corners and Points
Different Alloys
Racking Concerns
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18. PTFE, or polytetrafluoroethylene coating, provides many benefits to
hardcoated parts:
Low Coefficient of Friction
Chemical Resistance
Heat Resistance
19. Alpha provides a systematic, tightly controlled process for our hardcoat
customers:
Surface area is calculated prior to processing
Utilize a proprietary coating thickness algorithm to achieve consistent
coating thickness results
Our control system and process significantly reduces the risk of burning of
parts, particularly 2024 alloys
20. Alpha can provide color hardcoat options to customers with a variety of
colors.
Material Preparation
Alloys and How They Affect Color
Hardcoat Applications
