Metal finishing Q&As since 1989

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Surface coating for the aluminium soleplate of an iron

August 2, 2011

Hi everybody!

I'm working for a company which products irons and as project I have to find a finishing to improve the aluminium soleplate of our irons.

I have as objectives (in order of importance):
- improving the gliding of the soleplate(low friction coefficient)
- keeping a good thermal conductivity
- improving resistance abrasion

All the solutions are possible.

After a little study, I've fund several interesting methods:
- shot peening which is the most economic but I don't know if it can be damaging for the soleplate (very thin).
- electroless nickel with PTFE
- Sol-gel method

I've avoided ceramic projections and anodization because of the thermal expansion coefficient and Polymer powder coating.

Can you tell me if one is better than the others?

Thanks for your answers and sorry for my English...

Guillaume B.
student - Lausanne, Vaud, Switzerland

Hi, Guillaume.

The usual reason for shotpeening is to induce compressive stress to enhance fatigue strength, although it's sometimes used for decorative effect. But whether shotpeened or not, I doubt that bare aluminum is satisfactory for the soleplate.

Electroless nickel with teflon sounds excellent, although expensive. Chrome plating might be an alternative .

To my knowledge, sol-gel is as much an application method as a specific coating. You would need to determine whether you are thinking of an oxide coating or a hybrid organic-inorganic coating, etc.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
August 2, 2011

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August 5, 2011

Thanks a lot Ted for your answer!

I'm making some samples with soleplates which will be shot peened and I will see if the bare aluminium can support a duty cycle (without contamination or scratches). I will tell you if it works.

Furthermore, you're right I need to precise for the sol-gel method. I've heard that with oxides we will have again a risk of cracks so we would prefer to coat with a organic-inorganic hybrid. However, I've heard that some people (concurrent) used an inorganic polymer based on polysilicates, do you think both are possible?

For the application method there are several possibilities like dip coating for example but it's not the main problem.

Anyway, I'm going to ask some professional shops.

Finally, for the electroless method I'm too trying to make some samples with some suppliers.

If you have more information about this topic, let me know.

Best regards.

Guillaume B.
- Lausanne, Switzerland