Heat Transfer Coefficient of coatings?

[wchowe]

Hi All
I have an application, with mostly aluminum parts. I have a central block that is water cooled. I have exterior parts that are bolted to the central block. I do not want to impede the heat transfer from the outside block to the inside cooling block. However, I would like to plate the parts so that I can increase reflectivity. I want to reflect as much heat as possible. This is a welding head, so close proximity to the heat source.
I was going to use an electroles Nickel coating for reflectivity but I haven't been able to find any info on thermal conductivity? I want to make sure I don't insulate the mating surfaces. I would have to mask the plating if the plating hurts the transfer.
Any suggestions or comments appreciated.

Thanks
Bill

 

[coatingengineer]

Hi, Bill. It's my understanding the electroless nickel-diamond co-deposit on aluminum has increased heat transfer 10% or more.

William Gunnar

http://www.IndustrialCoatingsWorld.com

 

[unclesyd]

I concur with coatingengineer there is an improvement when aluminum s plated with electroless Ni. one reason is that Al oxide that form on non protected Al is function as an insulator, both thermal and electrical.

Here is a another coating from Alumiplate that may meet your requirements. We used this as a front surface mirror in the near infra-red and few other things.
I would give them a call to get specific data for your requirements.

http://www.alumiplate.com/html/properties.html

 

[wchowe]

Looks like a good choice for my application. Reflective and heat transfer. They state three times the heat transfer of steel(k=26). That doesn't quit get you back to aluminum (k=130) but its better. I know its a very small insulating layer, but every part seam between the heat source and the water is another resistance that adds up.
The reason for plating is heat reflection and easy surface cleanup. I keep going back and forth with the tradeoff of heat transfer with the plating. Any thoughts?

Thanks
Bill