Hi there,

I would like to know what is the ideal surface preparation in order to produce plasma or flame spray metallic coatings onto CFRP substrate?

Thanks in advance.

Hi Voivod

to the Surface Engineering Forum.

Restricted to what I can say. Generally, I find every carbon fibre reinforced polymer substrate tends to be different (as with other FRPs) and usually requires some experimentation to optimise preparation and coating.

Can you expand on what you are trying to achieve?

Dear Voivod,
I had done one job of CFRP substrate for some defense project by making surface prefeperation by making cross hatches by hacksaw and sprayed zinc. I could not get feed back on above job but neither got any complaint of coating failure. I think that no news is a good news.
Vijay Deshpande

Voivod Wrote:Hi there,

I would like to know what is the ideal surface preparation in order to produce plasma or flame spray metallic coatings onto CFRP substrate?

Thanks in advance.

Hi Gordon,

We want to flame spray (wire or powder) aluminium onto a CFRP substrate. We did some preliminary tests without any surface preparation and the coating did not or partially adhere to the substrate. Using sand blast as preparation procedure, one may induce some damages onto the fibers or embeds sand blast particles into the polymer matrix. Do you think that we could sand blast (with a very low air pressure) the CFRP surface in order to enhance the adhesion of the Al coating? Is there any other alternative to sand blasting in order to increase the adhesion of the coating onto CFRP (use of bond coat, higher substrate temperature during the spray process, etc...)?

Thansk for your help.

Gordon Wrote:Hi Voivod

to the Surface Engineering Forum.

Restricted to what I can say. Generally, I find every carbon fibre reinforced polymer substrate tends to be different (as with other FRPs) and usually requires some experimentation to optimise preparation and coating.

Can you expand on what you are trying to achieve?

Hi Voivod

Thorough cleaning is important particularly if mould release agents have been used. Grit blasting is important to get reasonable bond, but this needs to done very carefully (alumina grit at lower pressure than for metals) to achieve texture without damaging or ideally not exposing fibres. Having substrate at ~30-45 C or at least above dew point may beneficial. During spraying substrate and coating temperature must be carefully controlled (try and keep below ~ 75C) Fast gun and surface speeds with minimum coating thickness per gun pass is necessary. Combustion wire or arc spray probably better than combustion powder spray.

Hope that helps