Who can tell me how to spray on carbon?

[lifei]

I want to spray on Carbon(graphite) or Fiber Reinforced Polymers ,how can i do? if i need to blast at first? thanks!

[derek]

I used to spray TBC on Graphite plate for vaccume furnace to stop Carbon transfer to part during heat treatment in high temprature. I blast the graphite and spray TBC on it without bond coat. It works well, we have to re-spray TBC on it every year because the furnace operator scratch the TBC during orperation.

What kind of powder do you want to spray on it?

[Gordon]

Hi lifei

to the Surface Engineering Forum.

Could you give us a bit more information? Coating, function, application etc.

Derek's suggestion is good for graphite furniture on vacuum furnace. But not good for Fibre Reinforced Polymers, as a totally different approach will be needed and probably a good deal of experimentation to get things right.

[lifei]

(08-24-2010 04:03 PM)derek Wrote:  I used to spray TBC on Graphite plate for vaccume furnace to stop Carbon transfer to part during heat treatment in high temprature. I blast the graphite and spray TBC on it without bond coat. It works well, we have to re-spray TBC on it every year because the furnace operator scratch the TBC during orperation.

What kind of powder do you want to spray on it?

thanks derek for
Can you tell me the details for blast the graphite ? you know,the graphite if very soft.

---

(08-25-2010 12:22 AM)Gordon Wrote:  Hi lifei

to the Surface Engineering Forum.

Could you give us a bit more information? Coating, function, application etc.

Derek's suggestion is good for graphite furniture on vacuum furnace. But not good for Fibre Reinforced Polymers, as a totally different approach will be needed and probably a good deal of experimentation to get things right.

thanks very much
"Recent development work has indicated promise for engineering type thermal spray coatings on fibre reinforced polymers. Careful selection of material combinations and the use of special process parameters has produced relatively thick coatings in metals, ceramics and carbides which can be machined or ground."
I want to spray WC on Carbon Fibre Reinforced Polymers,like you say ,bond strength is very low,how can i select bond layer?thanks!

[Gordon]

Hi lifei

Quote:"Recent development work has indicated promise for engineering type thermal spray coatings on fibre reinforced polymers. Careful selection of material combinations and the use of special process parameters has produced relatively thick coatings in metals, ceramics and carbides which can be machined or ground."
I want to spray WC on Carbon Fibre Reinforced Polymers,like you say ,bond strength is very low,how can i select bond layer?thanks!

I'm afraid I can't give away too much information on this subject. Just to say a considerable amount of development work may be necessary.

Important and potential problematic stages:

* Surface condition and make-up of composite substrate
* Shape and size of composite substrate
* Cleaning and grit blast preparation - bristly finish may sound good but is not IME
* Other possible substrate preparation/coatings
* Thermal spray application and choice of a bond coat system
* Thermal spray application of top coat

The last two require a lot of attention to process methods. The main issue being temperature control and rate of deposition per pass.

[warx]

(08-26-2010 04:38 PM)Gordon Wrote:  Hi lifei

Quote:"Recent development work has indicated promise for engineering type thermal spray coatings on fibre reinforced polymers. Careful selection of material combinations and the use of special process parameters has produced relatively thick coatings in metals, ceramics and carbides which can be machined or ground."
I want to spray WC on Carbon Fibre Reinforced Polymers,like you say ,bond strength is very low,how can i select bond layer?thanks!

I'm afraid I can't give away too much information on this subject. Just to say a considerable amount of development work may be necessary.

Important and potential problematic stages:

* Surface condition and make-up of composite substrate
* Shape and size of composite substrate
* Cleaning and grit blast preparation - bristly finish may sound good but is not IME
* Other possible substrate preparation/coatings
* Thermal spray application and choice of a bond coat system
* Thermal spray application of top coat

The last two require a lot of attention to process methods. The main issue being temperature control and rate of deposition per pass.

to carbon fiber parts we do a ligth sand blast, wirespray zinc as bond coat, and them spray the desired coating by flamespray.

[lifei]

why "wirespray zinc as bond coat", thanks!

[LEN WOOD]

Hi lifei,

Sorry to butt in.....
Although the tensile adhesion strength of zinc coatings is relatively low, being ductile they are very tolerant of handling and other impact damage. They facilitate a great bond on many substrate materials particularly non metals, where little or no surface preparation is required

Obviously you will need to do some testing/R & D to see if it will work for your particular application(s)

[loriolo]

(08-24-2010 02:20 PM)lifei Wrote:  I want to spray on Carbon(graphite) or Fiber Reinforced Polymers ,how can i do? if i need to blast at first? thanks!

To spray some material on graphite, it's enough to clean the surface with some abrasive paper, but to spray on Fiber Reinforced Polymers, you need to blast with low pressure and 100 micron aluminum oxide blasting powder.

[wilfred1963]

have sprayed carbon seals in the past with Metco 53-10 but prep was a bit of a timely op. we soaked them in ethanol and water 50/50 mix for an hour then oven bake at 250 degrees for an hour then blast with 180 grit at 30 psi bonding was a non issue and we were able to coat up to 30 mils in thickness before lifting began. R@D is key here for carbon very temperamental substrate.

[joyee]

I used to spray TBC on Graphite plate to stop Carbon transfer to part during heat treatment in high temperature.


Although We say welcome to you on this forum.