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Any chemical solution for increasing bonding strength in THERMAL SPRAYING

2007

Dear sir,

We are thermal spraying company in india. we have problem to recoat on wasted cutting tool insert. We cannot attain the bonding with coated material and substrate. Coated material is W\10%Co. substrate material is ceramic cutting tool. So please advice any chemical solution for increasing bonding strength on substrate.

thanks,

P.SUMANRAJ
HI TECHNOLOGY ENGINEERS - COIMBATORE

WC+Co and ceramics are so different (physically and chemically) that they are not so compatible. Also your coating process is not compatible with super hard and brittle base materials. I do not understand your idea. If you want to coat a ceramic part, maybe you need more ceramic of the same quality on top.

Guillermo Marrufo
Monterrey, NL, Mexico
2007

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2007

Dear sir

Thank you for your response. We are coating carbide on waste and wear carbide cutting tool inserts and cermaics. I want to increase bonding strength on carbide cutting tool. any other chemicals is there for increasing bonding strength carbide cutting tool. process is thermal spraying.

thanks

Sumanraj
hi tech engineers - India

As you know, thermospraying obtains its adhesion only by mechanical "lock". Roughness and impact energy are the main factors. Suitable substrates are normally soft to mid-hard. Tungsten carbide is too hard and dense. Even if you could roughen its surface chemically, the sprayed particles will not be able to distort the surface upon impact and adhesion would be marginal. Do you plan to restore the inserts to cut again? Maybe you should investigate sintering process.

Guillermo Marrufo
Monterrey, NL, Mexico
2007

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dear sir

yes sir. we are planning to cut again after thermal spraying. at least we will plan to get 50% life of new cutting insert. please advise as best coating material and which process is very suitable for it. the substrate material is carbides.

I am waiting for your reply above

thanks

regards,

Sumanraj
hitech engineers - Tamil Nadu, India
2007

Even if you are using modern HVOF gun for increased particle velocity and deposit density, adhesion will not be enough to withstand the extreme forces and thermal shock found in cutting. Sintering more cobalt tungsten powder on top of the used inserts may be the only way. This is the way they are produced new. Perhaps not an economical approach though.

Guillermo Marrufo
Monterrey, NL, Mexico
2007