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Tungsten Carbide Coatings for Aluminum? Airboat Hull Coating?

Q. We make 2,4 by 6 m aluminum airboats that take six people and travel mostly on frozen sea and lakes. The boat has a flat bottom curved on the sides with a 150 mm radius. The aluminum surface is protected by a 10 mm UHMW Polyethylene sheet which is bent around the sides with hot air and the screwed in place with hundreds of stainless screws. Bending the PE is very tedious and the boat is full of (screw) holes. Is there any other way of making a hard coated surface that can be done in a boat yard? Aluminum oxide?

Henrik Paersch
company owner - Helsinki, Finland
2004

A. I'm not sure that Teflon impregnated hardcoat anodizing would fully meet your needs, but it might, and it would certainly be a more practical coating to apply.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2004

A. Have you tried preheating the UHMW before hot air bending? Infrared of a proper frequency should work as well as be an affordable and semi-portable. Have you looked at automatic screw guns? Considering your size and application, I would be very surprised if Teflon impregnated hard coat would last very long.

James Watts
- Navarre, Florida
2004

A. How about ceramics, Diamond-Like Carbon, aluminum carbide etc? Are there any way of making a thick ceramic coating on aluminum?

Henrik Paersch
- Helsinki, Finland
2004

A. I do not think that ceramics will work for you as they are brittle. If your aluminum flexes much, I would expect it to delaminate. You might want to take a look at nickel aluminide that is arc sprayed rather than flame sprayed. It tends to be a laminar coating rather than columnar or cast like. There are some very strong and tough materials that can be sprayed with HVOF, but this is considerably more expensive to purchase and maintain.

James Watts
- Navarre, Florida
2004

A. Thick, wear-resistant coatings are often applied by thermal spray methods like HVOF (high velocity oxy fuel). The US military is investigating tungsten carbide HVOF coatings as a replacement for hard chromium plating. Sulzer is probably the world's leading supplier of these coatings, so you may want to discuss it further with them.

Toby Padfield
Automotive module supplier - Michigan
2004

A. I think the problem in your boat is corrosion, wear and thermal shock in the material.
I think Al₂O₃ coating using plasma spray iso not good because it has many vertical cracks in the coating and a low fracture toughness. But you can choose other material such Al₂O₃/TiO₂ type of powder fuse or nanomaterial.
About the Al₂O₃/TiO₂ nano powder is very excellent of bending (in the paper) and higher fracture toughness than Al₂O₃ coating.
In agreement with James Watts about nickel aluminide using Arc spray. It establishes and conveniences for the coating and lower cost than HVOF and VPS.

N. Dej
Student - Finland
July 17, 2008

A. Why not just thermal spray the polyethylene coating on? Polyethylene is the easiest to apply and most popular thermal spray polymer coating, however with current technology, only LDPE coatings can easily be applied. We have developed a way, experimentally, to apply an HDPE coating that may work for you. We are looking at doing some tests on "mud boats" and "mud motors" in Louisiana.

Jim Weber
- West Babylon, New York
May 26, 2010

A. I have been testing the Wetlander airboat slick bottom coating on a base layer of sprayed polyurea, aka, Line X. The Line-X polyurea provides impact resistance while the Wetlander provides a low coefficient of friction, allowing the normally "grippy" polyurea to be super slick.

Scott Hogan
industrial coatings development - Saratoga Springs, New York, USA
March 7, 2012

Multiple threads were merged: please forgive repetition, chronology errors, or disrespect towards other postings [they weren't on the same page] :-)

Tungsten carbide coating on aluminum

January 13, 2010

Q. Dear sir,
We have some parts for our machine.we want to coat Tungsten carbide (88%) and cobalt (12%).
Base material is aluminium.
Coating thickness is 0.025".
Plate size 0.115" Thk x 4" Long x .375" width.

It's possible to coat on aluminium?

Bhavesh Thekdi
- Vadodara, Gujarat, India

A. HVOF guns can apply WC coatings that thick and more but hardly will your substrate withstand the temperature and pressure. Perhaps with special fixturing and cooling. Sintering is also limited by the low melting point of aluminum. Maybe an ESD coating, but its thickness will be around 0.002-0.004".

Guillermo Marrufo
Monterrey, NL, Mexico
January 16, 2010

A. Look up thermal spray which would include high energy and flame spray. Plasma spray might be a bit too hot for aluminum, You might look at HVOF as a possibility.

James Watts
- Navarre, Florida
January 18, 2010

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