Victrex is introducing a new, cost-effective flame spray process for applying its Vicote coatings to metal and ceramic substrates. Historically, thermal (flame) spray technology has been limited to the application of metal alloys, cermets and some low-performance polymers to form a protective coating on the substrate, but all of these coatings have performance limitations despite continued research to develop the process for high-performance polymers. The new technique is claimed to be the first to successfully flame spray a Victrex Peek polymer-based coating onto a metal substrate, resulting in a tough, durable, high-temperature and chemically resistant coating.
Victrex worked closely with the Alamo Supply Co of Houston, Texas, USA, which designed the PG550 Universal Flame Spray System providing cost-effective thermal spraying. Easy to use and set up, the equipment features an innovative gun nozzle that allows the sprayed polymer to form a continuous coating.
John Robinson, coatings technology leader at Victrex, states: "A stream of Vicote powder coating passes through the gun and is heated to a temperature where the powder melts and is deposited at high velocity as 'splats' on the surface of the substrate. These splats overlap as the gun is traversed across the substrate to form a tough, durable, high-performance coating. The crystalline structure of the Vicote coating is what gives it its exceptional high wear, abrasion, erosion, scratch and corrosion resistance, especially at high temperatures."
One of the major advantages of flame spraying with Vicote coatings is that it creates a high-performance coating on parts that would be difficult or costly to coat by other means. Robinson explains: "The process itself is very energy-efficient. For example, no oven is required to cure the coatings, although for thick coatings on solid shafts a stress relieving cycle may be needed. No electricity is used to power the equipment - just compressed gas."
Flame spraying, which can also be applied to thermally sensitive substrates, is suitable for coating pump impellers and pump housings. Robinson adds: "Most geometries can be flame sprayed. These include fairly complex parts due to the absence of the Faraday cage effect found when coating using the traditional electrostatic powder coating process."
Flame spraying with Vicote coatings can also be used for the repair and upgrading of in-service equipment. Robinson says: "The process also has a number of advantages for the rebuild or repair of parts. Refurbishing a worn surface by flame spraying with Vicote coatings can be more financially attractive than a complete replacement part and offers an alternative high-performance coating to traditional flame sprayed powdered metals."
For more information, visit www.vicote.com