|
4164 |
|
Wednesday, May 21, 2014, Hall H1 & H2 3:40 PM "Young Professionals" |
|
Cold spray deposition of a WC-25Co cermet onto aluminum and carbon steel substrates |
|
Miguel Couto* / Thermal Spray Centre (CPT), SPAIN Sergi Dosta / Thermal Spray Centre (CPT), Spain Josep Maria Guilemany/ Thermal Spray Centre (CPT), Spain |
|
This work is focused on the deposition of wear and corrosion resistant WC-25Co cermets on carbon steel and aluminium Al7075-T6 substrates by Cold Spraying. This technique is a solid-state deposition process in which a supersonic jet of compressed gas accelerates and heats a powder onto a substrate. Nomelting of the powder occurs, and the particles are deformed and bonded together to build up a thick layer. WC-Co cermets have been used for wear-resistant parts due to their unique combination of mechanical, physical and chemical properties. XRD tests were run on the powder and coatings to determine possible phase changes duringthe spraying process. The bonding strength of the coatings was measured by adhesion tests; their sliding and abrasive wear resistances were also studied as well as the fracture toughness of both optimum coatings obtained by CGS. The corrosion resistance was determined by electrochemical measurements and salt fog spray test. An experimental design was made to define fixed and variable parameters in order to optimize the spraying conditions. The chosen variable parameters were gas pressure and distance, with values ranging from 30 to 45bar, and 10 to 40mm, respectively. Using Cold GasSpraying for obtaining WC-25Co coatings proved to be very competitive when compared to coatings deposited by conventional thermal spraying techniques, obtainingthick, dense and hard coatings both onto aluminium alloy Al7075-T6 and carbon steel substrates, with excellent tribological and electrochemical properties. |