Effect Of Heat Treatment On Tribological Behavior Of Superalloys Ni-Cr-Al-Mo Coatings Obtained By Thermal Spraying

The purpose of this work is to produce metallic coatings, in powder form on nickel-based onto a steel type E335 by the technique flame spraying. To improve the properties of these coatings, post-treatments are recommended in order to homogenize them and allow obtaining better mechanical properties. These coatings were subjected to post-treatments at different temperatures 400, 600, 800 degrees C and maintained for 1 hour and cooled in air. The structural and microstructural characterization of the powder and coatings is obtained using the scanning electron microscope (SEM) and X-ray diffraction (XRD). Measures micro hardness was also performed on the surface of the coatings. The tribological tests were carried out with a pin-disk configuration under different load, with two sliding velocities in order to determine the wear rate. The microstructural results showed that the treatments carried out at temperatures of 400 and 600 degrees C present a homogeneous lamellar morphology, denser and more compact and reduced the porosities by the clogging phenomenon. Otherwise, the post-treatment at 800 degrees C caused a delamination at the interface substrate / coating. The tribological test results revealed that the sliding velocity and the applied load influenced the variation of wear rate and the coatings annealed at 400 degrees C exhibited an excellent wear resistance than that of the as-sprayed and annealed coating at 600 and 800 degrees C.