Development of laser cladding MCrAlY coatings: high temperature friction and wear behavior

Autores UPV
Año
CONGRESO Development of laser cladding MCrAlY coatings: high temperature friction and wear behavior

Abstract

Temperature can have a significant effect on the extent of wear damage of metallic components. Thermal barrier coatings with MCrAlY alloy can improve the high temperature tribological and friction wear behavior. In this work the dry friction and wear behavior at room temperature and high temperature of new developed NiCoCrAlY and CoNiCrAlY laser cladding coatings were evaluated. Dense coatings, with good bonding to the AISI 304 substrate was obtained by coaxial laser cladding tracks (40% overlapping), with previously optimized laser parameters [1]. Tribological wear tests were performed by sliding wear at room temperature and 500 ºC, with an Al2O3 ball on disk configuration tribometer. The wear scar surface was evaluated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) microanalysis. The 3D topography of the wear track was determined by inductive contact profilometer which enabled the wear rate calculation. The microstructure of the coatings consists of Ni/-NiAl or Co/-(Co,Ni)Al phases depending on the chemical composition of the alloy, as confirmed by X-ray diffraction (XRD) analysis. The wear test results show a reduction in wear rate at high temperature for all materials tested. For the NiCoCrAlY coating, the high temperature also reduces the friction coefficient, while it significantly increases the friction coefficient of CoNiCrAlY coating. The main damage mode is abrasion and adhesion, caused by oxides and partially-oxidized particles in the contact surface. The coatings and stainless steel substrate results were compared, resulting in an improved wear behavior.