Tribological properties of La2O3 and CeO2 doped CoCrW coatings deposited by supersonic plasma spraying

Abstract

A novel supersonic plasma spraying was used to prepare rare earth oxides doped CoCrW coatings. X-ray diffractometer, contact surface profiler, hardness tester, micro-friction and -wear tester and environmental scanning electron microscope equipped with energy dispersive X-ray spectroscopy were employed to investigate the phase structure, surface morphology, microhardness, friction and wear properties of the sprayed coatings. The results show that rare earth oxide doped coatings have high microhardness and excellent tribological properties. Furthermore, the friction and wear mechanisms of sprayed coatings are also discussed.supersonic plasma spraying, CoCrW coating, rare earth oxide, tribological property CoCrW coatings with high oxidation resistance [1] , hardness and wear resistance have been used in the aeronautical field [2,3] . In the literature, CoCrW coatings are usually prepared with high-velocity oxy fuel (HVOF) [1] , plasma spraying (PS) [4,5] , and vacuum melting method (VMM) [6] . While CoCrW coatings prepared with supersonic plasma spraying (SPS) have not been reported because SPS is a novel technology.Compared with HVOF, PS and VMM methods, SPS has higher process temperature (up to 10000℃) and gas velocity (600 m/s) [7] . As hot spraying coating properties and microstructure are principally determined by the temperature and velocity of the sprayed droplets when impinging on the substrate, SPS is promising to gain higher strength, hardness and lower porosity than those of HVOF, PS and VMM methods.In this study, a kind of rare earth oxide doped CoCrW coatings are prepared with this novel SPS method and the wear resistance at low load is presented.

Photoluminescence enhancement induced by nanoparticles from La2O3 and CeO2 doped diamond-like carbon films

“…CeO 2 /MgF 2 double layer anti reflection films reduce the reflectance to lower than 1.87%, which can replace the conventional anti-reflect materials, such as ZnS, TiO 2 and Ta 2 O 5 , and produce low-cost solar cells with high conversion efficiency [23]. Furthermore, in our previous study, La 2 O 3 and CeO 2 as dopants exhibit excellent tribological, thermal, and mechanical properties in Cr 3 C 2 -NiCr [24,25] and CoCrW [26,27] coatings. The doping of La 2 O 3 and CeO 2 into DLC films, respectively, correspondingly shows good tribological [28,29] and mechanical [39,31] properties, and do not change the amorphous DLC matrix.…”

Sliding Wear Behavior of HVOF-sprayed Cr3C2–NiCr/CeO2 Composite Coatings at Elevated Temperature up to 800 °C

“…For example, they can be used to modify the solidification process and microstructure of various coatings, decrease the melting point of alloys and form rich compound in eutectic structure, showing refining and purifying effects [2][3][4][5]. So far, some commonly used rare earth elements and compounds have been doped into various surface protective materials through a variety of surface processing techniques including electrodeposition [1], laser cladding [2,4,5], and thermal spraying [3,[6][7][8][9]. And much attention has been paid to the improvement of the surface properties of various working components by rare earths, which is of significance in engineering for combating against wear, corrosion, and oxidation of surface engineering components in harsh environments, e.g., at elevated temperature [8,10,11].…”

Optical characterization of hydrogen-free CeO2 doped DLC films deposited by unbalanced magnetron sputtering

“…CeO 2 / Fe 3 O 4 film deposited on glass has been used as solar control glass, which makes the solar energy transmittance to be 50% and 65%, respectively [14]. Furthermore, CeO 2 film has excellent thermal stability and irradiation resistance [15], CeO 2 powder does not decompose even at extremely high temperature [16,17] and CeO 2 has excellent tribological and mechanical properties as dopant [18,19]. CeO 2 is therefore promising as a dopant to improve the optical properties, reduce reflectance and decrease degradation A novel kind of hydrogen-free CeO 2 doped diamond-like carbon (DLC) films with thickness of 180-200 nm were deposited on silicon by unbalanced magnetron sputtering.…”