To solve the lack of wear resistance of titanium alloys for use in biological applications, various prepared coatings on titanium alloys are often used as wear-resistant materials. In this paper, TiC bioinert coatings were fabricated on Ti6Al4V by laser cladding using mixed TiC and ZrO₂ powders as the basic pre-placed materials. A certain amount of CeO₂ powder was also added to the pre-placed powders to further improve the properties of the TiC coatings. The effects of CeO₂ additive on the phase constituents, microstructures and wear resistance of the TiC coatings were researched in detail. Although the effect of CeO₂ on the phase constituents of the coatings was slight, it had a significant effect on the microstructure and wear resistance of the coatings. The crystalline grains in the TiC coatings, observed by a scanning electron microscope (SEM), were refined due to the effect of the CeO₂. With the increase of CeO₂ additive content in the pre-placed powders, finer and more compact dendrites led to improvement of the micro-hardness and wear resistance of the TiC coatings. Also, 5 wt % content of CeO₂ additive in the pre-placed powders was the best choice for improving the wear properties of the TiC coatings.

https://www.mdpi.com/1996-1944/11/1/58/pdf

Effect of CeO₂ on Microstructure and Wear Resistance of TiC Bioinert Coatings on Ti6Al4V Alloy by Laser Cladding.

To improve the wear resistance of titanium alloy parts used in the engineering applications, in-situ formed Ti(C,N) particles reinforcing Ni-based composite coatings are fabricated on Ti6Al4V alloys by the laser cladding technique using Ni60, C, TiN, and small amounts of CeO2 nanoparticles mixed powders as the pre-placed materials. Firstly, the formation mechanism of Ti(C,N) particles as a reinforced phase in the coating is investigated. Then, the influences of CeO2 nanoparticles on microstructures and wear resistance of the coatings are analyzed. It is indicated that the large Ti(C,N) particles form around TiN particles, and the small Ti(C,N) particles form through independent nucleation. CeO2 nanoparticles play important roles in increasing the nucleation rate and improving the precipitation of Ti(C,N), hence the microstructures and wear resistance of the coatings are apparently improved after adding CeO2 nanoparticles. It is observed that the 1 wt % content of CeO2 additive in the pre-placed powders is the best choice for the wear resistance of the coatings.

Laser Cladding In-Situ Ti(C,N) Particles Reinforced Ni-Based Composite Coatings Modified with CeO2 Nanoparticles

AlCoCuFeMnNi high-entropy alloy coating was prepared by plasma cladding method. The phase structure and microstructure of AlCoCuFeMnNi coating was investigated by XRD, SEM and EDS respectively. The results show that AlCoCuFeMnNi caotings have two BCC phase structure and typical dendrite structure and form good metallurgical bonding with substrate. The dendrite is the typical spinodal decomposition structure. After CeO2 doping, the change of peak intensity and FWHM is obvious due to the effect of Ce on the improvement of grain growth, microstructure and crystallinity. The addition of CeO2 is beneficial to reduce the cladding defect, make dendrite arm spacing enlarged and spinodal decomposition structure refined, and improve element segregation owing to the melioration effect in the temperature gradient, solidification rate, fluidity, wettability, and surface tension.

/pdf/effect-of-ceo2-doping-on-phase-structure-and-microstructure-3lf13r1r60.pdf

Effect of CeO2 Doping on Phase Structure and Microstructure of AlCoCuFeMnNi Alloy Coating

TiC4 ceramic layer modified by CeO2 was deposited on 45 steel substrate by laser-cladding technique.The phase composition,microstructure and microhardness of the clad coating were analyzed by SEM,XRD and micro-hardness tester.The results show that the TiC4 ceramic coating prepared by laser-cladding method had typical surrounding phase and hard spot phase structure.Density of the coating was improved,TiC4 particle size was less than 1 μm and the average micro-hardness increased to 700 MPa when 0.3wt%-1.0wt% CeO2 was added.Adding exccess(≥1.5wt%) CeO2 would make adverse effect on the coating micro-hardness,i.e.,the surrounding phase content and TiC4 particle size increased,and the TiC4 grain was lance-shaped and the micro-hardness decrased to 450 MPa.

He Jun

Papers

Influence of CeO_2 on Microstructure and Microhardness of TiC_4 Coating Produced by Laser-Cladding