The liquid phase reduction-heat treatment has been used to prepare V2O3nanoparticles in this paper. It is a novel method that the precursor was developed by Oxalic acid dehydrate (H2C2O4·2H2O) reduction of V2O5powder in anhydrous ethanol. V2O3nanoparticles were successfully obtained by thermal treatment of the precursor. The phase, composition, structure, and morphology of the as-obtained samples were verified by XRD, XPS, SEM and TEM measurements. Meanwhile, the possible formation mechanism of V2O3in the heat-treatment is briefly discussed by analyzing the DSC.
In this paper, the rapid prototyping of W-Cu composites by laser cladding was reported. The influence of the mass ratio of W and Cu on the structure and properties were investigated. Ni and Co were added to the W-Cu composites to promote the sintering densification. The effect of the elements on the structure, phase composition and properties of W-Cu composites was investigated by using X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectrometer (EDX) and hardness test. The results showed that when Cu content increases to 60 wt.%, W particles were distributed around Cu agglomerates. When Ni content increases to 3.0 wt.%, γ-Ni phase could be observed. It was found that Co was concentrated at the interface between W and Cu phase and enhance the diffusion of W in Cu phase. Both Ni and Co could increase the density of the W-Cu composites greatly.
To extend the service life of hot die steel (H13), WC particles reinforced Co-based alloy composite coatings were produced by laser cladding. The microstructure evolution and performance of the cladding layer were investigated. The experiment results showed that there existed fine dendritic crystals and dispersive WC particles in the cladding layer. The coatings were mainly composed of γ-Co, WC and Co3W3C phases. The microhardness of the cladding layer was higher than that of the arc surfacing layer, and the microhardness gradually increased with WC content. Compared to the substrate, the friction coefficient of the cladding layer reduced greatly. The coatings with 15wt.% WC possess the best wear resistance.
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