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A diffusion-modified HfC/HfC SiC bilayer system was innovatively designed and synthesized onto cemented carbide (WC-Co) substrate by reactive double glow plasma surface alloying (DGPSA) technique for adherent diamond deposition. The microstructure, phase composition and adhesion of the bilayer system were investigated, as well as its effect on the diamond coating system. The results showed that the bilayer system was made up of a 1.0-μm-thick nanostructured HfC-dominant inner layer and a 0.7-μm-thick HfC SiC mixed outer layer. As the gradient element distributions existed at the bilayer/substrate interface, the bilayer system displayed a superior adherence to the substrate. And the surface microhardness improved from 1802 HV 0.1 to 2857 HV 0.1 after the reactive DGPSA treatment. Subsequently, a uniform and dense nanocrystalline diamond coating with thickness of 4.0 μm was successfully deposited onto the HfC/HfC SiC interlayered substrate. Benefit from the effective suppression of Co diffusion by the interlayer and the reasonable design in its hardness and thermal expansion coefficient (TEC), the obtained diamond coating possessed an excellent adhesion. Therefore, the diffusion-modified HfC/HfC SiC bilayer systems synthesized via reactive DGPSA technique can be considered as a novel interlayer option for depositing adherent diamond coatings on WC–Co substrates. [ABSTRACT FROM AUTHOR]

The high-performance LiNi 0.5 Mn 1.5 O 4 has been prepared by an improved solid-state method, which is calcined in nitrogen at the first stage and in air at the second stage. The reaction process between nickel atoms and manganese atoms was changed by the improved solid-state method. The final product is a high purity cubic spinel structure (Fd3m) with high crystallinity, little impurities and excellent electrochemical performances. The EDX demonstrates that there is slightly lower nickel content and carbon content on the crystal surfaces. It shows a discharge capacity of 138 mAh/g at the first cycle and 133.9 mAh/g after 100 cycles at 0.1C rate. It also can deliver a discharge capacity of 111.3 mAh/g at 5C rate. The discharge capacity of the cathode at 55 °C is up to 124 mAh/g with capacity retention of 96.1% after 100 cycles. These results show that the improved solid-state method has potential application for the large-scale synthesis of LiNi 0.5 Mn 1.5 O 4 in high power Li-ion batteries. [ABSTRACT FROM AUTHOR]