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To tackle mechanical structure instability and low conductivity of silicon-based anode materials, Si nanoparticles enclosed in N, P doped double carbon (N, P-Si/CNTs/C) are designed and manufactured by simple mechanical ball milling and high-temperature carbonization methods. The mechanical action makes carbon nanotubes (CNTs) and silicon particles evenly and tightly intertwined, and a uniform and stable pitch-derived carbon layer is formed on the surfaces of Si particles and CNTs. The N, P-Si/CNTs/C composites have strong oxidation resistance, excellent electrical conductivity and more defects. N, P-Si/CNTs/C composites exhibit positive lithium storage performance as anode materials for lithium-ion batteries. The initial discharge/charge specific capacities of N, P-Si/CNTs/C electrodes are 1494.0/1243.6 mA h g−1 at 0.2 A g−1 with an initial coulombic efficiency of 83.24 %, yet it maintains 603.9 mA h g−1 after 100 cycles with the initial coulombic efficiency of 83.24 %. The specific discharge capacity is 1153.6 mA h g−1 even at 0.5 A g−1. The efficient lithium storage performance is due to the three-dimensional double-carbon network to effectively protect Si nanoparticles from oxidation, increase cycle stability and rate capability, and buffer volume expansion of Si nanoparticles. Doping with N and P can provide a lot of active sites and help the electrolyte penetrate. • Si nanoparticles confined in N, P- doped double carbon is designed and prepared. • N, P-Si/CNTs/C composites exhibit excellent lithium storage performance as anode materials. • The three-dimensional double-carbon network guarantees the structural stability. [ABSTRACT FROM AUTHOR]

The production of graded cubic boron nitride (cBN) tool materials starting with cBN-TiC-Al-Co mixture and having a three-layer symmetrical graded structure were obtained by high temperature high pressure method. In the first part, the design model which proposed a component gradient of cBN varied from 4 vol% to 10 vol% accompanied with Al and Co varied from 2 vol% to 5 vol% between the surface and interior was presented. Afterwards, the rationality of the graded structures were verified by the thermal residual stress analysis in the composites. In the second part, the relationships between the mechanical properties and the thickness ratio, sintering temperature, holding time as well as the component gradient were investigated. The significant gradients of the elements of Al and Co were detected in the graded cBN composites. When the temperature converted from 1350 °C to 1550 °C, the liquid phase sintering and reaction process were confirmed, leading to the formation of AlN, AlB 2 and Co 2 B. The excellent samples with a thickness ratio of 0.3 and a cBN gradient of 6 vol% acquired a homogeneous microstructure with no obvious defects under a pressure of 5.8 GPa at 1500 °Cfor 10 min. The optimum mechanical properties were achieved a flexural strength of 710 MPa and a hardness of 36.5 GPa, which was higher than that of the monolithic material with a cBN content of 80 vol%. The crack deflection and bridging played the main role in the toughening mechanism, reflecting a significant contribution of the residual stress to the mechanical properties. • The graded structure was introduced to the cBN cutting tool material to improve the strength and toughness, acquiring a flexural strength of 710 MPa and a hardness of 36.5 GPa. • The residual stress induced by the graded structure was the main toughening and strengthening mechanism, characterized by crack bridging and deflection. [ABSTRACT FROM AUTHOR]

To prevent the agglomeration of silicon carbide whiskers (SiC w) in photosensitive ceramic paste, a butanone-ethanol azeotropic solvent is employed to facilitate the dispersion of alumina particles, SiC whiskers and UV resins. Moreover, SiC w /Al 2 O 3 ceramic pastes, with 5–15 vol % SiC w , are prepared by using ball milling, stirring and distillation processes. The mixture of butanone-ethanol solvent and resins can be effectively separated at 70 °C without weakening the polymerization of UV resin. Moreover, an empirical equation is established to evaluate the relationship between SiC w content, aspect ratio and viscosity of resulting ceramic paste. The 15 vol % SiC w /Al 2 O 3 composite ceramic, with SiC w aspect ratio of 50, renders higher resistance to liquid flow and results in a high viscosity of 30,000 mPa s at the shear rate of 30 s−1. Furthermore, a modified equation is established to predicate the curing depth of ceramic pastes with different amounts of SiC w , where 15 vol % SiC w /Al 2 O 3 composite results in higher light scattering properties, leading to lowest C d of ∼0.061 mm. Finally, the complex-shaped SiC w /Al 2 O 3 ceramic component, prepared by SL 3D printing technology, debinding and sintering processes, exhibited a superior fracture toughness of 7.1 ± 1.20 MPa m1/2 and a higher hardness of 17.6 ± 0.78 GPa. • A novel technology was proposed for preparing a 50 vol% SiC w /Al 2 O 3 photosensitive paste. • The dispersing process can effectively prevent the agglomeration of SiC whiskers. • 5-15 vol% SiC w contents influence on the pastes corresponding properties were evaluated. • Complex SiC w /Al 2 O 3 part with 7.1 ± 1.20 MPa m1/2 was 3D printed and sintered. [ABSTRACT FROM AUTHOR]