Search

Your search keyword '"He, Yang"' showing total 3 results
Start Over Author "He, Yang" Topic microstructure Journal ceramics international
3 results on '"He, Yang"'

1. Photocatalytic antibacterial properties of copper doped TiO2 prepared by high-energy ball milling

Author

Juncen Qian, Dai Shi, Mei Wang, He Yang, and Qianfei Zhao

Subjects
010302 applied physics, Materials science, Scanning electron microscope, Process Chemistry and Technology, Doping, chemistry.chemical_element, 02 engineering and technology, 021001 nanoscience & nanotechnology, Microstructure, 01 natural sciences, Copper, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, X-ray photoelectron spectroscopy, chemistry, 0103 physical sciences, Materials Chemistry, Ceramics and Composites, Photocatalysis, Diffuse reflection, 0210 nano-technology, Ball mill, Nuclear chemistry
Abstract

TiO2 nanopowders and Cu-doped TiO2 were prepared by high-energy ball milling and characterized by X-ray diffraction (XRD), UV–vis diffuse reflectance (UV–vis - DRS) spectra, a scanning electron microscope (SEM), an energy dispersive spectrum (EDS) and an X-ray photoelectron spectrometer (XPS) to study the effect of Cu doping amount, milling time and balls-to-powder ratio on the microstructure and antimicrobial activity of the nanopowders. The results show that the mean size of the powders is reduced to below 100 nm after 3 h of milling. The prepared copper-doped TiO2 powders have excellent antibacterial activity against the Gram bacteria, which depends on the degree of copper doping.

Published
2020

2. In situ synthesis, mechanical properties, and microstructure of reactively hot pressed WB4 ceramic with Ni as a sintering additive

Author

Ke Ma, Xiaozhou Cao, Tao Jiang, Xiangxin Xue, and He Yang

Subjects
Materials science, Process Chemistry and Technology, Sintering, chemistry.chemical_element, 02 engineering and technology, Tungsten, 010402 general chemistry, 021001 nanoscience & nanotechnology, Hot pressing, Microstructure, 01 natural sciences, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Fracture toughness, chemistry, Flexural strength, visual_art, Vickers hardness test, Materials Chemistry, Ceramics and Composites, visual_art.visual_art_medium, Ceramic, Composite material, 0210 nano-technology
Abstract

In this study, tungsten tetraboride (WB4) ceramics were synthesized in situ from powder mixtures of W and amorphous B with Ni as a sintering aid by reactive hot pressing method. The as-synthesized ceramics exhibited porosity as low as 0.375% and ultra-high Vickers hardness (Hv), as much as 49.808 ± 1.683 GPa (for the low load of 0.49 N). It was seen that the addition of Ni greatly improved the sinterability of WB4 ceramic. Besides, the flexural strength and fracture toughness of WB4 ceramic were measured for the first time to be 332.857 ± 36.763 MPa and 4.136 ± 0.259 MPa m1/2, respectively, suggesting that the ceramic has good mechanical properties. The effects of sintering temperature and holding time on the densification, Vickers hardness, and mechanical properties of WB4 ceramics were also investigated systematically as part of our study. The results indicated that increasing the sintering temperature can obviously improve the densification and mechanical properties of the ceramics. The bulk density and Vickers hardness of WB4 ceramic sintered at 1650 °C for 60 min under 30 MPa revealed the highest values of 6.366 g cm−3 and 27.948 ± 0.686 GPa (for the high load of 9.8 N), respectively. The flexural strength increased to the highest value of 332.857 ± 36.763 MPa for sintering temperature up to 1550 °C, but decreased slightly as the sintering temperature further increased to 1650 °C. On the other hand, the fracture toughness increased gradually with increasing temperature. It was also found that Vickers hardness showed a similar trend as the densification of the samples with increasing temperature and holding time. Besides, no obvious improvements in the densification, mechanical properties, and Vickers hardness of the samples with sintering time were observed in this study. The microstructure and fracture behaviours of the as-synthesized WB4 ceramic were also revealed, and the toughening mechanism has been discussed.

Published
2018

3. Effect of TiN concentration on microstructure and properties of Ni/W–TiN composites obtained by pulse current electrodeposition.

Author

Liu, Haijun, Wang, Hui, Yu, Weipeng, He, Yang, Xia, Fafeng, Ma, Chunyang, and Shakoor, Azar

Subjects
*ELECTROPLATING, *ATOMIC force microscopy, *MICROSTRUCTURE, *TIN, *MECHANICAL wear
Abstract

In this study, Ni/W–TiN composites were fabricated by the pulse current electrodeposition (PCE) method. The effects of TiN concentration on the microstructure, microhardness, and wear properties of the resulting composites were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), microhardness tester, and friction wear testing. Among the four obtained composites, Ni/W–TiN composite prepared at 8 g/L showed the densest and finest surface structure. The TiN contents in obtained Ni/W–TiN composites at 8 and 16 g/L were estimated to 8.1 and 5.4 wt%, respectively. The average Ni/W grain diameter in Ni/W–TiN composite obtained at 8 g/L TiN was recorded as 84.7 nm. The protrusion and depression heights of the composite deposited at 8 g/L were 81.8 and 45.4 nm, respectively. This composite also processed an average microhardness of 897.6 HV, with only a few shallow and narrow scratches on its worn surface, demonstrating its prominent wear resistance when compared to the other three composites. [ABSTRACT FROM AUTHOR]

Published
2021
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results