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33 results on '"Kang, Yonghai"'

13. Preparation of an environmentally friendly antifouling degradable polyurethane coating material based on medium-length fluorinated diols

Author

Meilong Chen, Liu Huiyang, Guo Yan, Baoli Ou, Guo Yuanjun, Kang Yonghai, Jianhui Yan, and Li Tian

Subjects
Thermogravimetric analysis, Materials science, Polymers and Plastics, 02 engineering and technology, General Chemistry, Biodegradation, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Surface energy, 0104 chemical sciences, Contact angle, chemistry.chemical_compound, Chemical engineering, chemistry, Polymerization, Materials Chemistry, Ceramics and Composites, Thermal stability, Fourier transform infrared spectroscopy, 0210 nano-technology, Polyurethane
Abstract

A novel medium-length fluorinated diols and poly(L-lactide) (PLLA) were synthesized via Michael addition reaction and ring-opening polymerization, respectively. Subsequently, Synthetic medium-length fluorinated diols and PLLA were combined to prepare new polyurethane composites with degradability and low surface energy. The compositional analysis and structural characterization of synthetic materials were characterized by using fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectra (1HNMR). Thermogravimetric analysis(TGA) indicated that the introduction of medium-length fluorinated diols improved the thermal stability of the polyurethane. The biodegradation and low surface energy of the polyurethane were investigated by static hydrolysis experiment and water contact angle test. It was found that the degradation rate of the polyurethane increased as measurement time went on when the PLLA content was under 40%, and the water contact angle increased from 71.12° ...

Published
2018

14. Preparation of novel marine antifouling polyurethane coating materials

Author

Guo Yuanjun, Meilong Chen, Kang Yonghai, Jianhui Yan, Qingquan Liu, Guo Yan, Duxin Li, Shanggao Zhang, and Ou Baoli

Subjects
Condensation polymer, Materials science, Polymers and Plastics, Polydimethylsiloxane, Graphene, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, 0104 chemical sciences, law.invention, Contact angle, chemistry.chemical_compound, chemistry, Chemical engineering, Polymerization, law, Materials Chemistry, Fourier transform infrared spectroscopy, 0210 nano-technology, Prepolymer, Polyurethane
Abstract

Polyurethane coating materials with different compositions of low surface energy polydimethylsiloxane and degradable poly(l-lactic acid) were synthesized by three major steps. Initially, the hydroxylation-terminated poly(l-lactide)-functionalized graphene (G-g-PLLA) was prepared by ring-opening polymerization of l-lactic acid using the phenol-functionalized graphene (G-f-OH), which was prepared by 1,3-dipolar cycloaddition reaction of graphene and 3,4-dihydroxybenzaldehyde when N-methylglycine and tin octoate were used as initiator and catalyst, respectively. Subsequently, isocyanate-terminated polyurethane prepolymer with polydimethylsiloxane was obtained by condensation polymerization of polydimethylsiloxane and isocyanate-terminated polyurethane prepolymer that was obtained by the condensation polymerization of 4,4′-diphenylmethane diisocyanate and 1,4-butane diol. Finally, the novel polyurethane coating materials were prepared by the condensation polymerization of G-g-PLLA and isocyanate-terminated polyurethane prepolymer with polydimethylsiloxane. These synthesized materials were carefully analyzed with Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectra (1H NMR), field-emission scanning electron microscopy (SEM), and high-resolution transmission (TEM). In addition, the water contact angles were measured. It was found that the surface free energy of the polyurethane coating materials decreased from 52.19 to 11.74 N/m2 with the increase of polydimethylsiloxane content from 0 to 20% and the water contact angle of the polyurethane coating materials increased from 71° to 108°. Moreover, the mechanical property was investigated. The studies also demonstrated that functionalized polyurethane was able to hydrolyze in seawater and the hydrolysis rate decreased as the PDMS content increased. At the same time, simulative ocean hanging plate experiment confirmed that the novel polyurethane coating materials exhibited a good antifouling performance, which indicated that the functionalized polyurethane has a potentiality in marine antifouling coating application.

Published
2018

22. Tribological Properties of NiAl Matrix Composite Sliding Against SiN, SiC and AlO at Elevated Temperatures.

Author

Yan, Chengqi, Kang, Yonghai, Kong, Lingqian, and Zhu, Shengyu

Subjects
NICKEL-aluminum alloys, TRIBOLOGY, SLIDING friction, SILICON nitride, HIGH temperatures, SILICON carbide, ALUMINUM oxide, LUBRICATION & lubricants
Abstract

The NiAl matrix self-lubricating composite was fabricated by powder metallurgy technique. The tribological behavior of the composite sliding against commercial SiN, SiC and AlO ceramic balls was investigated from 20 to 1000 °C. It was found that the composite demonstrated excellent lubricating properties with different friction pairs at a wide temperature range, which can be attributed to the synergetic effect of Ag, fluorides, and molybdates formed by oxidations. The NiAl matrix self-lubricating composite/SiN couple possessed the stable friction coefficient and wear rate. [ABSTRACT FROM AUTHOR]

Published
2017
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24. Friction and wear behavior of nanoeutectic Fe1.87C0.13 under air and vacuum conditions.

Author

Li, Fei, Kang, Yonghai, Fu, Licai, Qiao, Zhuhui, Liu, Weimin, and Yang, Jun

Abstract

In this paper, the tribological behavior of nanoeutectic Fe1.87C0.13 alloy and its coarse-grained-eutectic counterpart under air and vacuum was investigated. The results showed that the wear rate of both alloys was lower in air than in vacuum, and their friction coefficient was related to applied load and testing atmosphere. The nanoeutectic Fe1.87C0.13 alloy exhibited lower wear rate than the coarse grained counterpart in both environments. The wear rate of both alloys increased but the friction coefficient decreased with increasing applied load under both air and vacuum. The dominant wear mechanisms were adhesion wear in vacuum but oxidation wear along with slight delamination in air. [ABSTRACT FROM AUTHOR]

Published
2016
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28. Friction and wear behavior of nanoeutectic Fe1.87C0.13under air and vacuum conditions

Author

Li, Fei, Kang, Yonghai, Fu, Licai, Qiao, Zhuhui, Liu, Weimin, and Yang, Jun

Abstract

In this paper, the tribological behavior of nanoeutectic Fe1.87C0.13alloy and its coarse-grained-eutectic counterpart under air and vacuum was investigated. The results showed that the wear rate of both alloys was lower in air than in vacuum, and their friction coefficient was related to applied load and testing atmosphere. The nanoeutectic Fe1.87C0.13alloy exhibited lower wear rate than the coarse grained counterpart in both environments. The wear rate of both alloys increased but the friction coefficient decreased with increasing applied load under both air and vacuum. The dominant wear mechanisms were adhesion wear in vacuum but oxidation wear along with slight delamination in air.

Published
2016
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29. Strengthening of a high strength Fe85Ni15 alloy by tempering treatment.

Author

Kang, Yonghai, Fu, Licai, Ma, Jiqiang, Li, Fei, Qiao, Zhuhui, Yang, Jun, Bi, Qinling, and Liu, Weimin

Subjects
*IRON alloys, *HEAT treatment of metals, *MARTENSITIC structure, *METAL hardness, *METALS, *DUCTILITY, *STRENGTH of materials, *COMPRESSION loads, *MARTENSITIC transformations
Abstract

Abstract: A high-strength Fe85Ni15 alloy with lath martensitic structure was obtained by the self-propagating high-temperature synthesis technique. After tempering at 500°C for 2h, the hardness increased from 3.8 to 5.1GPa, and the compression yield strength increased from about 1100 to 1500MPa without much sacrifice of ductility. The strengthening effect might be attributed to the evolution of lath martensitic morphology and the reverse martensitic transformation. [Copyright &y& Elsevier]

Published
2013
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30. Tribological behavior of Fe70Ni30 alloy with nanoscale twins under liquid paraffin lubrication.

Author

Kang, Yonghai, Yang, Jun, Fu, Licai, Ma, Jiqiang, Bi, Qinling, and Liu, Weimin

Subjects
IRON-nickel alloys, NANOSTRUCTURED materials, PARAFFIN wax, NITROGEN, LUBRICATION & lubricants, FRICTION
Abstract

Fe70Ni30 alloy with nanoscale twins was obtained by deep cryogenic treatment (DCT) of coarse grained Fe70Ni30 alloy (CG-Fe70Ni30) at liquid nitrogen temperature. The tribological behavior of DCT-Fe70Ni30 alloy was investigated under liquid paraffin oil lubrication compared with that of CG-Fe70Ni30 alloy. The experimental results showed that the wear resistance of DCT-Fe70Ni30 alloy was improved significantly after the introduction of nanoscale twins, and DCT-Fe70Ni30 alloy also showed a little lower friction coefficient relative to CG-Fe70Ni30 alloy. The results indicated that twins play a positive role in the material's friction-reduction and anti-wear properties, which is attributed to the better oil-adsorption ability and enhanced hardness of DCT-Fe70Ni30 alloy caused by structural refinement. Wear mechanisms were discussed. [ABSTRACT FROM AUTHOR]

Published
2013
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31. Mechanical properties and dry-sliding tribological behavior of partially twinned Fe70Ni30 alloy

Author

Kang, Yonghai, Yang, Jun, Fu, Licai, Bi, Qinling, and Liu, Weimin

Subjects
*TRIBOLOGY, *SLIDING friction, *MECHANICAL properties of metals, *IRON-nickel alloys, *MARTENSITE, *MECHANICAL wear, *THIN films
Abstract

Abstract: The mechanical properties and wear behavior of an Fe70Ni30 alloy with twinned martensite structure obtained by deep cryogenic treatment at −196°c (DCT) were evaluated in comparison with that of coarse-grained (CG) Fe70Ni30 alloy (single austenite phase). The results showed that after the introduction of martensite with nano-scale twins, the Vickers hardness of Fe70Ni30 increased from 145 to 248Hv. The friction coefficient of both samples was almost the same, and it decreased with increasing applied load and increased with increasing sliding speed. The XPS results indicated that oxide protecting film was formed on the worn surface, which may dominate the friction coefficient. The wear rate for both samples increased with increasing applied load and decreased slightly with increasing sliding speed. The wear resistance of DCT-Fe70Ni30 alloy was obviously enhanced. The wear mechanisms were investigated by SEM accordingly. [Copyright &y& Elsevier]

Published
2012
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32. Tribological behavior of Fe3Al-60 wt.% Fe3AlC0.5composite under air and vacuum conditions

Author

Kang, Yonghai, Hao, Junying, Qiao, Zhuhui, Fu, Licai, Liu, Weimin, and Yang, Jun

Abstract

The tribological behavior of Fe3Al composite with 60 wt.% Fe3AlC0.5under air and vacuum was studied. The composite exhibited a lower wear rate but somewhat higher friction coefficient under air than vacuum. The wear rates increased and the friction coefficients decreased with increasing the applied load under both conditions. The sub-layer of the worn surface under vacuum suffered from severe plastic deformation. This was not the case under air due to protection by surface oxide films. The dominant wear mechanisms were plastic deformation and adhesion under vacuum and oxidative wear and slight delamination under air.

Published
2014
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33. Tribological behavior of Fe70Ni30alloy with nanoscale twins under liquid paraffin lubrication

Author

Kang, Yonghai, Yang, Jun, Fu, Licai, Ma, Jiqiang, Bi, Qinling, and Liu, Weimin

Abstract

Fe70Ni30alloy with nanoscale twins was obtained by deep cryogenic treatment (DCT) of coarse grained Fe70Ni30alloy (CG-Fe70Ni30) at liquid nitrogen temperature. The tribological behavior of DCT-Fe70Ni30alloy was investigated under liquid paraffin oil lubrication compared with that of CG-Fe70Ni30alloy. The experimental results showed that the wear resistance of DCT-Fe70Ni30alloy was improved significantly after the introduction of nanoscale twins, and DCT-Fe70Ni30alloy also showed a little lower friction coefficient relative to CG-Fe70Ni30alloy. The results indicated that twins play a positive role in the material's friction-reduction and anti-wear properties, which is attributed to the better oil-adsorption ability and enhanced hardness of DCT-Fe70Ni30alloy caused by structural refinement. Wear mechanisms were discussed.

Published
2013
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