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Interference mechanism and damage accumulation in high-speed cross scratches on hard brittle materials

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Chinese Journal of Aeronautics 2022年第3期35卷 579-591页

作者： Feifei ZHAO Bin LIN Yuanping HE Tianyi SUI key laboratory of advanced ceramics and machining technology Ministry of EducationTianjin UniversityTianjin 300350China

Precision and low damage grinding of aviation optical elements can effectively improve the overall processing efficiency.The mechanism of high-speed cross scuffing of multiple abrasive particles has become an important factor affecting the forming quality of workpiece.Interaction of abrasive trajectory determines machined surface and subsurface morphology and damage.According to the relative motion trajectory of wear particles on the workpiece surface,a theoretical model of the trochoidal trajectory intersection angle is proposed.High-speed scratches with different cross angles are experimentally obtained to explore the interference mechanism and damage accumulation of cross scratches.The results indicate that the Crack system I and Crack system II,produced by the two cross scratches,are mainly based on the stress principle and the strength principle,respectively.An increase in the damage radius is observed with a decrease in the crossing angle.Furthermore,as the duration of the normal cutting force decomposition curve at the entrance/exit of the intersection increases,the half-peak width also increases.The accumulation of cross-scratch damage promotes the propagation of deep subsurface lateral and median cracks.In other words,damage accumulation and interference mechanism formed by the cross scratches increase the longitudinal depth and lateral length of the damage.

关键词： Cross angle Damage accumulation Damage radius Interference mechanism Trochoidal feed scratches

Dual-modification of manganese oxide by heterostructure and cation pre-intercalation for high-rate and stable zinc-ion storage

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Journal of Energy Chemistry 2022年第4期31卷 82-91页

作者： Song Wang Weibing Ma Zhiyuan Sang Feng Hou Wenping Si Jingdong Guo Ji Liang De'an Yang Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education School of Materials Science and EngineeringTianjin UniversityTianjin 300072China

Zinc-ion batteries(ZIBs)possess great advantages in terms of high safety and low cost,and are regarded as promising alternatives to lithium-ion batteries(LIBs).However,limited by the electrochemical kinetics and structural stability of the typical cathode materials,it is still difficult to simultaneously achieve high rates and high cycling stability for ZIBs.Herein,we present a manganese oxide(Sn_(x)Mn O_(2)/Sn O_(2))material that is dual-modified by Sn O_(2)/Mn O_(2)heterostructures and pre-intercalated Sn;cations as the cathode material for ZIBs.Such modification provides sufficient hetero-interfaces and expanded interlayer spacing in the material,which greatly facilitates the insertion/extraction of Zn^(2+).Meanwhile,the“structural pillars”of Sn^(4+) cations and the“pinning effect”of SnO_(2)also structurally stabilizes the Mn O_(2)species during the repeated Zn^(2+) insertion/extraction,leading to ultra-high cycling stability.Due to these merits,the Sn_(x)MnO_(2)/SnO_(2)cathode exhibits a high reversible capacity of 316.1 m Ah g^(-1) at 0.3 A g^(-1),superior rate capability of 179.4 m Ah g^(-1) at 2 A g^(-1),and 92.4%capacity retention after 2000 cycles.Consequently,this work would provide a promising yet efficient strategy by combining heterostructures and cations preintercalation to obtain high-performance cathodes for ZIBs.

关键词： Zinc-ion battery Manganese-based cathode material Pre-intercalation Heterostructure

New class of high-entropy pseudobrookite titanate with excellent thermal stability,low thermal expansion coefficient,and low thermal conductivity

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Journal of advanced ceramics 2022年第10期11卷 1654-1670页

作者： Jinyu WU Xiaohui MA Xiaoxia HU Liwen YAN Feng HOU Jiachen LIU Anran GUO School of Materials Science and Engineering Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of EducationTianjin UniversityTianjin 300072China

As a type of titanate,the pseudobrookite(MTi_(2)O_(5)/M_(2)TiO_(5))exhibits a low thermal expansion coefficient and thermal conductivity,as well as excellent dielectric and solar spectrum absorption properties.However,the pseudobrookite is unstable and prone to decomposing below 1200℃,which limits the practical application of the pseudobrookite.In this paper,the high-entropy pseudobrookite ceramic is synthesized for the first time.The pure high-entropy(Mg,Co,Ni,Zn)Ti_(2)O_(5) with the pseudobrookite structure and the biphasic high-entropy ceramic composed of the highentropy pseudobrookite(Cr,Mn,Fe,Al,Ga)_(2)TiO_(5) and the high-entropy spinel(Cr,Mn,Fe,Al,Ga,Ti)_(3)O_(4) are successfully prepared by the in-situ solid-phase reaction method.The comparison between the theoretical crystal structure of the pseudobrookite and the aberration-corrected scanning transmission electron microscopy(AC-STEM)images of high-entropy(Mg,Co,Ni,Zn)Ti_(2)O_(5) shows that the metal ions(M and Ti ions)are disorderly distributed at the A site and the B site in high-entropy(Mg,Co,Ni,Zn)Ti_(2)O_(5),leading to an unprecedentedly high configurational entropy of high-entropy(Mg,Co,Ni,Zn)Ti_(2)O_(5).The bulk high-entropy(Mg,Co,Ni,Zn)Ti_(2)O_(5) ceramics exhibit a low thermal expansion coefficient of 6.35×10^(−6) K^(−1) in the temperature range of 25-1400℃ and thermal conductivity of 1.840 W·m^(−1)·K^(−1) at room temperature,as well as the excellent thermal stability at 200,600,and 1400℃.Owing to these outstanding properties,high-entropy(Mg,Co,Ni,Zn)Ti_(2)O_(5) is expected to be the promising candidate for high-temperature thermal insulation.This work has further extended the family of different crystal structures of high-entropy ceramics reported to date.

关键词： high-entropy pseudobrookite (Mg,Co,Ni,Zn)Ti_(2)O_(5) (Cr,Mn,Fe,Al,Ga)_(2)TiO_(5) high conformational entropy thermal expansion coefficient thermal conductivity

Reversible Zn stripping/plating achieved by surface thin Sn layer for high-performance aqueous zinc metal batteries

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Journal of Materials Science & technology 2022年第22期117卷 72-78页

作者： Bingfeng Cui Yu Gao Xiaopeng Han Wenbin Hu Tianjin key laboratory of Composite and Functional Materials Key Laboratory of Advanced Ceramics and Machining Technology(Ministry of Education)School of Materials Science and EngineeringTianjin UniversityTianjin 300350China

Aqueous zinc metal batteries (ZMBs) are considered as the most promising candidate for large-scale energy storage system due to their abundant reserves and high safety. To achieve highly stable zinc metalbatteries, it is imperative to inhibit the unavoidable dendrite growth, which leads to the non-uniformzinc deposition and even makes the battery short circuit. Herein, Sn coating is loaded on copper foil(SCF) by a simple electrodeposition to guide the uniform zinc deposition, which not only lowers the zincnucleation overpotential but also promotes the uniform zinc deposition/dissolution. As a result, the Znplated SCF (Zn@SCF) anode presents a low voltage hysteresis of ∼40 mV and a superior stability over270 h in symmetric cells at a current density of 1 mA cm^(−2). Furthermore, the Zn@SCF anode can realizethe improved performance for full cells paired with α-MnO_(2) cathode. This work provides a simple andeffective approach to modify the Zn anode for improved electrochemical performance of ZMBs.

关键词： Tin coatings Uniform zinc deposition Zinc anode Zinc metal batteries

Fabrication of low-resistance LaNi_xO_(3+δ) thin films for ferroelectric device electrodes

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Journal of Rare Earths 2018年第8期36卷 838-843页

作者： Mi Xiao Zebin Zhang Weikang Zhang Ping Zhang Kuibo Lan School of Electrical and Information Engineering & Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education Tianjin University

LaNiO3 thin films with different La/Ni ratios were deposited on Si substrates by sol-gel process. The electrical resistivities of LaNixO3＋δfilms with different La/Ni ratios were measured by four-probe method.LaNi（0.95）O3＋δthin film has the lowest resistivity. First-principle calculations show that LaNi（0.95）O3＋δhas the largest Ni-O-Ni bond angle and the shortest Ni-O bond length, which means LaNi（0.95）O3＋δhas the strongest metallic property, hence, the electrical resistivity is the lowest. Au/PZT（PbZr（0.52）Ti（0.48）O3）/LaNixO3＋δand Au/PZT/Pt ferroelectric capacitors were fabricated to evaluate LaNixO3＋δas a bottom electrode. It is shown that fatigue properties of PZT films can be significantly improved by using LaNixO3＋δinstead of Pt as the bottom electrode. The Ⅰ-Ⅴ test results of PZT films show that LaNi（0.95）O3＋δas bottom electrode can reduce the threshold voltages of PZT films, suggesting that La/Ni ratio in LaNixO3＋δas a large influence on the film properties.

关键词： LaNiO3 Thin film Sol-gel Electrical property First-principle calculation Rare earths

Facile autoreduction synthesis of core-shell Bi-Bi2O3/CNT with 3-dimensional neural network structure for high-rate performance supercapacitor

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Journal of Materials Science & technology 2020年第12期47卷 169-176页

作者： Han Wu Jingdong Guo De'an Yang Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education School of Materials Science and EngineeringTianjin University300072China

Core-shell Bi-Bi2 O3/CNT(carbon nanotube) with 3-dimensional neural network structure where Bi-Bi2O3 nanospheres act as cell bodies supported by a 3-dimensional network of CNTs acting as synapses is designed and prepared by simple solvothermal method and subsequent annealing autoreduction treatment,and this structure facilitates the efficient transport of electrons.It can provide two electron transfer paths due to the double contact of Bi2O3 shell with CNT and metal Bi core which enhances the efficiency of the electrochemical reaction.The Bi-Bi2 O3/CNT electrode shows a high gravimetric capacitance of 850 F g-1(1 A g-1),and the specific capacitance of Bi-Bi2O3/CNT can be still 714 F g-1 at 30 A g-1 indicating excellent rate performance.The asymmetric supercapacitor is assembled with Bi-Bi2 O3/CNT as the negative electrode and Ni(OH)2/CNT as the positive electrode,delivering a high energy density of 36.7 Wh kg-1 and a maximum power density of 8000 W kg-1.Therefore,the core-shell Bi-Bi2O3/CNT with 3-dimensional neural network structure as the negative electrode of supercapacitor shows great potential in the field of energy storage in the future.

关键词： Electrochemical energy-storage Asymmetric supercapacitor 3-Dimensional neural network structure Core-shell structure Bismuth oxide Bismuth metal Carbon nanotube

Evaluating the Stability of Active Manganese Sites During Electrochemical Reactions by Cyclic Voltammetry

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Transactions of Tianjin University 2022年第3期28卷 193-198页

作者： Ziang Ma Jisi Li Tao Ling key laboratory for advanced ceramics and machining technology of ministry of education TianjinChina key laboratory of Composite and Functional Materials School of Materials Science and EngineeringTianjin UniversityTianjin 300072China

Manganese oxides are a promising class of electrocatalysts for renewable energy devices,such as fuel cells.Mn(Ⅲ) ions with e_(g) electron filling of-1 are the active sites for manganese-based electrocatalysts.However,Mn(Ⅲ) sites may be disproportionated during electrochemical reactions,thus reducing the number of Mn(Ⅲ) active sites and decreasing the catalytic activity of manganese oxides.In this work,we developed a facile cyclic voltammetry method to monitor the evolution of Mn(Ⅲ) sites on a series of manganese oxides under "working" conditions.We proposed a descriptor S_(Mn(Ⅲ)) to describe the stability of Mn(Ⅲ).Our simulated and experimental results show that the higher is S_(Mn(Ⅲ)),the higher the active Mn(Ⅲ)density,and the higher the electrocatalytic activity of the manganese oxide electrocatalyst.

关键词： Manganese oxides Mn(III)sites Cyclic voltammetry

Aqueous lubrication and surface microstructures of engineering polymer materials (PEEK and PI) when sliding against Si3N4

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Friction 2017年第4期5卷 414-428页

作者： Anying WANG Shuai YAN Bin LIN Xiaofeng ZHANG Xiaoxue ZHOU Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education Tianjin UniversityTianjin 300350China

Polyether-ether-ketone (PEEK) and polyimide (PI) are two kinds of engineering polymer materials widely used as roller bearing cages and rings under extreme environment because of their noise reduction and corrosion resistance properties. The Si3N4 ceramic is the most common ball bearing material. Many current engineering applications of ball bearings require aqueous lubrication. Therefore, this study presents the aqueous lubrication of tribopairs formed by PEEK and PI material sliding against Si3N4 ceramic. Experimental results show that two tribopairs exhibited the similar tribological properties under the dry condition. Water as a lubricant for the PI–Si3N4 tribopair pairs effectively reduces both friction coefficients by 35.5% and wear rates by 32%. The water absorption of PI induces better tribological properties by changing the tribopair surface properties. In addition, the dimples appearing on the PI tribopair surface under water generate additional hydrodynamic lubrication and further improve the friction properties of surface. The PEEK–Si3N4 tribopair shows similar friction coefficients under two kinds of environments. The wear rates under water are approximately more than two times of that under dry sliding. However, water inhibits the appearance of the crush phenomenon and enhances the carrying capacity of the tribopair. Energy dispersive spectroscopy and X-ray diffraction spectra demonstrate no chemical corrosion. The 3D profiler and SEM morphologies illustrate that the transfer film would be formed from the surface of PEEK under water but hindered under dry friction. Overall, the PI–Si3N4 tribopair exhibits better properties than PEEK under water and is promising for future applications in the bearing industry.

关键词： PEEK PI aqueous lubrication dry friction tribological properties ceramic bearing

Flower-like CuS/graphene oxide with photothermal and enhanced photocatalytic effect for rapid bacteria-killing using visible light

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Rare Metals 2022年第2期41卷 639-649页

作者： Rui Lv Yan-Qin Liang Zhao-Yang Li Sheng-Li Zhu Zhen-Duo Cui Shui-LinWu School of Materials Science&Engineering the Key Laboratory of Advanced Ceramics and Machining Technology by the Ministry of Education of ChinaTianjin UniversityTianjin 300072China The key laboratory of advanced ceramics and machining technology by the ministry of education of China Tianjin UniversityTianjin 300072China

Pathogenic bacteria have been threatening the daily life of human beings.More effective methods without causing drug-resistance of bacteria need to be developed to fight against these pathogens.Herein,flower-like CuS/-graphene oxide(GO)hybrids have been successfully synthesized via simple one-pot hydrothermal process.GO worked as an excellent electron acceptor to transport the photogenerated electrons from CuS,which can suppress the recombination of hole–electron pairs efficiently,thus enhancing the photocatalytic property.In addition,the morphology of CuS and GO with high specific surface area and the increased defect in GO also improved photocatalytic performance of the hybrid.Owing to the synergy of photothermal,enhanced photocatalytic effect and released Cu ions,CuS/GO exhibited outstanding antibacterial efficacy under visible light irradiation for 15 min.Additionally,the hybrid showed great biocompatibility to L929 cell.Hence,the synthesized CuS/GO would be a promising antibacterial material for daily life including rapid water disinfection and wounds sterilization.

关键词： Antibacterial Photocatalytic CuS Graphene oxide Photoresponsive