Lithiated Nafion-garnet ceramic composite electrolyte membrane for solid-state lithium metal battery

Single-ion conducting solid polymer electrolytes are expected to play a vital role in the realization of solid-state Li metal batteries.In this work,a lithiated Nafion(Li-Nafion)-garnet ceramic Li6.25La3 Zr2 Al0.25O12(LLZAO)composite solid electrolyte(CSE)membrane with 30μm thickness was prepared for the first time.By employing X-ray photoelectron spectroscopy and transmission electron microscope,the interaction between LLZAO and Li-Nafion was investigated.It is found that the LLZAO interacts with the Li-Nafion to form a space charge layer at the interface between LLZAO and Li-Nafion.The space charge layer reduces the migration barrier of Li-ions and improves the ionic conductivity of the CSE membrane.The CSE membrane containing 10 wt%LLZAO exhibits the highest ionic conductivity of2.26×10-4 S cm-1 at 30℃among the pristine Li-Nafion membrane,the membrane containing 5 wt%,20 wt%,and 30 wt%LLZAO,respectively.It also exhibits a high Li-ion transference number of 0.92,and a broader electrochemical window of 0-+4.8 V vs.Li+/Li than that of 0-+4.0 V vs.Li+/Li for the pristine Li-Nafion membrane.It is observed that the CSE membrane not only inhibits the growth of Li dendrites but also keeps excellent electrochemical stability with the Li electrode.Benefitting from the above merits,the solid-state LiFePO4/Li cell fabricated with the CSE membrane was practically charged and discharged at 30℃.The cell exhibits an initial reversible discharge specific capacity of 160 mAh g-1 with 97%capacity retention after 100 cycles at 0.2 C,and maintains discharge specific capacity of 126 mAh g-1 after500 cycles at 1 C.The CSE membrane prepared with Li-Nafion and LLZAO is proved to be a promising solid electrolyte for advanced solid-state Li metal batteries.

Vacuum brazing of Si/SiC ceramic composite and Invar alloy using TiSOCu-W filler metals

Si/SiC ceramic composite and lnvar alloy were successfidly joined by vacuum brazing using Ti5OCu-W filler metals into which W was added to release the thermal stress of the brazed joint. Microstructures of the brazed joints were irwestigated by scanning electron micrascope （SEM） and energy dispersive spectrometer （EDS）. The mechanical properties of the brazed joints were measured by shearing tests. The results showed that the brazed joints were composed of Ti-Cu phase, W phase and Ti-Si phase. W had no effect on the wettability and mobility of the .filler metals. The growth of Ti2 Cu phase was restrained, and the reaction between ceramic composite and filler metals was weakened. The specimen, brazed at 970°C for 5 rain, had the maximum shear strength of 108 MPa at room temperature.

Coarse WC Particles Ceramic-Metal Composite Coating by Laser Cladding

The coarse WC particles ceramic-metal com- posite coatings with WC density of 67 wt-% and thickness of 1.0-1.2 mm have been cladded on 20Ni4Mo steel surface by a 2 kW CO_2 laser.The sintered WC particles with the size of 600-1000 μm are chosen as the main strengthening phase, Ni-base self-flux alloy as the binder in the compo- site coatings.The microstructure and microhardness of both WC particles and binder are analysed.The rigid ball indention with acoustic emission technique is used to evaluate the brittleness of the coating.Finally,the abrasive wear resistance of the coating is tested.Besides,the coatings with the same ratio and size of WC parti- cles in low carbon steel tube rod were cladded on 20Ni4Mo steel by atomic hydrogen welding tech- nique and analysed by the same way,their results are compared.

Identification of Growth Promoter to Fabrication SiCp/Al₂O₃Ceramic Matrix Composites Prepared by Directed Metal Oxidation of An Al Alloy

SiC particulates reinforced alumina matrix composites were fabricated using Directed Metal Oxidation (DIMOX) process. Continuous oxidation of an Al-Si-Mg-Zn alloy with different interlayers (dopents) as growth promoters, will encompasses the early heating of the alloy ingot, melting and continued heating to temperature in the narrow range of 950°C to 980°C in an atmosphere of oxygen. Varying interlayers (dopents) are incorporated to examine the growth conditions of the composite materials and to identification of suitable growth promoter. The process is extremely difficult because molten aluminum does not oxidize after prolonged duration at high temperatures due to the formation of a passivating oxide layer. It is known that the Lanxide Corporation had used a combination of dopents to cause the growth of alumina from molten metal. This growth was directed, i.e. the growth is allowed only in the required direction and restricted in the other directions. The react nature of the dopants was a trade secret. Though it is roughly known that Mg and Si in the Al melt can aid growth, additional dopents used, the temperatures at which the process was carried out, the experimental configurations that aided directed growth were not precisely known. In this paper we have evaluated the conditions in which composites can be grown in large enough sizes for evaluation application and have arrived at a procedure that enables the fabrication of large composite samples by determining the suitable growth promoter (dopant). Scanning electron microscopic, EDS analysis of the composite was found to contain a continuous network of Al2O3, which was predominantly free of grain-boundary phases, a continuous network of Al alloy. Fabrication of large enough samples was done only by the inventor company and the property measurements by the company were confirmed to those needed to enable immediate applications. Since there are a large number of variable affecting robust growth of the composite, fabrication large sized samples for measurements is a difficult task. In the present work, to identify a suitable window of parameters that enables robust growth of the composite has been attempted.

Metal-Ceramic Smart Composite in Ti(C,N)-Ni-Mo-W System

Goal: Low wolfram-containing cutting composite was obtained by fusion of titanium carbonitride and high melting temperature binding metallic phase. Method: The composite was obtained via compaction and further sintering in vacuum furnace at 1600°C under 10-3 Pa pressure. Phase analysis was performed on X-ray apparatus “DRON-3”;microstructure was determined by electron microscope NANOLAB-7, microhardness by MUCKE-mark microhardness meter;relative resistance of cutters was evaluated at similar modes of cutting according to distances they passed;experiments were carried out on turning lathe. Results: Physical-mechanical characteristics of the obtained composite are: σbend, = 1000 - 1150 MPa, σbend1000°C = 600 MPa, HV = 14 GPa;HV1000°C = 6.5 GPa. High speeds of cutting and high temperatures resistance of cutters made by the obtained composites exceeds 1.5 - 2-folds that of cutters made of the known BK8 and KNT20 hard alloys. Conclusion: Its application is recommended in hot steel treatment by cutting, for removal of the so-called burrs, as well as in steel treatment by cutting during pure and semi-pure operations. It can also be used in jet engines, chemical industry apparatuses, electric-vacuum devices, in industry of responsible details of rockets, nuclear reactors, flying apparatuses.

Mechanical Behaviors of ZrO_2-Al_2O_3 Ceramic Composites with Y_2O_3 as Stabilizer

The ZrO2-Al2O3 ceramic composites were prepared by appropriate techniques with commercial ZrO2 and Al2O3 powders as raw materials and Y2O3 as stabilizer. The results indicate that with the introduction of Al2O3 into the ZrO2 matrix where the quantity of additive Y2O3 is 3.5% (mole fraction), the growth of ZrO2 grains is efficiently inhibited, which helps the ZrO2 grains exist in a metastable tetragonal manner; thus higher strength and toughness are acquired. When the content of alumina is 20% (mass fraction), the bending strength and fracture toughness of the composites are 676.7 MPa and 10 MPa·m1/2 respectively, the mechanical behaviors are close to those prepared with ZrO2 and Al2O3 powders synthesized through wet chemical approach. The mechanical behaviors of the composites are well improved owing to the dispersion toughening of alumina grains and phase transformation toughening of zirconia grains.

Modeling mechanical behaviors of composites with various ratios of matrixeinclusion properties using movable cellular automaton method

Two classes of composite materials are considered: classical metaleceramic composites with reinforcing hard inclusions as well as hard ceramics matrix with soft gel inclusions. Movable cellular automaton method is used for modeling the mechanical behaviors of such different heterogeneous materials. The method is based on particle approach and may be considered as a kind of discrete element method. The main feature of the method is the use of many-body forces of inter-element interaction within the formalism of simply deformable element approximation. It was shown that the strength of reinforcing particles and the width of particle-binder interphase boundaries had determining influence on the service characteristics of metaleceramic composite. In particular, the increasing of strength of carbide inclusions may lead to significant increase in the strength and ultimate strain of composite material. On the example of porous zirconia ceramics it was shown that the change in the mechanical properties of pore surface leads to the corresponding change in effective elastic modulus and strength limit of the ceramic sample. The less is the pore size, the more is this effect. The increase in the elastic properties of pore surface of ceramics may reduce its fracture energy.

INTERFACIAL REACTION BEHAVIOUR AND JOINT STRENGTH OF TiC_p/Si_3N_4 COMPOSITE BONDED WITH Al FOIL

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A Research on the Joining of SiC Composite to 40 Cr Steel

SiC composites and 40 Cr Steels were joined with Ag-Cu-Ti solder in order to develop a new method of joining ceramics to metal. Effects of solder component and process parameters on the joining strength were investigated. The results show that some chemical reactions occur on the jointing interface between ceramics and metal. Higher joining strength is achieved when titanium is 0.2% (mass fraction) in the solder. The thickness of solder also affects the joining characteristics, and 0.2-0.3 mm. thickness of solder is the most suitable.

Joining mechanism of field-assisted diffusion bonding of solid electrolyte ceramic to metals

Field assisted diffusion bonding applied in the joining of solid electrolyte borosilicate glass, β ″ Al 2O 3, Y 2O ZrO 2 to monocrystal silicate and aluminum were proceeded with bonding machine in the assistance of static electric field. TEM, SEM, XRD and other means were applied to investigate and analyze microstructure of interface. It is supposed that the interfacial area is a model of metal oxides ceramic, and the joining mechanism is solid diffusion joining and static electric bonding. The process of ions migration and accumulation under electric field is the most essential factor for the anodic oxidation and interfacial joining. Temperature and voltage are the basic factors of the solid diffusion bonding of interfacial oxidation. And voltage, temperature, pressure and the condition of surface are the most important factors that govern the bonding process.

3D core-shell nanofibers framework and functional ceramic nanoparticles synergistically reinforced composite polymer electrolytes for high-performance all-solid-state lithium metal battery

Satisfactory ionic conductivity,excellent mechanical stability,and high-temperature resistance are the prerequisites for the safe application of solid polymer electrolytes(SPEs)in all-solid-state lithium metal batteries(ASSLMBs).In this study,a novel poly(m-phenylene isophthalamide)(PMIA)-core/poly(ethylene oxide)(PEO)-shell nanofiber membrane and the functional Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)ceramic nanopar-ticle are simultaneously introduced into the PEO-based SPEs to prepare composite polymer electrolytes(CPEs).The core PMIA layer of composite nanofibers can greatly improve the mechanical strength and thermal stability of the CPEs,while the shell PEO layer can provide the 3D continuous transport channels for lithium ions.In addition,the introduction of functional LLZTO nanoparticle not only reduces the crys-tallinity of PEO,but also promotes the dissociation of lithium salts and releases more Li^(+)ions through its interaction with the Lewis acid-base of anions,thereby overall improving the transport of lithium ions.Consequently,the optimized CPEs present high ionic conductivity of 1.38×10^(−4)S/cm at 30℃,signifi-cantly improved mechanical strength(8.5 MPa),remarkable thermal stability(without obvious shrinkage at 150℃),and conspicuous Li dendrites blocking ability(>1800 h).The CPEs also both have good com-patibility and cyclic stability with LiFePO_(4)(>2000 cycles)and high-voltage LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811)(>500 cycles)cathodes.In addition,even at low temperature(40℃),the assembled LiFePO4/CPEs/Li bat-tery still can cycle stably.The novel design can provide an effective way to exploit high-performance solid-state electrolytes.

Study on the performance of thin-film VCSELs on composite metal substrate

Thin film p-side up vertical-cavity surface-emitting lasers(VCSELs)with 940 nm wavelength on a composite metal(Copper/Invar/Copper;CIC)substrate has been demonstrated by twice-bonding transfer and substrate removing techniques.The CIC substrate is a sandwich structure with a 10µm thick Copper(Cu)layer/30µm thick Invar layer/10µm thick Cu layer.The Invar layer was composed of Iron(Fe)and Nickel(Ni)with a proportion of 70:30.The thermal expansion coefcient of the composite CIC metal can match that of the GaAs substrate.It results that the VCSEL layers can be successfully transferred to CIC metal substrate without cracking.At 1 mA current,the top-emitting VCSEL/GaAs and thin-flm VCSEL/CIC had a voltage of 1.39 and 1.37 V,respectively.The optical output powers of VCSEL/GaAs and VCSEL/CIC were 21.91 and 24.40 mW,respectively.The 50µm thick CIC substrate can play a good heat dissipation function,which results in improving the electrical and optical characteristics of thin flm VCSELs/CIC.The VCSEL/CIC exhibited a superior thermal management capability as compared with VCSEL/GaAs.The obtained data suggested that VCSELs on a composite metal substrate not only afected signifcantly the characteristics of thin film VCSEL,but also improved considerably the device thermal performance.

流延法制备Metal/Al_2O_3复合基板及其导热性能

采用流延法制备Metal(Al,Mo,Ni)/Al_2O_3复合基板,优化了流延成型工艺,表征了不同复合基板的相组成、致密度和热导率,并对其导热机理进行讨论。结果表明:固含量为60%时浆料流动性较好,基板的相对密度高。经1550℃烧结后复合基板中的金属相均发生了不同程度的氧化,其中Ni/Al_2O_3复合基板的抗氧化性能最好,其相对密度在95%以上,热导率为29.1 W/(m·K),有望作为散热基板应用于LED组件中。

A bulk metal/ceramic composite material with a cellular structure

A bulk metal/ceramic composite material with a honeycomb-like micro-cell structure has been prepared by sintering the spherical Al90Mn9Ce1 alloy powders clad by Al2O3 nano-powder with the spark plasma sintering (SPS) technique. The as-prepared material consists of Al90Mn9Ce1 alloy cell and closed Al2O3 ceramic cell wall. The diameter of the cells is about 20―40 μm, while a thickness of the cell wall is about 1―2 μm. The ultimate compressive strength of the as-sintered materials is about 514 MPa, while its fracture strain is up to about 0.65 %. This composite material might possess good anti-corrosion, thermal endurance and other potential properties due to its unique microstructure. The result shows that the Al90Mn9Ce1/Al2O3 composite powders can be sintered by spark plasma sintering technique despite the large difference in their sintering temperature. This work offers a way of designing and preparing metal/ceramic composite material with functional property.

Interaction between AE44 magnesium alloy and SiC-Al_2O_3-SiO_2 ceramic foam

The interaction between a molten magnesium alloy AE44 and a SiC?Al2O3?SiO2 ceramics and the resulting reaction products were studied. The samples were investigated using optical and electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. SiO2was predominantly reduced by Mg during the contact of the magnesium-rich melt with the ceramics. The main reaction product was MgO, whilst Si dissolved in the melt. Two novel tetragonal phases formed at the interface: AlSiRE and AlMgSiRE, having a specific mutual crystallographic orientation relationship. The interactions resulted in strongly connected interfaces between the metal and ceramics after short interaction time; however, interactions lead to disintegration of the ceramics after longer contact time.

Influence of Features of Interphase Boundaries on Mechanical Properties and Fracture Pattern in Metal-Ceramic Composites

The results of a theoretical study on the influence of strength of interphase boundaries in metal-ceramic composite on macroscopical characteristics of composite response such as strength, deformation capacity, fracture energy and fracture pattern are presented. The study was conducted by means of computer-aided simulation by means of movable cellular automaton method taking account of a developed ＂mesoscopical＂ structural model of particle-reinforced composite. The strength of interphase boundaries is found to be a key structural factor determining not only the strength properties of metal-ceramic composite, but also the pattern and rate of fracture. The principles for achievement of the high-strength values of particle/binder interfaces in the metal-ceramic composition due to the formation of the wide transition zones （areas of variable chemical composition） at the interphase boundaries are discussed. Simulation results confirm that such transition zones provide a change in fracture mechanism and make the achievement of a high-strength and a high deformation capacity of metal-ceramic composite possible.

Application of Ag-Cu-Ti active metal composite filler in ceramic joining:a review

As a structural and functional material with excellent properties,ceramics play an extremely important role in a wide range of industries,including life and production.To expand the range of applications for ceramic materials,ceramics are often joined to metals and then used.Among the physical and chemical joining methods of ceramics to metals,the AMB method is efficient and simple,suitable for industrial applications,and has been a hot topic of research.However,due to the problems of residual stresses caused by the large difference in thermal expansion coefficients between ceramic and metal brazing,composite fillers have become a very worthwhile solution by regulating the physical properties of the brazing material and improving the weld structure.This review describes the wetting principle and application of Ag‒Cu‒Ti active metal filler in the field of ceramic joining,with emphasis on the current stage of composite filler,and discusses the influence on the former brazing properties and organization after the introduction of dissimilar materials.

MIL-100(Fe)光芬顿催化剂的制备与循环使用研究

为解决金属有机框架MIL-100(Fe)粉末在实际工业应用中难以回收重复利用的难题,采用水热法合成了MIL-100(Fe)粉末,利用真空抽滤法将其负载到氧化铝多孔陶瓷片上,制备了MIL-100(Fe)@多孔陶瓷复合材料。利用场发射扫描电子显微镜能谱联用仪(FE-SEM-EDS)、X射线衍射仪(XRD)、比表面积分析仪(BET)、紫外可见光分光光度计(UV-VIS)等仪器对MIL-100(Fe)及复合材料的结构与性能进行了表征;以罗丹明B(RhB)溶液模拟染料废水,研究了在MIL-100(Fe)在H_(2)O_(2)反应体系中对染料的光芬顿降解能力。结果表明,MIL-100(Fe)呈现八面体结构,比表面积高达1152.75 m^(2)/g,当反应温度为60℃、H_(2)O_(2)的初始浓度为0.5 g/L、RhB溶液的初始浓度为20 mg/L时,RhB溶液的降解率达到99.26%。MIL-100(Fe)@多孔陶瓷在循环使用5次时,对RhB溶液的降解率仍达到98%以上,循环使用稳定性良好,具有商业化应用前景。

氮化硅陶瓷基板制备及其金属化研究

低成本制备Si_(3)N_(4)陶瓷基板及其金属化是Si_(3)N_(4)陶瓷在电子行业应用中面临的关键问题。对Si_(3)N_(4)陶瓷流延成型配方体系进行了研究,系统分析了分散剂、黏结剂、增塑剂与固含量等因素对流延膜性能的影响,提出了一种优化的固含量为42%的配方体系,其流延膜相对密度达79.3%。经硅粉氮化后烧结得到的Si_(3)N_(4)陶瓷相对密度≥95%,抗弯强度达(852.7±48.8)MPa,热导率达75.5 W/(m·K)。采用丝网印刷工艺印制钨金属化浆料,经热压叠层与共烧结,得到金属层与Si_(3)N_(4)基板均平直完整、无翘曲、无缺陷的Si_(3)N_(4)金属化陶瓷,经测量发现其结合强度为27.84 MPa,金属层方阻为104 mΩ/sq。研究结果表明,采用流延成型和丝网印刷工艺,经烧结工艺可以制备Si_(3)N_(4)高温多层共烧基板(HTCC)。

MAX相陶瓷增强金属基复合材料:制备、性能与仿生设计

由于原子间存在共价键、金属键与离子键的混合键合状态,MAX相陶瓷兼具金属和陶瓷材料的性能特点,并且常与金属之间表现出良好的润湿性,有助于形成强界面结合,独特的层状原子结构使MAX相陶瓷表现出良好的断裂韧性、阻尼与自润滑性能。因此,作为金属基复合材料的增强相,MAX相陶瓷具有显著优势,本文着重介绍相关研究进展。目前,MAX相陶瓷增强金属基复合材料主要通过搅拌铸造、粉末冶金和熔体浸渗等途径制备,得到的复合材料表现出优于金属基体的强度、硬度与模量,同时还具备良好的耐磨、导电、抗电弧侵蚀等性能。此外,借助真空抽滤、冰模板等工艺可实现超细片状MAX相陶瓷粉体的择优定向排列,然后利用金属熔体浸渗多孔陶瓷骨架,可获得具有类贝壳结构的MAX相陶瓷增强金属基仿生复合材料,进一步提升材料的强韧性能。MAX相陶瓷增强金属基复合材料在承载、电接触等应用领域具有显著优势和广阔前景。