The j–pH diagram of interfacial reactions involving H+ and OH-

For aqueous interfacial reactions involving H+and OH-, the interfacial pH varies dynamically during the reaction process, which is a key factor determining the reaction performance. Herein, the kinetic relevance between the interfacial pH and reaction rate is deciphered owing to the success in establishing the transport equations of H+/OH- in unbuffered solutions, and is charted as a current(j)–pH diagram in the form of an electrochemical response. The as-described j–pH interplay is experimentally verified by the oxygen reduction and hydrogen evolution reactions. This diagram serves to form a panoramic graphic view of pH function working on the interfacial reactions in conjunction with the Pourbaix’s potential–pH diagram, and particularly enables a kinetic understanding of the transport effect of H+and OH-on the reaction rate and valuable instruction toward associated pH control and buffering manipulation.

Wetting Behavior and Interfacial Reactions in (Sn-9Zn)-2Cu/Ni Joints during Soldering and Isothermal Aging

The wetting property of （Sn-9Zn）-2Cu （wt pct） on Ni substrate and the evolution of interracial microstructure in （Sn-9Zn）-2Cu/Ni joints during soldering as well as isothermal aging were studied. The wetting ability of eutectic Sn-gZn solder on Ni substrate was markedly improved by adding 2 wt pct Cu into this solder alloy. Plate-like Cu5Zn8 intermetallic compounds （IMCs） were detected in （Sn-9Zn）-2Cu solder matrix. A continuous NisZn21 IMC layer was formed at （Sn-9Zn）-2Cu/Ni interface after soldering. This IMC layer kept its type and integrality even after aging at 170℃ for up to 1000 h. At the early aging stage （before 500 h）, the IMC layer grew fast and its thickness followed a linear relationship with the square root of aging time. Thereafter, however, the thickness increased very slowly with longer aging time. When the joints were aged for 1000 h, a new IMC phase, （Cu,Ni）5Zn8, was found in the matrix near the interface. The formation of （Cu,Ni）5Zns phase can be attributed to the diffusion of Ni atoms into the solder matrix from the substrate.

Characteristics of interfacial reactions between Ti-6Al-4V alloy and ZrO2 ceramic mold

The interfacial reaction between Ti-6Al-4V alloy and ZrO2 ceramic mold with zirconia sol binder was investigated by keeping the 12 g alloy melt in a vacuum induction furnace for 15 s.The microstructures,element distribution and phase constitution of the interface were identified by optical microscopy(OM),scanning electron microscopy(SEM)equipped with energy dispersive spectroscopy(EDS)and X-ray diffraction(XRD).The results show that the whole interface reaction layer can be divided into three regions:metal penetration layer,transition layer,and hardened layer according to the structure morphology,which has the characteristics of severe metal penetration,finer lamellar,and coarse oxygen-richαphase,respectively.The erosion of the alloy melt on the ceramic mold promotes the decomposition of zirconia,which leads to the increase of local Zr concentration,greatly increasing the activity coefficient of Ti,aggravating the occurrence of interfacial reaction.Thus,the interfacial reaction shows the characteristics of chain reaction.When the oxygen released by the dissolution of zirconia exceeds the local solid solubility,it precipitates in the form of bubbles,resulting in blowholes at the interface.The result also indicates that the zirconia mold with zirconia sol binder is not suitable for pouring heavy titanium alloy castings.

Mechanisms of interfacial reactions between 316L stainless steel and MnO-SiO_(2) oxide during isothermal heating

Diffusion couple experiments were performed to study the thermodynamic and kinetic mechanisms of interfacial reactions between the 316L stainless steel and the composite MnO-SiO_(2) oxide during isothermal heating at 1473 K(1200℃)for 1,3,5,and 10 h and at 1173,1273,1373,1473,and 1573 K(900,1000,1100,1200,and 1300℃)for 3 h.Compositional variations in the 316L stainless steel and the composite MnO-SiO_(2) oxide in the vicinity of the steel-oxide interface in each diffusion couple specimen were determined.Before and after isothermal heating,thermodynamic equilibria between the oxide and steel at the interface were estimated in accordance with the calculation of the Gibbs free energy change in the interfacial steel-oxide reactions.The diffusion coefficients of Mn,Cr,and Si in 316L stainless steel under different experimental conditions were quantitatively acquired.The results showed that solid-state interfacial reactions occurred between the Cr in the 316L stainless steel and composite MnO-SiO_(2) oxide during isothermal heating,which resulted in the depletion of Cr and accumulation of Si and Mn in the steel in the vicinity of the steel-oxide interface.The widths of the Crdepleted zone,Mn-accumulated zone and Si-accumulated zone all showed increasing trends with increasing isothermal heating temperature and time.The average values of the diffusion coefficients of Mn,Cr,and Si in the steel at 1473 K(1200℃)were 1.21×10^(^(-14))±2.96×10^(-15),1.69×10^(-14)±2.54×10^(-15),and 1.00×10^(-14)±1.96×10^(-15) m^(2)s^(-1),respectively,and they continued to increase with increasing isothermal heating temperature.

Effect of Linear Electromagnetic Stirring on Behavior of Liquid Metal and Rate of Slag-Metal Interfacial Reactions

The internal flow,free surface shape,and level fluctuation of liquid metal exposed to linear electromagnetic stirring were measured and analyzed against the background of an actual metallurgical equipment with linear electromagnetic stirring system.The desulphurization process,with or without imposition of linear electromagnetic stirring,was also studied experimentally.The changes in sulfur content of hot metal with respect to time were obtained,and the volumetric mass transfer coefficients corresponding to different stirring currents were determined.The results showed that linear electromagnetic stirring can effectively promote internal flow,effectively increase the level fluctuation,and significantly improve the kinetic condition of liquid metal.The internal flow and level fluctuation of liquid metal increase in line with the increase in electromagnetic stirring intensity.The desulphurization experiments show that linear electromagnetic stirring can significantly promote the desulphurization process of hot metal,and that the technology has wide application potential in promoting various slag-metal reactions.

Interfacial design of silicon/carbon anodes for rechargeable batteries:A review

Silicon(Si)has been studied as a promising alloying type anode for lithium-ion batteries due to its high specific capacity,low operating potential and abundant resources.Nevertheless,huge volume expansion during alloying/dealloying processes and low electronic conductivity of Si anodes restrict their electrochemical performance.Thus,carbon(C)materials with special physical and chemical properties are applied in Si anodes to effectively solve these problems.This review focuses on current status in the exploration of Si/C anodes,including the lithiation mechanism and solid electrolyte interface formation,various carbon sources in Si/C anodes,such as traditional carbon sources(graphite,pitch,biomass),and novel carbon sources(MXene,graphene,MOFs-derived carbon,graphdiyne,etc.),as well as interfacial bonding modes of Si and C in the Si/C anodes.Finally,we summarize and prospect the selection of carbonaceous materials,structural design and interface control of Si/C anodes,and application of Si/C anodes in all-solid-state lithium-ion batteries and sodium-ion batteries et al.This review will help researchers in the design of novel Si/C anodes for rechargeable batteries.

Anode Interfacial Issues in Solid-State Li Batteries:Mechanistic Understanding and Mitigating Strategies

All-solid-state Li metal batteries(ASSLBs)using inorganic solid electrolyte(SE)are considered promising alternatives to conventional Li-ion batteries,offering improved safety and boosted energy density.While significant progress has been made on improving the ionic conductivity of SEs,the degradation and instability of Li metal/inorganic SE interfaces have become the critical challenges that limit the coulombic efficiency,power performance,and cycling stability of ASSLBs.Understanding the mechanisms of complex/dynamic interfacial phenomena is of great importance in addressing these issues.Herein,recent studies on identifying,understanding,and solving interfacial issues on anode side in ASSLBs are comprehensively reviewed.Typical issues at Li metal/SE interface include Li dendrite growth/propagation,SE cracking,physical contact loss,and electrochemical reactions,which lead to high interfacial resistance and cell failure.The causes of these issues relating to the chemical,physical,and mechanical properties of Li metal and SEs are systematically discussed.Furthermore,effective mitigating strategies are summarized and their effects on suppressing interfacial reactions,improving interfacial Li-ion transport,maintaining interfacial contact,and stabilizing Li plating/stripping are highlighted.The in-depth mechanistic understanding of interfacial issues and complete investigations on current solutions provide foundations and guidance for future research and development to realize practical application of high-performance ASSLB.

Wettability and Interfacial Reactions Between Metallic Glass Melts and Cu/Mo Used as Roller Materials for Twin-Roll Casting

Twin-roll casting has been recently revealed to be an effi cient technique to produce rejuvenated metallic glass(MG)strips.Due to the high melting point and high hardness,pure Mo is considered as a good roller material as pure Cu.However,the wettability and interfacial reactions between MG melts and Cu or Mo remain largely unknown.In this work,a series of sessile droplet wetting experiments are designed to investigate the wettability and reactions between Zr_(41.2)Ti_(13.8)Cu_(12.5)Ni_(10)Be_(22.5)(Vit.1)or(Zr 0.401 Ti_(0.133)Cu_(0.118)Ni_(0.101)Be_(0.247))_(99)Nb_(1)(Nb1)MG melts and Cu/Mo substrates at temperatures of 1073,1123 and 1173 K.It is found that the wettability and interfacial reactions of the Vit.1 and Nb1 MG melts on the Cu substrates are very similar.The equilibrium contact angles are~30°at 1073 K and~25°-27°at 1123 K.The MG melts completely spread out on the Cu substrates at 1173 K.Cu substrates are slightly dissolved in the MG melts event at 1073 K,and a transitional reaction layer exists between the droplet and the Cu substrate.In comparison,the Vit.1 MG melt exhibits a much improved wettability on the Mo substrate.The equilibrium contact angle of the Vit.1/Mo is only 6°at 1073 K and 5°at 1123 K.No signifi cant diff usion of Mo into the droplet occurs even at 1173 K with a holding time of~30 min.The interfaces of the Vit.1/Mo samples are sharp,and no interfacial reaction layers form.These fi ndings indicate that pure Mo can be a good roller material for twin-roll casting at high temperatures,and the Mo-made rollers are expected of capability to produce MG strips with good quality.

Interfacial reaction behavior and mechanical properties of 5A06 Al alloy soldered with Sn-1Ti-xGa solders at a low temperature

Active soldering of 5A06 Al alloy was performed at 300 ℃ by using Sn-1Ti and Sn-1Ti-0.3Ga active solders, respectively. Theeffects of soldering time on the microstructure and mechanical properties of the joints were investigated. The results showed that the Sn-1Tisolder broke the oxide film on the surface of the Al substrate and induced intergranular diffusion in the Al substrate. When Ga was added tothe solder, severe dissolution pits appeared in the Al substrate due to the action of Sn-1Ti-0.3Ga solder, and many Al particles were flakedfrom the matrix into the solder seam. Under thermal stress and the Ti adsorption effect, the oxide film cracked. With increasing solderingtime, the shear strength of 5A06 Al alloy joints soldered with Sn-1Ti and Sn-1Ti-0.3Ga active solders increased. When soldered for 90 min,the joint soldered with Sn-1Ti-0.3Ga solder had a higher shear strength of 22.12 MPa when compared to Sn-1Ti solder.

C/Ti/Cu interfacial reaction in SiCf/Cu composites

Continuous SiC fiber reinforced copper matrix （SiC~/Cu） composites were prepared by fiber coating method, and Ti6A14V interlayer was introduced as an interfacial modification coating to improve the interfacial bonding strength. The interfacial reaction characteristics were investigated by transmission electron microscopy （TEM）. The results show that nearly all the titanium atoms reacted with the carbon coating of SiC fibers to form two layers of TiC. Also, a thin copper layer that is sandwiched between these two layers was detected. No Ti-Cu interfacial reaction product was observed. The formation process of the interfacial reaction along with its mechanism was discussed.

Electrochemical and spectroscopic study of interfacial interactions between chalcopyrite and typical flotation process reagents

Comparative voltammetry and differential double-layer capacitance studies were performed to evaluate interfacial interactions between cnalcopyrite（CuFeS2） and n-isopropyl xanthate（X） in the presence of ammonium bisulfite/39wt%SO2 and caustic starch at different pH values.Raman spectroscopy,Fourier transform infrared（FTIR） spectroscopy,contact angle measurements,and microflotation tests were used to establish the type and extent of xanthate adsorption as well as the species involved under different mineral surface conditions in this study.The results demonstrate that the species that favor a greater hydrophobicity of chalcopyrite are primarily CuX and S^0,whereas oxides and hydroxides of Cu and Fe as well as an excess of starch decrease the hydrophobicity.A conditioning of the mineral surface with ammonium bisulfite/39wt%SO2 at pH 6 promotes the activation of surface and enhances the xanthate adsorption.However,this effect is diminished at pH ≥ 8,when an excess of starch is added during the preconditioning step.

Kinetics and Mechanism of Interfacial Reaction in a SiC_f/Ti Composite

In order to evaluate the interfacial reaction, a SiCf/Ti (TA1) composite was fabricated by a vacuum hot pressing method and then heat-treated in vacuum at 800℃ for up to 100 h. The elemental distributions of C, Si and Ti at the interfacial reaction zone were investigated. It was found that the reaction zone occurs during the fabrication process and continuously grows at high temperature because the Si and C atoms diffuse from SiC fibers to the matrix and Ti atoms diffuse in the opposite direction. The growth of the reaction zone is diffusion controlled and the mechanism of the reaction can be described by a reactive diffusion model of solid-state growth of an AmBn layer between two elementary substances A and B.

Effect of infiltrating time on interfacial reaction and properties of tungsten particles reinforced Zr-based bulk metallic glass composites

The tungsten particles reinforced Zr41.2Ti13.8Cu12.5Ni10Be22.5 (Vit 1 alloy) bulk metallic glass composites (BMGCs) were prepared by the melt infiltrating casting method with the infiltrating time of 1, 5 and 10 min, respectively. The changes of interfacial reaction and compression properties of the bulk metallic glass composites with different infiltrating times were studied. Results show that with the increase of infiltrating time, tiny nanocrystals are generated at the interfacial boundary of tungsten particles and the amorphous matrix, and the size of tiny crystals increases with the infiltrating time. When the infiltrating time is 10 min, polygonal crystals with a larger size are also generated within the amorphous matrix. The compressive strength of the composites also increases with the infiltrating time. When the infiltrating time is 10 min, the compressive strength of the composite reaches 2,030 MPa and the compression strain is 44%. The fracture morphology of the composite materials is in a vein-like pattern and the melting phenomenon is found on the fracture surface. In addition, the density of the shear bands during the compressive tests of the composite materials increases with the infiltrating time.

Preparation and Interfacial Stability of SiC_f/Ti-6Al-4V Composites Fabricated Using Powder Coated Fiber Method

SiCf/Ti-6Al-4V composites were fabricated by the powder-coated fiber method. The precursor fiber was prepared under the optimized parameter, and the composites were made using the vacuum hot pressure method. The influence of heat exposure time on products of thelinterfacial reaction was investigated using scanning electron microscope （SEM） and analytical transmission electron microscope （TEM） with energy dispersive spectrometer （EDS）. The main products are TiC and Ti5Si3 after vacuum exposing the samples at 700℃ for 50 h. The growth dynamics of interracial reaction products was analyzed quantitatively, which fitted the parabola rule. The activity energy of the reaction was 252 kJ·mol^-1.

Mechanism of the Interfacial Reaction of AI_2O_3/Medium Mn Steel Containing Nb

The mechanism of the interfacial reaction of Al_2O_3/medium Mn steel containing Nb was studied by means of the observation on the interfacial reaction phenomenon of Al_2O_3/medium Mn steel,and the analyses on the interracial phases.The results show that when T≥1550℃,the interfacial reac- tion of Al_2O_3/medium Mn steel containing Nb happened.In the medium Mn steel matrix,Nb exists in the form of NbC.NbC are the nucleating base of CO gas bubbles.

Interfacial phenomena in electric field-assisted anodic bonding of Kovar/Al film-glass

Anodic bonding of glass to Kovar alloy coated with Al film (Glass Al film/Kovar) was performed in the temperature range of 513 ～ 713?K under the static electric voltage of 500?V in order to investigate the interfacial phenomena of Al glass joint. The results reveal that Na and K ions within the glass are displaced by the applied field from the anode side surface of the glass to form depletion layers of them. The K ion depletion layer is narrow and followed by a K pile up layer, and both the two layers are formed within the Na depletion layer. The width of the Na and K depletion layers is increased with increasing bonding temperature and time. The activation energies for the growth of both depletion layers were close to that for Na diffusion in the glass. TEM observations reveal that Al film coated at the surface of Kovar alloy is oxidized to amorphous Al 2O 3 containing a few of Fe, Ni and Co by oxygen ions from the glass drifted by high electric field during bonding. The amount of Fe ions diffusing into the glass adjacent to the anode is significantly low due to the presence of Al film between Kovar alloy and the glass. As a result, the amorphous reaction layer of Fe Si O in the glass near the interface is avoided which is formed in Kovar glass joints.

Wettability of CuNi-Ti Alloys on Si_3N_4 and Interfacial Reaction Products

Based on the alloy Cu55Ni45 (at pct), holding the proportion of Cu to Ni in constant and in the temperature range of 1233~1573 K, the wetting angles of CuNi-0~56 at pct Ti alloys on Si3N4 have been measured by the sessile drop method. With the increase of Ti content, the wetting angles decreased. The equilibrium wetting angle was 5° when Ti content ≥32 at pct.In the case of same Ti content, the activity of Ti in CuNiTi alloy was weaker than that in CuTi alloy The cross-section of the CuNiTi-Si3N4 interface and the elements distribution were examined by scanning electron microscope with X-ray wave-dispersion spectrometer, and the reaction products formed at the interface were determined by X-ray diffiaction analysis method.

Interfacial reaction in squeeze cast SiC_w/AZ91 composites with different binders

The whisker/matrix interfaces in squeeze cast SiC w/AZ91 composites with different binders (silica binder, acid aluminum phosphate binder and without binder), were studied by transmission electron microscopy (TEM) and high resolution electron microscopy (HREM). The SiC w/AZ91 interface is very clean in the composites with no binders. For the composites with acid aluminum phosphate binders or silica binders, there exists fine discrete interfacial reaction products MgO at the interface, and a definite orientation relationship between MgO and SiC w. The interfacial reaction products MgO is unevenly distributed at different parts of the composite ingot with silica binder, and mainly distributed to the interface at the side part of the composite cylinder. While in the SiC w/AZ91 composite with acid aluminum phosphate binder, MgO particles are distributed evenly at the interface in almost all the parts of the composite ingot. [

FINE STRUCTURES OF BOTH INTERFACES AND INTERFACIAL REACTION PRODUCTS

The characteristic of interface depending on the atomic structure exerts an inportant,and sometime controlling,influence on performance of the interacial materials. The present paper reviews the main studies on fine structure of both the materials inter- faces and interfacial reaction products in semiconductor uperlattice,metal multilayer ceram- ics and composite materials by mean of selected area electron doffraction patterns and high resolution electron microscopy. The following features of interfaces are reviewed:the orientation relationships;the char- acteristic of steps,facets and ronghness of interfaces;atomic bonding across the interface;the degree of coherency,the structure of misfit dislocations and elastic relaxations at the inter- faces:the presence of defects at the onterfaces:the structure of the interfacial reaction prod- ucts as well as the reaction kinetics and reaetion mechanism.

Effects of Pouring Temperature on Interfacial Reaction between Ti-47-5Al-2-5V-1Cr Alloy and Mold during Centrifugal Casting

Pouring temperature and time are the most important influencing factors on interfacial reaction during the centrifugal casting. When cast at high temperatures, the crucible becomes brittle and prone to cracking, and shows a low stability. In this paper, we studied the centrifugal casting of Ti-47.5-Al-2.5V-1Cr alloy, and explored the effects of pouring temperature on the interfacial reaction. Castings at 1 600, 1 650, and 1 700 ℃ were obtained by controlling the other parameters constant in the experiments. The microstructure, elemental distribution, thickness of the reaction layer and phase composition of the castings at the interface were studied. The results show that the thickness at the interfacial reaction layer is increased by raising the pouring temperature. The elements in the mold and the matrix were double-diffused and reacted at the interface during the casting process, and formed solid solutions with the precipitation of many new phases such as AlOand TiO. The roughness of interface structure and layer thickness of reaction increase with the rise of temperature, and the interfacial reaction is more intense. There is a minimum layer thickness of the reaction layer that is 80 μm when the temperature is 1 600 ℃.