An Efficient Boron Source Activation Strategy for the Low‑Temperature Synthesis of Boron Nitride Nanotubes

Lowering the synthesis temperature of boron nitride nanotubes(BNNTs)is crucial for their development.The primary reason for adopting a high temperature is to enable the effective activation of highmelting-point solid boron.In this study,we developed a novel approach for efficiently activating boron by introducing alkali metal compounds into the conventional MgO–B system.This approach can be adopted to form various low-melting-point AM–Mg–B–O growth systems.These growth systems have improved catalytic capability and reactivity even under low-temperature conditions,facilitating the synthesis of BNNTs at temperatures as low as 850℃.In addition,molecular dynamics simulations based on density functional theory theoretically demonstrate that the systems maintain a liquid state at low temperatures and interact with N atoms to form BN chains.These findings offer novel insights into the design of boron activation and are expected to facilitate research on the low-temperature synthesis of BNNTs.

Rare Earth-Boronizing and Its Applications

The thickness, brittleness, boron content and morphology of RE boronized layer were investigated. The results show that the service life of the boronized layer in molten zinc can be increased by adding RE element. The thermocouple and sink roll sleeve made of this material can be used for more than half a year.

Boronizing Process of A Solid Boronizing Supply Agent with Rare Earths

The boronizing supply agent of a low-priced solid with RE, the experimental of the boronizing process and the amount of adding RE were studied. The function of RE was discussed. The results show that the symmetrical and dense boronized layer can be obtained on the surface of steel by using the solid boronizing supply agent with RE element for boronizing, RE can deduce the temperature of boronizing and increase the rate of boronizing and the hardness of boronized layer, and it can also improve the distribution of hardness of boronized layer. The best condition of the solid boronizing supply agent is at 860 ℃ for 4～6 h, and the addition amount of RE is 6%(mass fraction).

Preparation of wettable TiB2-TiB/Ti cathode by electrolytic boronizing for aluminum electrolytic

According to the problems of short life and low strength of TiB2 coating cathode for current technology in aluminium electrolysis industry,this work synthesized TiB2-TiB/Ti gradient composite with TiB2 coating and TiB whiskers in metallic Ti matrix by a electrolytic boronizing method based on similar density and thermal expansivity of the three materials.The phase composition and morphology of the cross-section were determined by X-ray diffraction(XRD),scanning electronic microscope(SEM)and X-ray energy dispersive spectrum(EDS).The results show that uniform TiB2 layer with a thickness of 8-10μm is continuously coated on the surface while the TiB whisker connected with TiB2 layer was embedded dispersedly into the matrix.The TiB crystal whisker has a maximum length of about 220μm.The growth rate of TiB2 and TiB is enhanced by the strong reduction of B4C.The novel gradient design of the composite helps to extend life and improve strength of the TiB2 cathode in aluminium electrolysis.

Effect of Rare Earths on Structure and Properties of Carbonitriding Boronizing Combined Treatment

The microstructure, thickness, microhardness and wear resistance of single-boronizing, carbonitriding+boronizing and carbonitriding+RE-boronizing layers of 16Mn steel were investigated respectively. Effect of rare earths on microstructure and properties of the penetrated layer were studied and the mechanism of effects of rare earths was discussed. The result showed that the structure, microhardness, brittleness and wear resistance of the penetrated layer after carbonitriding+ RE-boronizing were better than that of conventional boronizing and carbonitriding, especially the wear resistance of boronized layer was increased remarkably. The RE-boronizing layer of the steel is single phase Fe2B, and RE elements enhanced Fe2B (002) direction texture. The distribution of rare earth element (La) in the layer was non-uniform. RE content is higher between borides than that of the interior of borides. An optimum value of the addition of RE element in the agent was 8%. The average service life of the 16Mn steel brick mould treated by carbonitriding+RE-boronizing was 1.5 times as long as the service life of the mould treated by carbonitriding-boronizing.

Preliminary discussion on the ignition mechanism of exploding foil initiators igniting boron potassium nitrate

Exploding foil initiator(EFI)is a kind of advanced device for initiating explosives,but its function is unstable when it comes to directly igniting pyrotechnics.To solve the problem,this research aims to reveal the ignition mechanism of EFIs directly igniting pyrotechnics.An oscilloscope,a photon Doppler velocimetry,and a plasma spectrum measurement system were employed to obtain information of electric characteristics,impact pressure,and plasma temperature.The results of the electric characteristics and the impact pressure were inconsistent with ignition results.The only thing that the ignition success tests had in common was that their plasma all had a relatively long period of high-temperature duration(HTD).It eventually concludes that the ignition mechanism in this research is the microconvection heat transfer rather than the shock initiation,which differs from that of exploding foil initiators detonating explosives.Furthermore,the methods for evaluating the ignition success of semiconductor bridge initiators are not entirely applicable to the tests mentioned in this paper.The HTD is the critical parameter for judging the ignition success,and it is influenced by two factors:the late time discharge and the energy of the electric explosion.The longer time of the late time discharge and the more energy of the electric explosion,the easier it is to expand the HTD,which improves the probability of the ignition success.

Unraveling the role of dual Ti/Mg metals on the ignition and combustion behavior of HTPB-boron-based fuel

Metal additives play an essential role in explosive and propellant formulations. Boron(B) is widely used in propellant applications owing to its high energetic content. The addition of B to explosives and propellants increases their energy density, making them more efficient and powerful. Nevertheless, B forms oxide layers on its surface during combustion, slowing down the combustion rate and reducing rocket motor efficiency. To overcome this issue, other metal additives such as aluminum(Al), magnesium(Mg),and titanium(Ti) are revealed to be effective in boosting the combustion rate of propellants. These additives may improve the combustion rate and therefore enhance the rocket motor’s performance. The present study focused on preparing and investigating the ignition and combustion behavior of pure hydroxyl-terminated polybutadiene(HTPB)-B fuel supplemented with nano-titanium and nanomagnesium. The burn rates of HTPB-B fuel samples were evaluated on the opposed flow burner(OFB)under a gaseous oxygen oxidizer, for which the mass flux ranges from 22 kg/(m^(2)·s) to 86 kg/(m^(2)·s). The addition of Ti and Mg exhibited higher regression rates, which were attributed to the improved oxidation reaction of B due to the synergetic metal combustion effect. The possible combustion/oxidation reaction mechanism of B-Mg and B-Ti by heating the fuel samples at 900℃ and 1100℃ was also examined in a Nabertherm burnout furnace under an oxygen atmosphere. The post-combustion products were collected and further subjected to X-ray diffraction(XRD) and field emission scanning electron microscopy(FE-SEM) analyses to inspect the combustion behavior of B-Ti and B-Mg. It has been observed that the B oxide layer at the interface between B-Ti(B-Mg) is removed at lower temperatures, hence facilitating oxygen transfer from the surroundings to the core B. Additionally, Ti and Mg decreased the ignition delay time of B, which improved its combustion performance.

Flexible and Robust Functionalized Boron Nitride/Poly(p‑Phenylene Benzobisoxazole)Nanocomposite Paper with High Thermal Conductivity and Outstanding Electrical Insulation

With the rapid development of 5G information technology,thermal conductivity/dissipation problems of highly integrated electronic devices and electrical equipment are becoming prominent.In this work,“high-temperature solid-phase&diazonium salt decomposition”method is carried out to prepare benzidine-functionalized boron nitride(m-BN).Subsequently,m-BN/poly(pphenylene benzobisoxazole)nanofiber(PNF)nanocomposite paper with nacremimetic layered structures is prepared via sol–gel film transformation approach.The obtained m-BN/PNF nanocomposite paper with 50 wt%m-BN presents excellent thermal conductivity,incredible electrical insulation,outstanding mechanical properties and thermal stability,due to the construction of extensive hydrogen bonds andπ–πinteractions between m-BN and PNF,and stable nacre-mimetic layered structures.Itsλ∥andλ_(⊥)are 9.68 and 0.84 W m^(-1)K^(-1),and the volume resistivity and breakdown strength are as high as 2.3×10^(15)Ωcm and 324.2 kV mm^(-1),respectively.Besides,it also presents extremely high tensile strength of 193.6 MPa and thermal decomposition temperature of 640°C,showing a broad application prospect in high-end thermal management fields such as electronic devices and electrical equipment.

Fabrication and characterization of multi-scale coated boron powders with improved combustion performance:A brief review

Boron has high mass and volume calorific values,but it is difficult to ignite and has low combustion efficiency.This literature review summarizes the strategies that are used to solve the above-mentioned problems,which include coatings of boron by using fluoride compounds,energetic composites,metal fuels,and metal oxides.Coating techniques include recrystallization,dual-solvent,phase transfer,electrospinning,etc.As one of the effective coating agents,the fluorine compounds can react with the oxide shell of boron powder.In comparison,the energetic composites can effectively improve the flame temperature of boron powder and enhance the evaporation efficiency of oxide film as a condensed product.Metals and metal oxides would react with boron powder to form metal borides with a lower ignition point,which could reduce its ignition temperature.

Effect of Surface Nanocrystallization Induced by Fast Multiple Rotation Rolling on Cr-Rare Earth-Boronizing for Steel 45 under Low-Temperature

In this paper, fast multiple rotation rolling （FMRR） is applied to fabricate a nanostructured layer on the surface of steel 45. The FMRR samples are then Cr-Rare earth-boronized under low-temperature. The boride layer is characterized by using Scanning electron microscopy （SEM） and X-ray diffraction （XRD）. Experimental results indicate that the thickness of the boride layer is greatly increased by surface nanocrystallization. The boride layer with relatively continuous structure instead of the zigzag teeth structure is obtained, and the penetrating rate is enhanced by 2. 5-3.7 times when the FMRR samples are Cr-Rare earth- boronized at the temperature of 570 %, 600℃ and 650℃ for 6 h. The boride layer fabricated on the FMRR sample consists of single phase Fe2B. Severe plastic deformation with the grain size of approximately 100 nm in the top surface layer of steel 45 is observed, and the thickness of the plastic deformation layer is about 30 6xm. The microstructure in the top surface layer is characterized by Transmission electron microscopy （TEM）. Grain boundaries are largely increased with high stacking fault energy after FMRR, leading to a significant enhancement of RE boron-chromizing speed.

Recension of boron nitride phase diagram based on high-pressure and high-temperature experiments

Cubic boron nitride and hexagonal boron nitride are the two predominant crystalline structures of boron nitride.They can interconvert under varying pressure and temperature conditions.However,this transformation requires overcoming significant potential barriers in dynamics,which poses great difficulty in determining the c-BN/h-BN phase boundary.This study used high-pressure in situ differential thermal measurements to ascertain the temperature of h-BN/c-BN conversion within the commonly used pressure range(3-6 GPa)for the industrial synthesis of c-BN to constrain the P-T phase boundary of h-BN/c-BN in the pressure-temperature range as much as possible.Based on the analysis of the experimental data,it is determined that the relationship between pressure and temperature conforms to the following equation:P=a+1/bT.Here,P denotes the pressure(GPa)and T is the temperature(K).The coefficients are a=-3.8±0.8 GPa and b=229.8±17.1 GPa/K.These findings call into question existing high-pressure and high-temperature phase diagrams of boron nitride,which seem to overstate the phase boundary temperature between c-BN and h-BN.The BN phase diagram obtained from this study can provide critical temperature and pressure condition guidance for the industrial synthesis of c-BN,thus optimizing synthesis efficiency and product performance.

Equation of state for boron nitride along the principal Hugoniot to 16 Mbar

The thermodynamic properties of boron nitride under extreme pressures and temperatures are of great interest and importance for materials science and inertial confinement fusion physics,but they are poorly understood owing to the challenges of performing experiments and realizing ab initio calculations.Here,we report the first shock Hugoniot data on hexagonal boron nitride at pressures of 5–16 Mbar,using hohlraum-driven shock waves at the SGIII-p laser facility in China.Our density functional theory molecular dynamics calculations closely match experimental data,validating the equations of state for modeling the shock response of boron nitride and filling a crucial gap in the knowledge of boron nitride properties in the region of multi-Mbar pressures and eV temperatures.The results presented here provide fundamental insights into boron nitride under the extreme conditions relevant to inertial confinement fusion,hydrogen–boron fusion,and high-energy-density physics.

Comparative study of boron and neon injections on divertor heat fluxes using SOLPS-ITER simulations

Based on the EAST equilibrium,the effects of boron(B)and neon(Ne)injected at different locations on the target heat load,and the distributions of B and Ne particles were investigated by transport code SOLPS-ITER.It was found that the B injection was more sensitive to the injection location for heat flux control than impurity Ne.The high electron and ion densities near the inner target in the discharge with impurity B injected from over X-point(R1)led to plasma detachment only at the inner target,and the localized B ions in the cases with injection from outer target location(R2)and upstream location(R3)led to far-SOL detachment at the outer target,but not at the inner target.In contrast,for Ne,the spatial distributions of Ne ions and electrons were found to be similar in all the cases at the three injection locations,and the detached plasma was achieved at the inner target and the electron temperature was reduced at the outer target.For locations R2 and R3,impurity B showed a more pronounced effect on the heat flux at the far-SOL of the outer target.Further analysis indicated that Ne atoms came mainly from the recycling sources,whereas B atoms came mainly from injection,and that their distinct atomic distributions resulted from the difference in the ionization threshold and ionization mean free path.In addition,the radiation proportion of B in the divertor region was larger than that of Ne when the total radiation power was similar,which suggests that B has less influence on the core region.

Isotherm,kinetic and thermodynamic investigations of boron phosphide to remove methylene blue from aqueous solution

In this work,the boron phosphide(BP)was synthesized and used for the adsorptive removal of methylene blue(MB)dye from aqueous solutions.To determine the optimum adsorption conditions,studies were performed by varying parameters of temperature(298–328 K),pH(2–12),contact time(0–120 min),adsorbent dose(0.01–0.20 g/50 mL),and dye concentration(10–50 mg/L).Different isotherm and kinetic models were applied to the adsorption data.The linear correlations coefficient showed that the Langmuir isotherm best fits(R^(2)=0.9996).The maximum adsorption capacity of BP was obtained as 555.56 mg/g at 55℃and the removal rate reached up to 84.11%.Additionally,the pseudo-second-order kinetic model described the adsorption process best(R^(2)=0.9998).The thermodynamic studies represented that the adsorption occurred spontaneously(ΔG_(A)^(Θ)=−24.90 kJ/mol)and endothermically(ΔH_(A)^(Θ)=16.67 kJ/mol).The results showed that BP is an efficient adsorbent for removing cationic dyes from aqueous solutions.

The source of lithium in Lakkor Co Salt Lake on Qinghai-Tibet Plateau,China:evidence from hydrochemical characteristics and boron isotope

The availability of lithium resources is of great significance for the development of modern technologies,as well as for civil and military industries.The Qinghai-Tibet Plateau is a region known for its abundance of lithium-rich salt lakes.However,the specific origin of lithium in these lakes is still unknown,which hinders the advancement of the lithium resource business in this region.To research this issue,this study involved the collection of 20 samples from Lakkor Co Salt Lake on Qinghai-Tibet Plateau,encompassing samples of surface brine,cold springs,fresh lakes,and recharge rivers.The composition of anions and cations in these samples was determined.Furthermore,the analysis extensivelyutilizedthePiperthree-linediagram,Gibbs model,and ion proportion coefficient.The findings of this study indicate that as the moves from the recharge water system to salt lake,there is a transition in water type from strong carbonate to moderate carbonate and weak carbonate,as well as Na sulfate.This research based on a similar source of both lithium and boron,utilized ion correlation analysis and boron isotope study in the Lakkor Co area,and analyzed the source and transporting process of lithium.The main origin of lithium in Lakkor Co is the dissolution of lithiumrich rocks,recharge water systems,and deep hydrothermal fluids.These findings are highly significant in enhancing the foundational data of lithium-rich brine resources in the Qinghai-Tibet Plateau and are beneficial for assessing the future development of such deposits.

Plasma boronizing of Ti6AlV4 using solid precursors by double glow plasma alloying technique

Solid state B-offerings (FeB compound) were used for plasma-assisted boronizing on Ti6Al4V alloy by double glow discharge plasma alloying technique (DGPSA). During all experiment processing there was no harmful and toxic. The thickness and morphology, phase formation, elements concentrations and wear properties of boride layers were examined by means of optical microscopy, Vickers microhardness, X-ray diffraction, glow discharge optical emission spectroscopy and Ball-disk wear tests. The results show that friction coefficient of boride alloying samples versus corundum ball is lower than that of Ti6Al4V samples, as well as wear rate. This indicates that plasma-assisted boronizing of Ti6Al4V alloy has a high potential for industrial applications under tribological conditions.

Spark Plasma Sintering of Boron Carbide Using Ti_(3)SiC_(2) as a Sintering Additive

Boron carbide has unique properties for wide application possibilities;however,poor sinterability limits its applications.One approach to overcome this limitation is the addition of secondary phases into boron carbide.Boron carbide based composite ceramics are produced by the direct addition of secondary phases into the structure or via reactive sintering using a sintering additive.The present study investigated the effect of Ti_(3)SiC_(2) addition to boron carbide by reactive spark plasma sintering in the range of 1700-1900℃.Ti_(3)SiC_(2) phase decomposed at high temperatures and reacted with B4C to form secondary phases of TiB2 and SiC.The results demonstrated that the increase of Ti_(3)SiC_(2) addition(up to 15 vol%)effectively promoted the densification of B4C and yielded higher hardness.However,as the amount of Ti_(3)SiC_(2) increased further,the formation of microstructural inhomogeneity and agglomeration of secondary phases caused a decrease in hardness.

Stability and melting behavior of boron phosphide under high pressure

Boron phosphide(BP)has gained significant research attention due to its unique photoelectric and mechanical properties.In this work,we investigated the stability of BP under high pressure using x-ray diffraction and scanning electron microscope.The phase diagram of BP was explored in both B-rich and P-rich environments,revealing crucial insight into its behavior at 5.0 GPa.Additionally,we measured the melting curve of BP from 8.0 GPa to 15.0 GPa.Our findings indicate that the stability of BP under high pressure is improved within B-rich and P-rich environments.Furthermore,we report a remarkable observation of melting curve frustration at 10.0 GPa.This study will enhance our understanding of stability of BP under high pressure,shedding light on its potential application in semiconductor,thermal,and light-transmitting devices.

Applying Boron Fertilizer at Different Growth Stages Promotes Boron Uptake and Productivity in Rice

Boron(B)is an essential micronutrient for plant growth and yield.We investigated the optimal growth stage for B fertilizer application to improve rice production.The study was conducted using a 2×4 factorial design in a randomized complete block during the rainy season of 2022.We utilized two premium Thai rice varieties Khao Dawk Mali 105(KDML105)and Pathum Thani 1(PTT1),and four soil B fertilizer treatments:a control(no B application),B application at the tillering stage,B application at the flowering stage,and B application at both the tillering and flowering stages.The results showed that the application of B fertilizer at the flowering stage and at both the tillering and flowering stages increased grain yield of KDML105 by 25.0%and 34.0%,respectively.In contrast,the grain yield of PTT1 showed no response to B application.The increased grain yield of KDML105 was attributed to an increased number of panicles per plant and a higher filled grain rate,which was due to the elevated B concentration in all plant parts and the total B uptake,particularly when B was applied at the flowering and tillering stages.Notably,B application increased the fertilized grain rates and reduced the proportion of unfertilized grains,a phenomenon that corresponded with the increased B concentration across all plant parts.The total B uptake ranged from 5.11 to 15.85 mg/m^(2) in KDML105 and from 8.37 to 24.26 mg/m^(2) in PTT1,with the highest total B uptake observed when B was applied at both the tillering and flowering stages for both rice varieties.

Boron-containing compounds as labels,drugs,and theranostic agents for diabetes and its complications

Diabetes is a disease with a high global burden.Current strategies have failed to limit the advancement and impact of the disease.Successful early diagnosis and treatment will require the development of new agents.In this sense,boroncontaining compounds have been reported as agents with the ability to reduce glycemia and lipidemia.They have also been used for labeling and measuring carbohydrates and other molecules linked to the initial stages of diabetes and its progression.In addition,certain boron compounds bind to molecules related to diabetes development and their biological activity in the regulation of elevated glycemia.Finally,it should be noted that some boron compounds appear to exert beneficial effects on diabetes complications such as accelerating wound healing while ameliorating pain in diabetic patients.