Investigation of Microstructure and Phase Composition of Chromic Oxide, AZS/Cr and High-alumina Refractories after Exposure of Basalt and Aluminaboronsilicate Glasses Melts

The microstructure and phase composition of high-alumina,chromic oxide,and AZS/Cr refractories containing 30%and 60%(by mass)Cr_(2)O_(3) after exposure to aluminaboronsilicate glasses and basalt melts depending on the type of melts and temperature have been studied.The mechanisms of refractory corrosion by the used melts and the factors contributing to the inhibition of corrosion development have been investigated by the method of petrographic analysis.On the basis of obtained results,the use of high-alumina,chromic oxide,and AZS/Cr refractories in the sections of glass furnace linings,experiencing the intensive impact of aluminaboronsilicate glasses and basalt melts,has been confirmed and scientifically substantiated.

Multi-Level Inverter Linear Predictive Phase Composition Strategy for UPQC

The power system is facing numerous issues when the distributed gen-eration is added to the existing system.The existing power system has not been planned with flawless power quality control.These restrictions in the power trans-mission generation system are compensated by the use of devices such as the Static Synchronous Compensator(STATCOM),the Unified Power Quality Con-ditioner(UPQC)series/shunt compensators,etc.In this work,UPQC’s plan with the joint activity of photovoltaic(PV)exhibits is proposed.The proposed system is made out of series and shunt regulators and PV.A boost converter connects the DC link to the PV source,allowing it to compensate for voltage sags,swells,vol-tage interferences,harmonics,and reactive power issues.In this paper,the fea-tures of a seven-level Cascaded H-Bridge Multi-Level idea are applied to shunt and series active filter changeovers to reduce Total Harmonic Distortion and com-pensate for voltage issues.Despite its power quality capacity for common cou-pling,the proposed system can inject the grid’s dynamic power.During voltage interference,it can also provide a piece of delicate burden power.The simulation is carried out with the help of MATLAB/SIMULINK programming,and the results are compared to those of other conventional methods.

Influence of processing parameters on the phase composition of ZrN-Si_3N_4 synthesized from zircon

The optimum parameters were determined for synthesizing ZrN-Si3N4 composite powder from zircon by carbothermal reduction-nitridation （CTRN） process. The samples were prepared by mixing the carbon black of an average particle size less than 30 μm and the zircon of 40 μm with C/ZrSiO4 mass ratios of 0.2, 0.3, 0.4, and 0.5. The prepared samples were subjected to the CTRN process at temperatures of 1673, 1723, 1753, and 1773 K for 6, 9, and 12 h. The CTRN process was conducted in an atmosphere-controlled tubular furnace in a nitrogen gas flow of 1.0 L/rain. All the products were examined by X-ray powder diffraction to determine the transformation. The results showed that the proper transformation of ZrN-Si3N4 occurred at 1773 K for 12 h with a C/ZrSiO4 mass ratio of 0.4.

Highly active mixed-phase TiO_2 photocatalysts fabricated at low temperature and the correlation between phase composition and photocatalytic activity

The idea of varying volume ratio of water to ethanol in solvent was firstly employed to yield phase composition controllable mixed- phase titanium dioxide (TiO2) photocatalysts via a low temperature solvothermal route at 353 K. It was found that anatase contents increase from 0 to 100% with increase of ethanol contents in solvent. The mixed-phase TiO2 with 60% anatase content exhibited the best photocatalytic activity in photodecomposing formaldehyde (FAD) under UV light irradiation, which increases by abou...

Structure of the Intermetallic Compound Ni_3Al Synthesized under Compression of the Powder Mixture of Pure Elements Part Ⅰ: Phase Composition and Microstructure of Main Phase

It was shown by TEM and X-ray analysis that there are four types of grains of the main Ni3Al phase in the structure of the intermetallic obtained by the self-propagation high temperature method (SHS). Every type of grains has its own domain and dislocation structure. There are mono- and polydomains with and without dislocations. The grains of the main phase of monoand polydomains without dislocations and polydomains with dislocations were formed by diffusion in the solid phase. In these conditions NiAl3 phase is located on the grain boundary of the main phase. The Ni2Al3 phase is located at the triple joints of the main phase.

Morphology and Phase Compositions of Hydroxyapatite Powder Particles Plasma-sprayed into Water

Hydroxyapatite powder particles were plasma sprayed into water, their inner structures and phase compositions were studied by using scanning electron microscope(SEM) and X-ray diffractometer. The results show that the molten HA particles have a central hollow morphology and high crystallinity. The hollow morphology was caused by sublimated P2O5 and H2O, which will have an effect on surface morphology, cohesive and adhesive strength as well as dissolution and degradation of coating. The high crystallinity is attributed to lower cooling speed in water.

INFLUENCE OF PHASE COMPOSITION ON PITTING CORROSION RESISTANCE OF SPUTTERED COATING OF 1Cr18Ni9Ti STAINLESS STEEL

A series of single bcc,bcc plus fcc duplex and single fcc microcrystalline coatings of 1Cr18Ni9Ti stainless steel were prepared by using sputtering technique.The resistance against pitting corrosion was studied by measurements of pitting corrosion potentials and electrochemical noise during initiation of corrosion pits.The results show that the sputtered coatings with single bcc phase or single fcc structure are more resistant to pitting corrosion than those with bcc plus fcc duplex phase structure.

Effect of chemical composition on the element distribution,phase composition and calcification roasting process of vanadium slag

The chemical composition of vanadium slag significantly affects its element distribution and phase composition,which affect the subsequent calcification roasting process and vanadium recovery.In this work,seven kinds of vanadium slags derived from different regions in China were used as the raw materials to study the effects of different components on the vanadium slag’s elements distribution,phase composition,calcification roasting,and leaching rate of major elements using scanning electron microscope,X-ray diffraction analysis,and inductively coupled plasma-optical emission spectroscopy.The results show that the spinel phase is wrapped with silicate phase in all vanadium slag samples.The main elements in the spinel phase are Cr,V,and Ti from the interior to the exterior.The size of spinel phase in low chromium vanadium slag is larger than the other vanadium slags with higher chromium contents.The spinel phase of high-calcium and high-phosphorus vanadium slag is more dispersed.The strongest diffraction peak of vanadium spinel phase in the vanadium slag migrates to a higher diffraction angle,and(Fe_(0.6)Cr_(0.4))_(2)O_(3)is formed after calcification roasting as the chromium content increased.A large amount of Ca_(2)SiO_(4)is produced because excess Ca reacts with Si in high-calcium and high-phosphorus vanadium slag.The vanadium leaching rate reaches 88%in some vanadium slags.The chromium leaching rate is less than 5%in all vanadium slags.The silicon leaching rate of high-calcium and high-phosphorus vanadium slag is much higher than that of the other slags.The leaching rate of manganese is higher than 10%,and the leaching rates of iron and titanium are negligible.

Evolution of Phase Composition and Microstructure of Al_2O_3-Si-Al Composite at High Temperatures in Reducing Atmosphere

Al2 O3-Si-Al composite specimens with the size of 25 mm × 25 mm × 125 mm were prepared using fused alumina （as aggregates and fines）,ultra-fine α-Al2O3,Si and Al powders as starting materials,liquid phenol formaldehyde resin as the binder,pressing and heating at 800-1 500 ℃ for 3 h under carbon embedded condition.Evolution of phase composition and microstructure of Al2 O3-Si-Al composite during heating from 800 to 1 500 ℃ under carbon embedded condition were studied.The results show that：（1） Al4 C3,AlN and SiC are initially formed at 800-900 ℃ due to reactions of Al and Si with C or CO and N2 ; （2） at 1 000-1 300 ℃,the amounts of Al4C3,AlN and SiC increase with temperature rising and their crystals grow; （3） at 1 400-1 500 ℃,Al4 C3 and AlN disappear,and minor SiAlON crystals are observed; the nonoxide crystals develop well and they are interlaced in the corundum skeleton structure,which creates strengthening and toughening

Effects of MgO and TiO_2 on the viscous behaviors and phase compositions of titanium-bearing slag

The effects of MgO and TiO_2 on the viscosity, activation energy for viscous flow, and break-point temperature of titanium-bearing slag were studied. The correlation between viscosity and slag structure was analyzed by Fourier transform infrared（FTIR） spectroscopy. Subsequently, main phases in the slag and their content changes were investigated by X-ray diffraction and Factsage 6.4 software package. The results show that the viscosity decreases when the MgO content increases from 10.00wt% to 14.00wt%. Moreover, the break-point temperature increases, and the activation energy for viscous flow initially increases and subsequently decreases. In addition, with increasing TiO_2 content from 5.00wt% to 9.00wt%, the viscosity decreases, and the break-point temperature and activation energy for viscous flow initially decrease and subsequently increase. FTIR analyses reveal that the polymerization degree of complex viscous units in titanium-bearing slag decreases with increasing MgO and TiO_2 contents. The mechanism of viscosity variation was elucidated. The basic phase in experimental slags is melilite. Besides, as the MgO content increases, the amount of magnesia–alumina spinel in the slag increases. Similarly, the sum of pyroxene and perovskite phases in the slag increases with increasing TiO_2 content.

High-temperature electrochemical performance and phase composition of Ti_(0.7) Zr_(0.5) V_(0.2) Mn_(1.8-x)Ni_x hydrogen storage electrode alloys

The rapid development of electric vehicles demands the development of high performance nickel metal hydride battery that is able to endure high temperature. The discharge properties of Ti 0.7 Zr 0.5 V 0.2 Mn 1.8- x Ni x ( x =0.4, 0.8, 1.1, 1.4, 1.7)hydrogen storage alloys was investigated and its phase composition was analyzed using X ray diffraction. The results show that the cycling life was improved as the content of nickel increases. When x =0.4, 0.8, 1.1 and 1.4, the main phase is MgZn 2 type C14 Laves phase and the second one is cubic TiNi phase. When x =1.7, the Laves phase structure disappears. EDAS analysis shows that the increase of nickel content is effective in suppressing the dissolution of vanadium component in alloys. [

Fine structure and phase composition of Fe–14Mn–1.2C steel:influence of a modified mixture based on refractory metals

The effect of TiO;,ZrO;and Na;AlF;ultrafine powders on the fine structure and the phase composition of Fe–14Mn–1.2C steel was investigated.The introduction of the ultrafine powders into the melt influenced the grain size,the quantity,and the character of distribution of nonmetallic inclusions in the railroad frogs.The microstructure of castings was improved significantly because of the refinement of the grain structure and an increase of the grain-boundary area.After the modifying mixture was introduced into the melt,either the microtwins of one or two intersecting systems or the precipitations of ε-martensite of different types,or simultaneously the microtwins and wafers of ε-martensite,were present in each grain.

Phase Composition Analysis of TiN-AI_2O_3Synthesized from Aluminum-containing Dross and Rutile by Aluminothermic Reductionnitridation Method

TiN- Al2O3 composite powder was prepared by aluminothermic reduction- nitridation method with starting materials of aluminum-containing dross and rutile,and metallic aluminum in the aluminum-containing dross as reducer. The influences of synthesis temperature（600-1 400 ℃） and aluminum-containing dross addition（20% lower than theoretical value,theoretical value,20% higher than theoretical value,and 50% higher than theoretical value） on phase compositions and microstructure of the composites were investigated,and the reaction mechanism was analyzed. The results show that（1） TiN- Al2O3 composite powder can be synthesized under the experimental conditions; the main phases are TiN,α-Al2O3,a little bytownite,and MgAl2O4;（2）enhancing synthesis temperature or increasing aluminumcontaining dross addition favors the reaction of aluminothermic reduction- nitridation;（3） in the synthesized products,α-Al2O3 is platy or columnar; TiN is sub-micron granular,which reinforces and toughens the composite.

Self‑Assembly of Binderless MXene Aerogel for Multiple‑Scenario and Responsive Phase Change Composites with Ultrahigh Thermal Energy Storage Density and Exceptional Electromagnetic Interference Shielding

The severe dependence of traditional phase change materials(PCMs)on the temperature-response and lattice deficiencies in versatility cannot satisfy demand for using such materials in complex application scenarios.Here,we introduced metal ions to induce the self-assembly of MXene nanosheets and achieve their ordered arrangement by combining suction filtration and rapid freezing.Subsequently,a series of MXene/K^(+)/paraffin wax(PW)phase change composites(PCCs)were obtained via vacuum impregnation in molten PW.The prepared MXene-based PCCs showed versatile applications from macroscale technologies,successfully transforming solar,electric,and magnetic energy into thermal energy stored as latent heat in the PCCs.Moreover,due to the absence of binder in the MXene-based aerogel,MK3@PW exhibits a prime solar-thermal conversion efficiency(98.4%).Notably,MK3@PW can further convert the collected heat energy into electric energy through thermoelectric equipment and realize favorable solar-thermal-electric conversion(producing 206 mV of voltage with light radiation intensity of 200 mw cm^(−2)).An excellent Joule heat performance(reaching 105℃with an input voltage of 2.5 V)and responsive magnetic-thermal conversion behavior(a charging time of 11.8 s can achieve a thermal insulation effect of 285 s)for contactless thermotherapy were also demonstrated by the MK3@PW.Specifically,as a result of the ordered arrangement of MXene nanosheet self-assembly induced by potassium ions,MK3@PW PCC exhibits a higher electromagnetic shielding efficiency value(57.7 dB)than pure MXene aerogel/PW PCC(29.8 dB)with the same MXene mass.This work presents an opportunity for the multi-scene response and practical application of PCMs that satisfy demand of next-generation multifunctional PCCs.

Controllable thermal rectification design for buildings based on phase change composites

Phase-change material(PCM)is widely used in thermal management due to their unique thermal behavior.However,related research in thermal rectifier is mainly focused on exploring the principles at the fundamental device level,which results in a gap to real applications.Here,we propose a controllable thermal rectification design towards building applications through the direct adhesion of composite thermal rectification material(TRM)based on PCM and reduced graphene oxide(rGO)aerogel to ordinary concrete walls(CWs).The design is evaluated in detail by combining experiments and finite element analysis.It is found that,TRM can regulate the temperature difference on both sides of the TRM/CWs system by thermal rectification.The difference in two directions reaches to 13.8 K at the heat flow of 80 W/m^(2).In addition,the larger the change of thermal conductivity before and after phase change of TRM is,the more effective it is for regulating temperature difference in two directions.The stated technology has a wide range of applications for the thermal energy control in buildings with specific temperature requirements.

Effect of erbium doping on phase composition, mechanical and thermal properties of ZrO_(2)-based ceramics

Er_(x)Ti_(0.1)Zr_(0.9-x)O_(2-1.5 x)(x=0.04,0.05,0.06,0.07,0.08) ceramics were synthesized by a solid-state reaction method.The influence of the Er^(3+) addition on the phase composition,Vickers hardness,fracture toughness,and thermal conductivity of this ceramic material was investigated.The X-ray diffraction results reveal that the c-ZrO_(2) content increases from 1.85 vol% to 33.89 vol%,and the percentage of t-ZrO_(2) decreases from 98.15 vol% to 66.11 vol% with the increase in Er^(3+) content from 4 mol% to 8 mol%.Moreover,the addition of Er^(3+) is beneficial to the volume expansion of the unit cell.At the same time,the incorporation of Er^(3+) weakens the coordination of oxygen ions around the metal cations,resulting in a corresponding decrease in the tetragonality of the t-ZrO_(2).The Vickers hardness and fracture toughness of the Er_(x)Ti_(0.1)Zr_(0.9-x)O_(2-1.5)_(x) ceramics show increasing and decreasing trends,respectively.The thermal conductivity has a significant decline due to point defects caused by the Er^(3+) doping.The 8 ETZ ceramic exhibits the highest Vickers hardness(12.7 GPa),the lowest fracture toughness(7.6 MPa·m^(1/2)),and the lowest average thermal conductivity(1.85 W/(m·K)) in the temperature range of 200-1000℃.All of the above properties are higher than those of the Y_(2)O_(3)-stabilized ZrO_(2) ceramic.

Growth Rate,Microstructure and Phase Composition of Oxide Scales for Three Typical Steels in Simulated Continuous Casting Process

C-rowth rate, microstructure and phase composition of scale layer formed during oxidation in 56 % H2O9%O2 N2 and following continuous cooling in ambient air were experimentally investigated by means of optical microscopy, scanning electron microscopy （SEM）, energy-dispersive spectroscopy （EDS） and X-ray diffraction （XRD） for 45, 20CrMnTi and TTS443M steels respectively, to examine the effects of strand surface temperature and steel composition on the scale formation in simulated continudus casting process. The growth rates were found to be ap proximately parabolic and the calculated activation energy of TTS443M steel is much higher than those of the two other steels. For 45 and 20CrMnTi steels, the scale layers were looser and a distinct gap formed at the scale-sub strate interface at higher strand surface temperature. The dominant phases within the scale were iron oxides except for FeO · Cr2O3 phase simuhaneously existing in the oxide scale of 20CrMnTi steel. On the other hand, the scale layer formed on TTS443M steel was compact and tightly attached to the steel surface. At both lower and higher strand surface temperature, iron oxide was main phase in external layer of the scale, while chromia was dominant in inner layer with an appreciable Cr enrichment.

Computer-assisted optimization of mobile phase compositions and development distance selectivity in gradient two-step development high-performance thin-layer chromatography

A computer-assisted method is presented for optimization of mobile phase compositions and development distance in gradient two-step development HPTLC. The method is based on a system which can predict the final R(f) values for gradient two-step development from values measured using five preliminary runs. The statistical scanning method is then used for optimization, using R(f) difference as the selection criterion. The method was evaluated using a mixture of eight components. Excellent agreement was obtained between predicted and experimental results.

Evolution of microstructure and electromagnetic interference shielding performance during the ZrC precursor thermal decomposition process

A polymer-derived ZrC ceramic with excellent electromagnetic interference(EMI)shielding performance was developed to meet ultra-high temperature requirements.The thermal decomposition process of ZrC organic precursor was studied to reveal the evolution of phase composition,microstructure,and EMI shielding performance.Furthermore,the carbothermal reduction reaction occurred at 1300℃,and the transition from ZrO_(2) to ZrC was completed at 1700℃.With the increase in the annealing temperature,the tetragonal zirconia gradually transformed into monoclinic zirconia,and the transition was completed at the annealing temperature of 1500℃ due to the consumption of a large amount of the carbon phase.The average total shielding effectiveness values were 11.63,22.67,22.91,22.81,and 34.73 dB when the polymerderived ZrC was annealed at 900,1100,1300,1500,and 1700℃,respectively.During the thermal decomposition process,the graphitization degree and phase distribution of free carbon played a dominant role in the shielding performance.The typical core–shell structure composed of carbon and ZrC can be formed at the annealing temperature of 1700℃,which results in excellent shielding performance.