Sintering Temperature Research Articles

Oxygen transport mechanism and the effect of microstructure on the oxygen response behavior of an oxygen-sensitive composite Ce0.9Gd0.1O2-ẟ – La0.6Sr0.4FeO3-ẟ at high temperature

Compositions like gadolinium doped cerium oxide Ce0.9Gd0.1O2-ẟ and strontium doped lanthanum ferrite La0.6Sr0.4FeO3-ẟ, or their composites are well known in the field of fuel cell electrolyte, oxygen transporting membrane and catalytic reactor applications. This work offers insight into composite material's oxygen response characteristics, taking Ce0.9Gd0.1O2-ẟ and La0.6Sr0.4FeO3-ẟ in 70: 30 wt percent. One pot sol-gel method was employed for the powder synthesis. The powder was characterized by TG-DSC, XRD, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). FESEM-EDX and EDX-line profiling techniques were used to check the compositional homogeneity of sintered bodies. Oxygen response tests were conducted from ambient (20 % O2) to 100 % O2 concentration, using bulk samples sintered at three different temperatures, i.e., 1000, 1150, and 1250 °C at a fixed soaking time of 4 hours. The sintered specimens' apparent porosity, bulk density, surface morphology, and electrical conductivity were also examined. The sintering temperature significantly impacts response behavior as the porosity and grain size of the sintered body plays a vital role in sensing performance. The mechanism of response towards oxygen is also discussed. Sample 73–100 displayed the best performance among others. We achieved the lowest response and recovery time of 15 – 48 sec and 45 – 80 sec from a 0.60 mm thick bulk material at 950 °C. Harsh environments were intentionally created to check the reliability and reproducibility of the response data. This material could be a good candidate as an oxygen gas sensor at high temperatures owing to its good sensitivity, reliability, reversibility, and stability.

Effect of sintering temperature on the properties of titanium matrix composites reinforced with Al0·5CoCrFeNi high-entropy alloy particles

In this study, the organization and mechanical properties of the composites were analyzed at different sintering temperatures, and it was found that the local high-temperature phenomenon of discharge plasma sintering led to rapid melting and element diffusion at the junction of the high-entropy alloy particles and the Ti matrix, resulting in the formation of the interfacial layer. The increase in sintering temperature promoted close bonding between particles and element diffusion, caused lattice distortion and new phase formation, and increased the thickness of the interface layer and precipitated phase at the grain boundary. Most of the high-entropy alloy particles were dissolved when the sintering temperature reached 1050 °C. The composites were characterized by a high sintering temperature. The comprehensive mechanical properties of the composites first increased and then decreased when the sintering temperature increased, and they were optimized at 850 °C. The nanoindentation results show that the increase in sintering temperature leads to a decrease in the hardness of the high-entropy alloy particles, an increase in the hardness of the titanium matrix, and a higher hardness of the interfacial layer than that of the high-entropy alloy particles and the titanium matrix.

Hydroxyapatite coating of TiNi shape memory alloy via Electrophoretic Deposition (EPD)

ABSTRACT In this study, hydroxyl apatite (HA) as a bio-ceramic is coated on the TiNi shape memory. In this approach, Tri-ethanolamine and butanol were used as suspensions. To set up Electrophoretic Deposition (EPD) process, voltages of 20, 30 and 40 volts were applied on the cathode for 1-5 minutes. The sintering process was done in the Ar atmosphere for two hours at 800°C. SEM and XRD were used to investigate surface morphologies and phases. Obtained results showed that higher electrical currents led to generation of thicker coatings registering 105% and 12.3% improvement for weight and thickness after 6 minutes, respectively. Moreover, Transformation of HA to other calcium phosphate phases doesn’t happen at a sintering temperature of 800°C. Moreover, a uniform, homogeneous and crackles coating can be reached in the voltage of 30 volts at low sintering temperatures. This process can be utilized an alternative technique for bioactive coatings.

Predicting hardness of graphene-added Si3N4 using machine learning: A data-driven approach

This study presents a data-driven framework based on machine learning (ML) using extreme gradient boosting (XGBoost) for predicting the hardness of silicon nitride (Si3N4) ceramics reinforced with graphene. The XGBoost model takes into account various factors such as graphene type and content, characteristics of the raw Si3N4 powder, the parameters of the sintering process (sintering technique, temperature, pressure, holding time), and the characteristics of the sintered samples, i.e., the density, αβ content and Vickers hardness. The parameters that influence the Si3N4 hardness most strongly are identified, with sintering pressure, sintering time and density being the most influential. The addition of graphene content up to a certain threshold (1 wt%) has a positive impact on hardness. However, beyond that it leads to a lower density and a lower mechanical performance. Sintering parameters, particularly the sintering pressure, temperature, holding time and technique, strongly affect the density, final grain size, αβ Si3N4 composition and subsequently the hardness. The study highlights the importance of density and the densification process in achieving high hardness in Si3N4 ceramics. The developed ML model provides a valuable tool for predicting the hardness of Si3N4+graphene ceramics composites and offers insights into selecting suitable graphene type, content, and processing parameters. While the study primarily focuses on Si3N4+graphene composites, this novel approach holds promise for the in-silico design and analysis of diverse ceramic materials.

Effect of sintering temperature on the structural, morphological, optical and electrical properties of Ba1 − xLaxFe12O19

La substituted M-type Barium hexaferrite, Ba(1−x)La(x)Fe12O19, (x = 0.25 and 0.30) were synthesized using ball milling followed by heat treatment at 1150˚C and 1300˚C and the influence of sintering temperature as well as La doping were presented. X-ray diffraction, FESEM, dielectric spectroscopy, and ferroelectric measurements were performed to study the structural, morphological, dielectric, and ferroelectric properties of the prepared samples. Rietveld refinement on the X-ray diffraction measurement reveals the formation of a phase magnetoplumbite structure of barium hexaferrite only for the samples sintered at 1300˚C. The secondary phase, along with the major magnetoplumbite structure, was observed for the sample sintered at 1150˚C. Hexagonal plate-like grains of different sizes were observed, and samples sintered at 1300˚C showed large-size grains. Porosity was observed to decrease with La doping. Impedance spectroscopy reveals that Maxwell-Wagner-type polarisation occurs with the relaxation of mobile charges having long-range hopping. However, the ferroelectric property was suppressed for samples sintered at 1300˚C.

Multi-objective parametric optimization process of hybrid reinforced titanium metal matrix composite through Taguchi-Grey relation analysis (TGRA)

Hybrid titanium metal matrix composites (HTMMCs) are advanced composite materials that can be tailored to a variety of applications. Because of their decreased fuel consumption and cost, they are popular in the transportation industry. Using multi-objective optimization and Taguchi-based Grey relational analysis (TGRA), this study investigates the impact of hybrid reinforced HTMMCs synthesized using powder metallurgy on their physic mechanical properties. The research investigates reinforcements such as B4C, SiC, ZrO2, and MoS2 at various compaction pressures, milling durations, and sintering temperatures. The best powder metallurgy control parameters for HTMMC synthesis, with a milling time of 5 h, a compaction pressure of 40 MPa, a sintering temperature of 1200 °C, and a sintering time of 1 h, and a compaction time of 40 min. According to validation results, HTMMC material with optimized process parameters had experimental densities, porosities, hardness, compressive strength, and wear rates of 4.29 gm/cm3, 0.1178%, 71.53RHN, 2782.36 MPa, and 0.1519 mm3 correspondingly. The material hardness was increased by 1.99% and compressive strength by 2.87%. The use of Taguchi and GRA techniques strongly verified that the impact of milling duration and sintering temperature was the greatest of all five factors. The novel synthesized hybrid reinforcing HTMMCs outperformed pure Ti grade 5 and single and double fortified HTMMCs in terms of physic mechanical characteristics. As a result, the newly developed tetra hybrid reinforced HTMMC material is expected to be used in heavy-duty vehicles, aerospace, automobiles, maritime, and other industries.

Vacuum sintering of the self-developed Chang’E-5 lunar regolith simulant

The utilization of in-situ lunar resources through the additive manufacturing of lunar regolith (LR) has attracted considerable interest. Sintering of LR is considered a promising method for lunar construction due to its high utilization rate and excellent service stability. However, numerous studies have been carried out on Apollo series LRs with similar chemical compositions in air or inert gas atmospheres. The effects of the lunar ultra-high vacuum conditions and the complex chemical composition of LRs on the sintering process require extensive investigation. In this study, a self-developed Chang’E-5 lunar regolith simulant (LRS) with a high-Fe content was used as the only raw material to investigate its potential applicability for future lunar construction in vacuum environment. The effects of sintering temperature on the microstructure, linear shrinkage, bulk density, weight loss ratio, and mechanical and thermal expansion properties were investigated. The results show that the linear shrinkage and weight loss ratio increase with increasing sintering temperature. However, the bulk density and unconfined compressive strength (USC) initially increase and then decrease, with the sample sintered at 1075℃ giving the highest bulk density of 2.10 ± 0.03 g/cm3 and a USC of 31.19 ± 1.96 MPa. This is attributed to the transformation of the sample sintered at 1090℃ into a semi-porous material with many cracks. Furthermore, the mechanism of pore and crack formation was revealed. The coefficient of thermal expansion (CET) of the sintered samples is approximately 7×10–6°C−1, which maintains a good service stability after cyclic temperature stress from room temperature up to 200°C. Both the USC and CET of the sample sintered at 1075℃ are superior to those of common terrestrial concrete materials. This indicates that the vacuum sintering process appears feasible for the production of building materials with sufficient mechanical strength and thermal durability for lunar base construction.

Raw material design, sintering temperature optimization and development mechanism investigation of self-foaming porous bricks with high solid waste addition

In recent years, the contradiction between the huge production of municipal sludge and industrial residue and the shortage of landfill space has driven the exploration of novel effective methods to valorize these solid wastes. In this research, blast furnace slag (BFS), municipal sewage sludge (MSS) and kaolin are combined innovatively as precursor materials to manufacture self-foaming porous bricks, and the sintering behavior of bricks under different BFS doses and sintering temperatures is deeply studied to reveal the development mechanism. The results indicate that the formation of Fe2O3-hematite during sintering leads to a reddish-brown appearance of the bricks, while the generation of CaAl2Si2O8-anorthite with lower melting points helps to enhance the vitrification process. Besides, the increase in BFS dose or sintering temperature has significant impacts on the evolution of the brick physicochemical properties. This occurs because changing the dose of BFS or sintering temperature can obviously regulate the internal morphological characteristics of bricks, such as particle consolidation, pore size and structural compactness. Among them, large-sized pores are considered as the weak areas of mechanical strength, which is also the responsibility for the worst compressive strength of bricks sintered at 1300 °C. Finally, under the optimal sintering conditions of 15 % BFS dose and 1250 °C sintering temperature, the compressive strength, water absorption, apparent porosity, bulk density and linear shrinkage of the resulting brick are 65 MPa, 0.45 %, 2.50 %, 2.34 g/cm3 and 19.56 %, respectively. Overall results demonstrate that using recycled sludge and waste slag in brick manufacturing can produce products with desired performance, providing preferable solutions for solid waste valorization and sustainable brick production.

Effect of Nb2O5 doping on low-temperature sintering of TiO2-Al2O3 ceramics

This study investigates the effects of Nb2O5 as a dopant in TiO2–Al2O3 ceramics to lower sintering temperature and enhance performance, including the physical, mechanical, and dielectric properties of the ceramics at sintering temperatures 1250 °C–1350 °C. Specifically, TiO2–Al2O3 ceramics doped with 1.5 wt% Nb2O5 and sintered at 1350 °C exhibit remarkable density 94 %, compressive strength 1372 MPa, and abrasion resistance 1.36 × 10−4 mm3/N·m, surpassing those of pure alumina ceramics. This improvement is attributed to enhanced grain boundary diffusion and strain energy resulting from Nb5+ cation substitution. The incorporation of Nb2O5 in TiO2–Al2O3 ceramics reduce sintering temperatures by 150–200 °C. The dielectric constant of TiO2–Al2O3 ceramics doped with 1.5 wt% Nb2O5 sintered at 1350 °C is found to be 13.4, with a dielectric loss of 2.56 × 10−2 and insulation resistance 7.3 × 1012 Ω. Nb2O5 is an effective additive for reducing sintering temperatures in Al2O3 based ceramic.

Microstructure evolution and properties of textured, Pb(Zr1/2Ti1/2)O3-Pb(Zn1/3Nb2/3)O3–Pb(Ni1/3Nb2/3)O3 ceramics with plate-like BaZr0.1Ti0.9O3 template

[001]C-textured ceramics of 0.83Pb(Zr1/2Ti1/2)O3-0.11Pb(Zn1/3Nb2/3)O3- 0.06Pb(Ni1/3Nb2/3)O3 with 10 wt% plate-like BaZr0.1Ti0.9O3 templates (PZNNT-BZT) were manufactured using the template grain growth (TGG) method. With various sintering temperatures and holding times, the microstructure, domain structure and electric properties of textured and non-textured samples were studied. The PZNNT-BZT textured ceramics obtained the desired piezoelectric performance (d33 = 318 pC/N, TC = 230 ℃, d33×g33 = 10174×10−15 m2/N) with the textured fraction of 63 %. Furthermore, the analysis and observation were conducted about the correlation mechanism between phase structure, domain configuration, electrical performance, and energy harvesting properties of PZNNT-based ceramics. From kinetic and thermodynamic viewpoints, the evolution of the oriented grains and texture fraction variation were understood, and this led to suggestions that BaZr0.1Ti0.9O3 could serve as a potential template for PZT-based textured ceramics with a high textured fraction.

Effect of sintering temperature and doping content on phase evolution and microstructure of doped UO2 ceramics

ZrO2-doped UO2 ceramics have been considered as a promising high performance nuclear fuel in LWR due to its desirable properties. ZrO2-doped UO2 ceramic fuel samples with different contents of ZrO2 (20 wt%, 25 wt% and 30 wt% ZrO2, equivalent to 35.4 mol%, 42.3 mol% and 48.4 mol%, respectively) were prepared by pressureless sintering at various temperatures (1550 ℃, 1650 ℃ and 1750℃, respectively) for 4 h in a hydrogen reducing environment. Phase evolution and microstructure of as-sintered ZrO2-doped UO2 ceramic samples were investigated by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS), respectively. Results show that there exists coexistence of uranium-rich U1-xZrxO2 phase with face-centered cubic (FCC) structure and zirconium-rich Zr1-yUyO2 phase with tetragonal structure in the 20 wt% ZrO2-doped UO2 ceramic sample when the sintering temperature is lower than 1650 ℃, while the UO2 and ZrO2 will form a single U1-xZrxO2 solid solution after sintering at 1750℃ for 4 h with the ZrO2-doped UO2 ceramic samples containing 25 or 30 wt% ZrO2, respectively. The significant differences of phase structure and ionic radius between ZrO2 and UO2 and the high atomic diffusion barrier are the main reasons that it is difficult to form a single solid solution for UO2-ZrO2 ceramic samples sintered at low temperature.

Two birds with one stone: Benefits of sintering additives on sinterability and electrical property of new protonic ceramic fuel cell electrolyte SrSn0.8Sc0.2O3-δ

Various approaches have been developed to address the challenges of difficult densification in traditional BaZrO3-based and BaCeO3-based protonic ceramic fuel cells (PCFCs) electrolytes. The addition of sintering additives, the most widely used approach, has been found to potentially compromise electrical performance while improving sinterability in traditional sintering. Recently, SrSn0.8Sc0.2O3-δ (SSS) has emerged as a promising proton-conductor material; however, there is still space for improvement in its electrical and sintering properties. In this study, a systematic investigation was conducted into the effect of sintering additives (NiO, ZnO, CuO) on the electrical performance of the new proton conductor SSS. Notably, SSS-1wt%NiO was found to decrease the sintering temperature from 1600 °C to 1400 °C (reaching 92 % relative density) and increase protonic conductivity from 2.61 × 10−3 S cm−1 to 3.06 × 10−3 S cm−1 at 600 °C, without any increase in electronic conductivity. This demonstrates a synergistic beneficial effect on both sinterability and electrical properties. Furthermore, the Ni-SSS|SSS-1wt%NiO|SSS-BCFZY single cell achieved the highest peak power density (528.5 mW cm−2 at 800 °C), surpassing all the other SSS-based single cells. Therefore, the addition of NiO to the SSS electrolyte demonstrates the significant sintering and electrical properties of SSS, proving evidence for the potential commercial application of SSS electrolytes for PCFCs.

Reactive Synthesis for Porous (Mo2/3Y1/3)2AlC Ceramics through Mo, Y, Al and Graphite Powders.

Through an activation reaction sintering method, porous (Mo2/3Y1/3)2AlC ceramics were prepared by Mo, Y, Al, and graphite powders as raw materials. The phase composition, microstructure, element distribution, and pore structure characteristics were comprehensively studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), Archimedes method, and bubble point method. A detailed investigation was conducted on the influence of sintering temperature on the phase composition. Possible routes of phase transition and pore formation mechanisms during the sintering process were provided. The experimental results reveal that at 650-850 °C, transition metals react with aluminum, forming aluminum-containing intermetallics and a small amount of carbides. At 850-1250 °C, transition metals collaborate with graphite, producing transition metal carbides. Then, at 1250-1450 °C, these aluminum intermetallics interact with transition metal carbides and remaining unreacted Y, Al, and C, yielding the final product (Mo2/3Y1/3) 2AlC. Simultaneously, the pore structure alters correspondingly with the solid-phase reaction at different reaction temperatures.

Microstructure, mechanical and corrosion property of neutron and γ-ray shielding (Gd2O3+W)/Al composites

In this study, a neutron and γ-ray absorbing (Gd2O3+W)/Al composite was fabricated by vacuum sintering. Firstly, through Monte Carlo Neutron and Photo Transport Code (MCNP) calculations, the content of Gd2O3 and W in the composite was determined to be 10 wt% and 25 wt%, respectively. Then, the influence of sintering temperature and sintering time on the microstructure, density, compression properties and electrochemical corrosion behavior of the (Gd2O3+W)/Al composites were investigated. The results indicate that sintering temperatures below 600 °C and sintering times shorter than 2 h led to insufficient density of the composite. Conversely, sintering temperatures above 600 °C and sintering times longer than 2 h caused W to agglomerate, resulting in a decrease in the density of the composite and a deterioration of its electrochemical performance. Therefore, the optimal sintering temperature and sintering time for the (Gd2O3+W)/Al composites were determined to be 600 °C and 2 h, respectively. Finally, the immersion corrosion performance in H3BO3 solution of the composite fabricated by the optimal process parameters was studied in detail. It was found that pitting was the main corrosion form of the (Gd2O3+W)/Al composite, and an oxidation film mainly composed of Al2O3 was formed on the surface.

Novel Sol-Gel Synthesis Route for Ce- and V-Doped Ba0.85Ca0.15Ti0.9Zr0.1O3 Piezoceramics.

To meet the current demand for lead-free piezoelectric ceramics, a novel sol-gel synthesis route is presented for the preparation of Ba0.85Ca0.15Ti0.9Zr0.1O3 doped with cerium (Ce = 0, 0.01, and 0.02 mol%) and vanadium (V = 0, 0.3, and 0.4 mol%). X-ray diffraction patterns reveal the formation of a perovskite phase (space group P4mm) for all samples after calcination at 800 °C and sintering at 1250, 1350, and 1450 °C, where it is proposed that both dopants occupy the B site. Sintering studies show that V doping allows the sintering temperature to be reduced to at least 1250 °C. Undoped BCZT samples sintered at the same temperature show reduced functional properties compared to V-doped samples, i.e., d33 values increase by an order of magnitude with doping. The dissipation factor tan δ decreases with increasing sintering temperature for all doping concentrations, while the Curie temperature TC increases for all V-doped samples, reaching 120 °C for high-concentration co-doped samples. All results indicate that vanadium doping can facilitate the processing of BCZT at lower sintering temperatures without compromising performance while promoting thermal property stability.

Enhanced fracture toughness of high entropy boride by adding SiC

The effect of SiC content (10 vol%, 20 vol% and 30 vol%) and sintering temperature (1800 °C, 1900 °C and 2000 °C) on the microstructure and mechanical properties of high entropy boride-silicon carbide (HEB-SiC) composites were systematically investigated in this work. The densification was gradually increased with the increase of SiC content and sintering temperature. More specially, the densification of HEB-30 vol% SiC composite obtained at 2000 °C was as high as 99.1 %. As for the mechanical properties, the dense HEB-30S-2000 composite possessed the highest fracture toughness (5.24 MPa m1/2) and Vickers hardness (28.5 GPa). The above significantly enhanced fracture toughness was closely pertained to the fracture modes adjusting. In details, after the addition of SiC, the branching and bridging of crack, the rupture of large SiC grain, and the deflection of crack existing near the HBE matrix and SiC particles jointly promote the improvement of fracture toughness. Besides, the Vickers hardness increased linearly with the relative density increasing. A simplified equation was established, which could effectually reflect the linear connection between the Vicker hardness and relative density (SiC content) of HEB-SiC composites. It will certainly play an important guiding role in the further development of HEB-SiC composites.

Spark Plasma Sintering of Cu-Ti-Ni Ternary Alloy: Microstructural, Thermal and Electrical Properties

High strength and good conductivity are both critical parameters for copper-based alloys for electrical and other technological applications. This study is aimed to produce copper alloys and metal matrix composites (MMCs) with enhanced physical properties. Cu-Ti-Ni ternary alloys and MMCs samples were sintered at 600 to 700°C using spark plasma sintering (SPS), with a heating rate of 100°C/minutes, uniaxial pressure of 50 MPa, and a holding time of 10 minutes. Scanning electron microscopy (FE-SEM) was used to examine the microstructure, while the relative densities of the composites were obtained via the Archimedes Principle method. A four-point probe and differential thermal analyzer (DTA) obtained electrical resistivity and thermal properties. The results indicated that the sample density nominally increases with sintering temperature but decreases with aluminium nitride additions. The electrical conductivity increases with the sintering temperature and AlN nanoparticle content. Distinct phase changes were observed from the DTA, occurring with the addition of AlN.

A novel high hardness and low loss Mg5Ga2Sn2O12 ceramic with spinel-structure

Inorganic oxides with a spinel structure play an indispensable role in various applications because of their stability and exceptional performance. This study prepared Mg5Ga2Sn2O12 ceramics using the solid-state method. TEM analysis reveals that the ceramics show local lattice distortions. When the sintering temperature is 1480 °C, the relative density and Vickers hardness of Mg5Ga2Sn2O12 ceramics are 96.8 % and 12.58 GPa, respectively. The Mg5Ga2Sn2O12 ceramics exhibit optimum microwave dielectric properties, with εr = 8.57, Q × f = 138,769 GHz, and τf = −24.7 ppm/°C. Far-infrared fitting shows that the vibration mode in the low-wave number region has a significant influence on the dielectric properties of ceramics. The P–V−L theory indicates that the Sn–O bond has the most significant influence on εr and Q × f. Given these advantages, Mg5Ga2Sn2O12 ceramics hold promise for applications in low-loss dielectric materials.

Effect of desert-sand replacing pure SiO2 on crystallization, densification and properties of cordierite glass-ceramic

Idle desert sand was utilized to replacing pure SiO2 in raw materials to synthesize cordierite glass-ceramics. The effects of desert sand addition on sinterability, phase transformation, microstructure, and mechanical and thermal properties of the glass-ceramics were studied. Results show that glass transition temperature and the crystallization temperatures of glass to μ-cordierite and further to α-cordierite were all monotonously decreased with an increase of the replacement from 10 wt% to 90 wt%. Densification of the glass powder compacts started from 900 °C and was improved with increasing the replacement of desert sand and sintering temperature. The highest bending strength of 133.6 MPa and hardness of 936.7 HV were occurred at 90 wt% replacement when sintered at 1000 °C and 1100 °C for 2 h respectively; the lowest thermal expansion coefficient of 1.92 × 10−6/°C was achieved by a 50 wt% replacement and sintering at 1100 °C for 2 h. Desert sand addition not only introduces main compositions of SiO2, Al2O3, and MgO but also introduces nucleation agents of Fe2O3 and TiO2 and fluxes of Na2O, K2O, and CaO. These impurities had significant effect on improvement of the crystallization, densification, and properties of products. This eliminates the need for nucleation agents and fluxes that are necessary in the case of using pure oxides and minerals as raw materials.

Polarization at the compositional interface in Nb-doped metastable TiO2-SnO2 solid solutions

Polarization architecture was incorporated into metastable Nb-doped TiO2-SnO2 to deliver electron accumulation at the localized TiO2-SnO2 compositionally fluctuating interface. Specimens were quenched from various holding temperatures to ambient temperatures in air to avoid bimodal decomposition into TiO2 and SnO2 endmembers. At the lowest sintering temperature of 1,400 °C, the mixed phase containing TiO2- and SnO2-rich compositions existed as an intermediate state to the single-phase solid solution. The phase boundary became more ambiguous with increasing sintering temperatures, and the compositional fluctuation size reduced to single nanometers at 1,500 °C. The permittivity due to the interfacial polarization, ε interface, increased steadily with increasing sintering temperature. The larger ε interface values at higher temperatures are attributed to the greater density of the compositionally fluctuating phase interface, which leads to greater electron accumulation at the energy barrier between the two semiconducting layers.