Containerless Method Research Articles

Upconversion photoluminescence and optical temperature probe of Er3+/Yb3+ co-doped LAZT glass prepared by containerless aerodynamic levitation method

xEr3+/yYb3+ co-doped La2O3-Al2O3-ZrO2-TiO2 ([30-(30/88) × (x + y)]La2O3-[58-(58/88) × (x + y)]Al2O3-4ZrO2-8TiO2: x mol% Er2O3/y mol% Yb2O3, x = 2 mol%, and y = 4, 8, 12, 16, 20 mol%, abbreviated as: LAZT: xEr/yYb) glasses were synthesized using a containerless aerodynamic levitation technique. The maximum phonon energy, fluorescence performance and optical temperature measurement performance of the prepared glasses were studied. Raman test shows that the maximum phonon energy of all glasses is less than 355 cm−1, in which the low phonon energy can provide an excellent internal environment for the induction of fluorescence effects. Under excitation at 980 nm, all samples exhibit noticeable red emission peak centering at 662 nm and feeble green emission peak centering at 549 nm at room temperature. The luminous intensity reaches the highest value at x = 2 mol% and y = 12 mol%, at which the concentration quenching phenomenon occurs. The fluorescence mechanism of LAZT: xEr/yYb involves a double-photon process, in which the energy transfer process (ET) accounts for the main part and the excited state absorption process (ESA) accounts for the secondary part. The fluorescence intensity ratio (FIR) can be used for temperature sensing, and the absolute sensitivity FIR reaches maximum value of 1.3 × 10−2 K−1 at 79 K. These results indicate that the LAZT: 2Er/12Yb glass is expected to become a candidate material for non-contact optical temperature probe.

Heterogeneous nucleation and dendritic growth of niobium under containerless electrostatic levitation

With the containerless electrostatic levitation method, the undercooling level and nucleation solidification mechanism of niobium samples of 99.7% and 99.95% in purity were comprehensively studied. The classical nucleation theory was used to measure and calculate the thermophysical and thermodynamic characteristics associated with the nucleation and solidification procedure. The measurement results show that the maximum undercooling of experimental samples is 455.7 K, while the hyper cooling limit of the niobium is derived at 739 K. The most probable nucleation undercooling, pre-exponential factor, nucleation activation energy, solid/liquid interface free energy, and the critical nucleus radius are determined. The dendrite growth velocity has a powerful relationship with undercooling, and the dendritic growth velocity of liquid niobium reaches 42.1 m/s at the undercooling of 454 K. The effect of the anisotropy of surface energy is taken into account, and the forecast results display excellent consistency with the experimental ones.

Impact of non-bridging oxygens on the thermal, electrical and optical properties of germanate glasses and exploration of the germanate anomaly

In this study, we successfully prepared quaternary germanate glasses (Bax/3Srx/3Cax/3)Ge(1-x)O3 (x = 0.1–0.5) using a containerless solidification method. The structure of the germanate amorphous materials was characterized using techniques such as XRD, SEM, TEM and Raman. We evaluated the thermodynamic properties of the amorphous materials using differential scanning calorimetry and investigated their crystallization activation energies. In terms of application performance, we measured electrical conductivity and impedance spectra for the electrical properties, while the optical properties were assessed through the refractive index and transmittance. The results revealed that the (Ba0.2/3Sr0.2/3Ca0.2/3)Ge0.8O3 system represented the germanium anomaly point. Due to the highest number of ternary rings and the most compact structure within this system, the values of density, glass transition temperature, refractive index, and bandgap all reached their maximum. As the content of alkaline earth oxides increased, the glass network structure gradually fractured, leading to an increase in non-bridging oxygens and corresponding changes in properties.

(Keynote) Experimental Insights for Extra-Terrestrial Application of Molten Oxide Electrolysis

Molten oxide electrolysis (MOE) has been considered for several decades for oxygen generation from extra-terrestrial oxides. It consists in the electrolytic decomposition of the rocks or soils, which are mixture of the common earth oxides (silica, iron oxide(s), alumina, magnesia...). Therein the oxides mixture is acting as the electrolyte, in the molten state. The target anodic product is oxygen gas, and the cathodic product is a metal. In one version of MOE, the temperature is high enough to sustain the production of a liquid metal, offering the opportunity to conceive a fully continuous process thanks to periodic tapping of the cathodic product. A key attribute of such approach is the high current density (productivity) that can be anticipated thanks to the high concentration of oxygen and metal present in the electrolyte. This leads to electrochemical engineering questions that are not commonly discussed in other electrolysis methods. This presentation offers to review some of the prior findings related to the underlying thermodynamic of the process, as well as the oxygen evolution and transport phenomena that support the development of MOE. Recent findings combining a container-less method and advanced electrochemical techniques will be presented.

Dendrite microstructure formation and enhanced toughness in high‐entropy REAlO3–RE2Zr2O7 eutectic oxide

AbstractIn this study, complex GdAlO3–Gd2Zr2O7 and high‐entropy REAlO3–RE2Zr2O7 (RE = Nd, Sm, Gd, Eu, and Dy) composites with an equiaxed dendrite structure at eutectic composition are successfully fabricated using a gas levitation containerless solidification method. The unique microstructure of the composites is characterized, and the evolution process of the dendritic structure is explained. The formation of dendrites at eutectic composition is attributed to the rapid cooling induced by the shutoff of lasers and the homogeneous temperature field and nucleation achieved through gas levitation. The GdAlO3–Gd2Zr2O7 and high‐entropy oxide composites exhibit enhanced fracture toughness compared to the bulk samples fabricated by solid‐state sintering methods. The fracture toughness increases by 44% for GdAlO3–Gd2Zr2O7 bulk sample and 34% for high‐entropy REAlO3–RE2Zr2O7 bulk sample, which can be attributed to the complicated interfaces introduced by the equiaxed dendritic microstructure and the high thermal mismatch stress between two phases. Additionally, the high‐entropy REAlO3–RE2Zr2O7 oxides exhibit excellent high‐temperature stability, with no significant change in dendritic microstructure or fracture toughness even after holding at 1573 K for 100 h. These findings suggest the potential of high‐entropy eutectic oxide ceramics with dendrite microstructure for advanced engineering applications.

Photoinduced self-assembly of nanocrystals inside Al2O3-Lu2O3 glass

The femtosecond laser direct writing technique can allow spatially selective crystallization with suppression of thermal conduction effects. In the case of Al2O3-R2O3 (R = Y, Dy) glass, the polarization-dependent periodic nanostructure with crystallization is self-assembled, however, the formation mechanism of self-assembled nanocrystals in glass remains to be clarified. We focused on Al2O3-Lu2O3 glass prepared by a containerless laser melting method and demonstrated the formation of a nanograting with crystallization by femtosecond laser irradiation. Polarized luminescence measurements of the crystallized region by the pulse bursts with a controllable number of pulses reveal that luminescence anisotropy increased at more than 50 pulses in a burst, suggesting the formation of the nanograting. We have also followed the time variation of birefringence by polarized light imaging to evaluate the time scale for the formation of nanogratings with crystallization.

Luminescence performance of Eu3+ doped 25La2O3-60Al2O3-15ZrO2 glass prepared by containerless method

Rare-earth metal Eu doped glass 25La2O3-60Al2O3-15ZrO2:xEu3+ (x = 0.1 wt%, 0.5 wt%, 1.0 wt%, 3.0 wt% and 5.0 wt%) was prepared by gas suspension containerless laser melting technology, which is transparent and has sphere ball shape. The glass shows excellent thermal stability although the temperature difference ΔT between crystallization initiation temperature To and glass transition temperature Tg (ΔT=To-Tg) is just between 48.6 ℃− 64.9 ℃, showing low glass forming ability and being difficult to prepare glass by traditional melt-quenching method. The Eu-doped glass preserves rather high transparency, and presents enhanced mechanical performance due to the Eu3+ doping, which improves glass network connectivity. Strong orange emission peak centered at 605 nm and red emission peak at 696 nm, and weak yellow emission peak centered at 582 nm and red emission peak at 646 are engendered under the excitation of 394 nm light, attributing to the 5D0→7F2, 5D0→7F4, 5D0→7F1, and 5D0→7F3 electron energy level transitions of Eu, respectively. The 25La2O3-60Al2O3-15ZrO2:xEu3+ phosphor glass has strong nearly standard red light with high color purity, which presents excellent candidate for red luminescent phosphor and shows potential application in white-light-emitting diode.

Unraveling the initial steps of the ignition chemistry of the hypergolic ionic liquid 1-ethyl-3-methylimidazolium cyanoborohydride ([EMIM][CBH]) with nitric acid (HNO3) exploiting chirped pulse triggered droplet merging.

The composition of the products and the mechanistic routes for the reaction of the hypergolic ionic liquid (HIL) 1-ethyl-3-methylimidazolium cyanoborohydride ([EMIM][CBH]) and nitric acid (HNO3) at various concentrations from 10% to 70% were explored using a contactless single droplet merging within an ultrasonic levitation setup in an inert atmosphere of argon to reveal the initial steps that cause hypergolicity. The reactions were initiated through controlled droplet-merging manipulation triggered by a frequency chirp pulse amplitude modulation. Utilizing the high-speed optical and infrared cameras surrounding the levitation process chamber, intriguing visual images were unveiled: (i) extensive gas release and (ii) temperature rises of up to 435 K in the merged droplets. The gas development was validated qualitatively and quantitatively with Fourier Transform Infrared Spectroscopy (FTIR) indicating the major gas-phase products to be hydrogen cyanide (HCN) and nitrous oxide (N2O). The merged droplet was also probed by pulsed Raman spectroscopy which deciphered features for key functional groups of the reaction products and intermediates (-BH, -BH2, -BH3, -NCO); reaction kinetics revealed that the reaction was initiated by the interaction of the [CBH]- anion of the HIL with the oxidizer (HNO3) through proton transfer. Computations indicate the formation of a van-der-Waals complex between the [CBH]- anion and HNO3 initially, followed by proton transfer from the acid to the anion and subsequent extensive isomerization; these rearrangements were found to be essential for the formation of HCN and N2O. The exoergicity observed during the merging process provides a molar enthalpy change up to 10 kJ mol-1 to the system, which could be sufficient for a significant fraction of the reactants of about 11% to overcome the reaction barriers in the individual steps of the computationally determined minimum energy pathways.

The Surface Tension and Density of Molten Sc_{2}O_{3}, La_{2}O_{3}, Y_{2}O_{3}, Al_{2}O_{3}, and MgO Measured via a Pendant Droplet Method

A thermal imaging furnace (TIF) was used to study the physical properties of molten Sc_{2}O_{3} , La_{2}O_{3}, Y_{2}O_{3}, Al_{2}O_{3} and MgO via a containerless method. The density and surface tension of molten droplets of Sc_{2}O_{3} , La_{2}O_{3}, Y_{2}O_{3}, Al_{2}O_{3}, and MgO suspended from their own solid were measured in situ using live video under a range of oxygen partial pressures (1rightarrow 10^{-6} atm O_{2}). To the best knowledge of the authors, this is the first time the surface tension and density of molten MgO and Sc_{2}O_{3} have been reported. A relationship between molten oxide surface tension and the enthalpy of vaporization is proposed, and a comparison is drawn between the oxide properties and similar relationships previously established for liquid metals.

ЕКОЛОГІЧНА ОЦІНКА СТАНУ ПОВОДЖЕННЯ З ТВЕРДИМИ ПОБУТОВИМИ ВІДХОДАМИ В МІСТІ УМАНЬ

The study of municipal solid waste management was carried out on the example of the city of Uman, the features of the municipal waste collection were considered. One of the promising utilization methods of the municipal waste organic component is proposed — anaerobic fermentation with subsequent composting of the resulting products. Urban population growth, industrialization, urbanization and economic prosperity lead to an increase in municipal solid waste (MSW). The aim of the work was to consider the characteristics of municipal solid waste management using the example of the city of Uman; inspect the features of collecting municipal waste; consider a separate collection system; identify problems and possible solutions. According to the statistics of Uman city council, 73-75 tons of municipal waste per day are delivered to the landfill. The control is carried out on the composition of the waste entering the landfill. Sorting takes place using a sorting line, which was put into operation in October 2016. Removal of municipal solid waste from the residential sector is carried out according to the schedule. The waste from the private sector of the city is removed during the day. Transportation (transport) of municipal waste is carried out by specially equipped vehicles. On the plots of the private residential sector, the collection of municipal waste is carried out by containerless and container methods. The containerless method is used in those areas of private building, where the possibility of the garbage truck's driving and its maneuvering are limited. Analysis of the current state of municipal solid waste management in the city of Uman showed that the main reasons for the increase in the volume of environmental pollution due to municipal solid waste is the lack of a high-quality management system in the field of MSW management, and especially the outdated waste collection and transportation scheme. The state of MSW management does not meet modern requirements. At the landfill, as a result of the introduction of the technology for the production of biogas from municipal solid waste, it is possible to obtain marketable products — biogas and compost. The city can receive income from the use of biogas as an alternative source of energy for heating buildings or from its consuming by the population. For the city of Uman, the volume of biogas formation at the MSW landfill in 2018 would have amounted to 5,441,280 m3, and in 2019 – 5,424,930 m3.Thus, it is possible to obtain significant volumes of biogas for the production of both heat and electricity. As a result of the study, recommendations were developed to improve the system for collecting municipal waste in the city of Uman. One of the promising utilization methods of the municipal waste organic component in the city of Uman is anaerobic fermentation followed by composting of the resulting products.

Investigation of optical and thermal properties in Er3+-doped Ga2O3-La2O3-Ta2O5 glasses fabricated by containerless solidification

55Ga2O3-(35-x)La2O3-10Ta2O5-xEr2O3 transparent and bulk glasses were successfully synthesized by a containerless processing method. The effects of Er3+ concentration on thermal stability and optical properties were studied in detail. The prepared glasses exhibited high glass-transition temperature (Tg> 798 °C) and goodo resistance to crystallization (ΔT > 134 °C) by differential thermal analysis (DTA). Moreover, the detailed crystallization kinetics of 33La2O3-55Ga2O3-10Ta2O5-2Er2O3 glass was investigated, and the activation energy (E) and the frequency factor (v) of crystallization were gained by means of Kissinger method. The refractive indices were higher than 1.94 as well as the Abbe numbers were greater than 31. The transmittance spectra showed a wide transparent window ranging from 280 nm to 7.5 µm and the prepared glasses performed high infrared transmittance of nearly 80.5%. Two intense emissions centered at 1535 nm and 2700 nm could be observed when the glasses were excited by a 980 nm laser, corresponding to the Er3+ ions: 4I13/2→4I15/2, 4I11/2→4I13/2 transitions, respectively. By fitting the decay curves, the highest lifetime of 4I13/2 level could be evaluated to be 7.49 ms. Finally, a reasonable luminescence mechanism of down-conversion was proposed systematically.

A new sight into the glass forming ability caused by doping on Ba- and Ti-site in BaTi2O5 glass

La- and Nb-doped BaTi2O5 (BT2) spherical glasses were prepared by a containerless aerodynamic levitation method and their glass-forming regions were established. It is found that La-doping on the Ba-site (network-modifier) and Nb-doping on the Ti-site (network-former) show distinct difference in the glass-forming region: less than 10 % La can replace Ba whereas 40 % Nb can incorporate into BT2 glass. The distinction in glass-forming ability induced by La- and Nb-doping is discussed mainly from the structural arrangement of the glass. Raman spectroscopy analysis shows that La-doping elongates the short Ti–O bonds in the distorted [TiO5] polyhedra and thus relaxes the network. Nb-doping introduces [NbO6] polyhedra into BT2 and there exists a critical doping level (20 %), below which incorporation of Nb into BT2 relaxes the [TiOn] polyhedra by shortening the long Ti–O bond and above which [NbO6] starts to participate in the network skeleton construction resulting in a dramatic change in the glass structure, which is supported by the dramatic change in the exothermic peak on the DTA curves. This work triggers the speculation that the network-modifiers in BT2 glass possess a very important role in the structure of network-former skeleton than those in glasses based on traditional network-former oxides such as SiO2, GeO2 and B2O3, which may provide a useful strategy for modifying the properties of these novel glasses by chemical doping.

Thermophysical Properties of Advanced Ni‐Based Superalloys in the Liquid State Measured on Board the International Space Station

Advanced nickel‐based superalloys combine excellent high‐temperature mechanical strength, creep resistance, and toughness, and therefore find applications in next‐generation aircraft engines and turbines for land‐based power generators. The related fabrication processes are complex, time consuming, and costly, making it necessary to perform supporting computer simulations of the heat and material flow in the melt before and during crystallization. Such models are based on reliable thermophysical property data in the solid and liquid phase. However, measurements of surface‐ and volume‐dependent properties, such as liquid surface tension, viscosity, and specific heat of these complex liquid metal alloys, are very challenging, due to the melts high chemical reactivity at temperatures of interest. The method of choice is electromagnetic levitation, a containerless method. The measurements of surface tension, viscosity, mass density, and specific heat capacity, performed in the electromagnetic levitator (EML) on board the Space Laboratory Columbus in the International Space Station (ISS), are presented and discussed.

High hardnesses of Tm3+-doped La2O3-Al2O3 luminescent glasses fabricated by containerless solidification

A series of colorless and transparent (28-x)La2O3-72Al2O3:xTm3+ (x = 0, 1, 1.5, 2, 3) luminescent glasses were successfully prepared by the containerless method. The effects of Tm3+ substitution on the physical, thermal, optical and photoluminescence properties of La2O3-Al2O3 glasses were investigated. X-ray diffraction confirmed the amorphous natures of the as-prepared glasses. Excitated at 354 nm, La2O3-Al2O3:Tm3+ glasses emitted blue luminescence at 457 nm, corresponding to the 1D2→3F4 transition of Tm3+. These glasses showed high Vicker's hardnesses (7.2–8.8 GPa), and excellent thermal stabilities (Tg: 840–851 °C), which were both augmented with increasing content of Tm3+. They also exhibited high transmittances in a wide window ranging from 220 nm to 8.9 μm. In conclusion, the substitution of Tm2O3 for La2O3 increased the Vicker's hardness, thermal stability and transmittance window of La2O3-Al2O3 glasses, allowing potential applications to optical devices in the visible to infrared region.

Evaporation of droplet in mid-air: Pure and binary droplets in single-axis acoustic levitator.

Acoustic levitation method (ALM) is a container-less processing method with applications in various fields, including material processing, biology, and analytical chemistry. Because it is a container-less processing technique, ALM could prevent nucleation and contamination of materials being processed via contact with a container wall. It is well-known that evaporation of a sample is an important process in container-less processing of materials; however, the mechanism of evaporation in multicomponent droplets in a single acoustic levitator is still unclear. Thus, we evaluate and understand the evaporation of an acoustically levitated multicomponent droplet and manipulate the evaporation process of the sample in this study. Specifically, we investigate the evaporation process of pure and multicomponent droplets using container-less processing experimentally. The evaporation processes and temporal evolution of the surface temperature of a multicomponent droplet were evaluated using a high-speed camera and radiation thermometer, respectively. We used water, ethanol, methanol, hexane, acetone, pentane, and binary solutions (solution of 25 wt%, 50 wt%, and 75 wt% ethanol, methanol, and acetone, respectively) as test samples to study the effect of saturated vapor pressure on evaporation. Ethanol, methanol, and acetone droplets evaporate in two different stages. It was observed that the water vapor in the air condensed during the evaporation process of these water-soluble droplets; hence, our experimental data did not agree with the theoretical prediction in accordance with the d2 law. Nevertheless, the evaporation behavior in the first stage of evaporation was consistent with the theoretical prediction. Furthermore, for binary droplets, as the concentration of the resultant solution increased owing to evaporation, the transition time from the first to the second stage of evaporation also increased. Based on these observations, estimation equations for binary droplets were developed to ensure that the experimental and theoretical values were in good agreement.

Radiative thermal conduction of molten tin sulfide estimated from its optical emission spectrum

Molten semi-conductors have potential utility in thermoelectrics or heat-management at high temperature (900 °C and above), though their development requires further analysis of their thermal conduction mechanisms, in particular radiative heat-transfer. Using a container-less method based on the floating zone furnace, the optical emission properties of a pendant droplet of molten tin sulfide (SnS) are investigated in the UV–visible (200–850 nm) and near IR (900–2050 nm) ranges. The emissivity results suggest a low emissivity for molten SnS at the peak of radiation for the temperature range of 890–950 °C. Corresponding estimates of radiative thermal conductivity suggest its minor contribution to the overall thermal conduction of molten SnS.

In-situ observation of the structural change in MgO-B2O3-SiO2 glass at high pressure and the permanent structural change

A 41.6MgO-27.1B2O3-31.2SiO2 glass was synthesized by container-less levitation method. B K-edge X-ray absorption near edge structure (XANES) spectroscopy was used to quantify the coordination of boron in the as-made glass, resulting in ~72% of boron in 3-fold coordination. Raman spectroscopy indicated that the glass structure includes depolymerized borate units, which are pyroborate (B2O54−) and ring and/or chain-type metaborate (B3O63−, (BO2O−)∞) groups. The structural changes in the glass under hydrostatic condition were investigated by high-pressure Raman spectroscopy within a diamond anvil cell at pressures up to 8.5 GPa. On the borate structure, metaborate groups decreased with pressure. In contrast, triborate groups, which include tetrahedrally coordinated boron and have a fully polymerized borate network, increased; suggesting that the coordination transformation of B and polymerization were induced via compression. However, the modification of the borate structure units seems to be reversible at least up to 8.5 GPa. As for the silicate network, Q0 and Q1 structures were responsible to compression. Specifically, Q0 could be replaced by Q1 with elevating pressure, which means that the silicate network becomes polymerized with pressure. Whereas, structure of glass samples recovered from the pressure higher than 5 GPa displayed depolymerized silicate network, as dissociation of Q2 to Q1. The observed structural changes in the silicate network implied a partial change of the coordination number of Si4+ ions, which can be enhanced by the presence of a modifier cation with high field strength such as Mg2+.

Study on novel high refractive index La2O3-Lu2O3-TiO2 glasses prepared by aerodynamic levitation method

A new La2O3-Lu2O3-TiO2 glass with high refractive index was successfully prepared by containerless processing method. Although this glass without network formers performs low glass forming ability, aerodynamic levitation has been introduced to obtain the bulk glass spheres with a diameter of ∼3.5 mm. The glass shows good mechanical properties with the Vickers hardness of 8.26 GPa and fracture toughness of 1.09 MPa·m1/2. The density is up to 5.51 g/cm3, which is favorable to obtain high refractive index. The glass performs good thermal stability with the glass transition temperature as high as 812 °C. nd value of refractive index is as high as 2.1202. And Abbe number is 28.2. This indicates that the glass shows excellent optical properties, which can satisfy commercial requirements. Moreover, new glass also overcomes the shortage of deep color of conventional high refractive heavy metal oxide glasses. The transmittance of the glass is near to 75% in the visible and near infrared range.

Synthesis of amorphous La4Ti9O24 microspheres with high-refractive index via containerless flame-spraying method

The amorphous La4Ti9O24 microspheres were fabricated by a containerless flame-spraying method. The morphologies, structures, components and thermal stabilities of the microspheres were investigated by scanning electron microscope, optical microscope, X-ray powder diffraction apparatus, energy dispersive x-ray diffraction analysis and differential scanning calorimetry measurement. The as-prepared microspheres were transparent, and possess high reflective index. We further studied the optical application of these glass microspheres with high-reflective-index. The coating of La4Ti9O24 glass microspheres greatly increased the reflection of glass slide as substrate in the wide wavelength range (300–2000nm), which is very useful for some special surfaces that require illumination from reflection of light rays, such as protective reflective helmet or clothes, road side signs, etc. In addition, it can be used as heat reflective layer, which solves the urban heat island effect.

Large-sized La$lt;inf$gt;2$lt;/inf$gt;O$lt;inf$gt;3$lt;/inf$gt;-TiO$lt;inf$gt;2$lt;/inf$gt;-SiO$lt;inf$gt;2$lt;/inf$gt; Amorphous Oxide Fabricated by Hot Press Sintering

La2O3-TiO2 amorphous oxide has prospective applications because of its remarkable optical properties. However, due to its poor glass-forming abilities, it is difficult to prepare this material in a traditional way. The containerless solidification method can overcome this shortcoming, but the formed material size is generally restricted to be less than 10 mm. In order to obtain large-sized La2O3-TiO2 amorphous oxide, a small amount of SiO2 was added to the La2O3-TiO2 oxide system to form the amorphous oxide powders by aerodynamic levitation furnace. Subsequently, the high-density La2O3-TiO2-SiO2 materials were fabricated by vacuum hot press sintering. Compositions and microstructure properties were systematically studied by XRD and SEM. The results showed that SiO2 could improve the glass-forming ability of La2O3-TiO2. The raw powders made by aerodynamic levitation furnace were completely non-crystal, while the sintered samples had weak crystallization, which affected fully densification of sintered samples. There was a small amount of porosity in the high-density product made by vacuum hot press sintering. In addition, sintering densification mechanism of the La2O3-TiO2-SiO2 amorphous powders was analyzed. Finally, the optical property of hot pressed La2O3-TiO2-SiO2 material was investigated. It is found that La2O3-TiO2-SiO2 material still kepts high refractive index of above 2.2 in the visible light region. Small amount addition of SiO2 species improves the glass-forming abilities, yet decreases the refractive index slightly.