System Na2O Research Articles

Designing high-performance ion-exchangeable glasses with multi-objective optimization and machine learning

Ion exchange typically involves replacing smaller ions with larger ions below the glass transition temperature. This study introduces an innovative computational approach for the inverse design of ion-exchangeable glasses. It aims to simultaneously achieve high depth of layer (DOL) and surface compressive stress (CS), a task complicated by the inherent trade-offs between these properties. Traditional ion exchange experimental methods are not only time-consuming and expensive, but they also involve complex practical difficulties. Addressing these challenges, this paper introduces a novel computational approach that synergistically combines a multi-objective genetic algorithm with machine learning models. The approach involves training models on a diverse set of glass compositions to predict DOL and CS, which then guide an evolutionary algorithm to optimize these properties concurrently. Physics-informed parameters further refine the search, enabling a flexible design framework in glass manufacturing. Comprehensive experimentation and subsequent analysis affirm the proposed method's capacity to efficiently and effectively traverse the intricate design landscape of glass materials. The findings elucidated the influence of distinct compositional and process parameters on DOL and CS, facilitating the manual design process. Additionally, the study identified sixteen glass composition candidates within the SiO2–B2O3–Al2O3–MgO–Na2O system, exhibiting remarkable properties. Specifically, some compositions achieved a DOL of up to 95 μm with a corresponding CS of 890 MPa, while others attained a CS of up to 1654 MPa with a DOL of 14.72 μm.

A sol-gel templating route for the synthesis of hierarchical porous calcium phosphate glasses containing zinc

Hierarchical porous phosphate-based glasses (PPG) have great potential in biomedicine. Micropores (pore size <2 nm) increase the surface area, mesopores (pore size 2–50 nm) facilitate the absorption and diffusion of therapeutic ions and molecules making them ideal controlled delivery systems, while macropores (pore size >50 nm) facilitate the movement and diffusion of cells and fluids. In addition, the bioresorbability of PPG allows for their complete solubility in body fluid, alongside simultaneous formation of new tissue. Making PPG via the traditional melt-quenching (MQ) synthesis method used for phosphate-based glasses (PG), is not straightforward. Hence, we present here a route for preparing such glasses using a combination of sol-gel (SG) and templating methods. Hierarchical PPG in the P2O5–CaO–Na2O system with the addition of 1, 3 and 5 mol % of Zn2+ were prepared with pore dimensions ranging from the micro-to the macro scales using Pluronic 123 (P123) as a surfactant. The presence of micropores (0.30–0.46 nm), mesopores (1.75–9.35nm) and macropores (163–207 nm) was assessed via synchrotron-based Small-Angle X-ray Scattering (SAXS), with the presence of the latter two confirmed by Scanning Electron Microscopy (SEM). Structural characterisation performed using 31P solid state magic angle spinning nuclear magnetic resonance (MAS NMR) and Fourier Transform Infrared (FTIR) spectroscopies shows the presence of Q2, Q1 and Q0 phosphate species with a predominance of Q1 species in all compositions. Dissolution studies in deionised (DI) water confirm that controlled release of phosphates, Ca2+, Na+ and Zn2+ is achieved over a period of 7 days. In particular, the release of Zn2+ is proportional to its loading, making its delivery particularly easy to control.

Evaluating Phase Relations in Molten Oxides for Electrochemical Operating Windows for Selective Metal Reduction

AbstractMolten oxide electrolysis is a promising pathway to decarbonize primary metal production. The oxide electrolyte is less hazardous and eco‐toxic than halides (molten salt electrolysis) and, with the use of renewably generated electricity and an inert anode, oxygen is produced as a by‐product instead of CO2. Building fundamental understanding of electrolytic operating windows requires starting with simple chemistries. Here we investigate a simplified binary oxide system as an electrolyte for titanium oxide reduction to metal. The TiO2−Na2O binary system forms a eutectic, reducing the liquidus temperature over a wide composition range. FactSage 8.1 predictions suggested Ti reduction would become favorable over Na reduction for compositions greater than 0.49 mole fraction TiO2. The prediction was validated by the detection of metallic Ti after electrolysis experiments. However, the reduction efficiency was too low (0.24±0.08 % at −0.1 V vs Ti reference electrode) for the TiO2−Na2O system to be a viable industrial electrolyte for Ti production. Scoping for other binary oxide systems was performed for electrolytic production of two critical metals, tantalum and neodymium. Based on TiO2−Na2O system's predicted behavior, candidate binary oxide systems were identified that contained congruently melting line compounds flanked by eutectic reactions from the ACerS‐NIST Phase Equilibria diagrams database.

Synthesis and investigation of the V2O5 effect on the properties of Na2O–NiO-(1-x)P2O5–xV2O5 (0≤x≤0.6) system

This study reports on the properties of glasses and glass-ceramics isolated in a novel ternary system Na2O–NiO-(1-x)P2O5–xV2O5 with varying concentrations of V2O5 (x = 0, 0.2, 0.4, and 0.6 mol%). The materials were prepared by melting the mixture of reagents with stoichiometric proportions. Their amorphous and crystalline nature was confirmed via the XRD analysis. The vitreous feature and thermal parameters of the glasses were explored using differential scanning calorimetry. The density values have shown an increase and a slight decrease in the molar volume with the increase in the V2O5 content. The elemental composition of the glass and glass-ceramics was studied using energy-dispersive X-ray spectroscopy. In addition, the study examined the influence of the composition on the structure of the materials using both IR and Raman spectroscopies. XRD analysis of annealed samples revealed the presence of different crystalline phases depending on the V2O5 content. The EPR results were influenced by the variation of concentration of V2O5 and indicated the presence of V4+ ions in octahedral sites with tetragonal compression. The analysis of the magnetization according to the magnetic field at different temperatures showed a ferromagnetic behavior at low temperatures and a paramagnetic one at higher temperatures for all glasses. Magnetic susceptibility data reveal a Curie-Weiss behavior and the predominance of antiferromagnetic interactions. The dielectric studies were conducted as a function of temperature and frequencies to evaluate the composition effect on the dielectric constant, dielectric loss, and ionic conductivity. Electrical features were also examined using impedance spectroscopy.

Glass with a low-melting temperature belonging to the P2O5–CaO–Na2O system, applied as a coating on technical ceramics (alumina, zirconia) and traditional ceramics (porcelain stoneware)

This article investigates the development and potential applications of low-melting point lead-free glasses. Their importance is due to strong market demands to comply with the strict international regulations against the use of lead. In this work, a preliminary study of the existing interactions of a low-melting-temperature glass belonging to the P2O5–CaO–Na2O system when it is deposited on different ceramic substrates, both traditional (porcelain stoneware) and technical (alumina and zirconia), has been carried out. The ionic diffusion through the studied interfaces, the phases present, the composition of the glassy phase and the surface morphology of the coating have been studied by Field Emission Scanning Electron Microscopy (FESEM), with coupled EDX microanalysis. The chemical resistance of the different glassy coatings obtained is also evaluated. The results showed that these new lead-free low-melting-temperature glassy coatings are chemically and mechanically compatible, and promising candidates for applications and markets in a broad range of fields.

MODIFICATION OF LANTHANUM OXIDE La&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; ON THE STRUCTURE OF SUPRASTRUCTURAL UNITS IN ALKALI BORATS

It shows a significant change in structurally sensitive properties in the experiment of modifying a melt (or glass) of the B2O3–Na2O system with lanthanum oxide La2O3 with the destruction of superstructural units when lanthanum atoms hit, since small additions of rare earth metal oxides lead to a significant change in the properties of alkali borate melts. Molecular models of some of the superstructural units, the structure and properties of which were calculated by semi-empirical quantum chemical methods with MNDO and PM7 parameters: as a result of the optimization procedure, both methods lead to models that are qualitatively close, but differ in bond lengths, and practically the same value of heat of formation. The superstructural unit of the considered type is preserved, while its characteristics change: the volume occupied by it increases, the newly formed bond is less strong and its ionic degree is greater.

Effect of gamma ray irradiation on optical and luminescence properties of CeO2 doped bismuth glass

High lead oxide based Radiation Shielding Window (RSW) glass is highly toxic in nature and thus health hazardous. Therefore, a new way to design environmental friendly non-toxic lead-free RSW glass for nuclear application is very much required. In this work, a lead-free non-toxic glass based on multi-component Bi2O3–BaO–B2O3–ZnO–As2O3–MgO–Na2O system has been studied with different concentrations of cerium oxide (CeO2) as doping agent for enhancing radiation shielding effect. The optical properties of cerium doped bismuth based lead-free radiation shielding glass after exposure to gamma radiation up to 105 rad have been studied. The densities of glass varied from 4.59 to 5.05 g/cc on varying concentrations of bismuth oxide and boron trioxide in glass system. The transmission properties in visible regions from 400 to 1000 nm are investigated through UV–visible spectrometer after exposure to gamma radiation on developed glass using 60Co Gamma Chamber GC5000. The structure of glass as characterized by Raman spectroscopy, XRD, Photoluminescence (PL), FESEM with EDAX, refractive index measurement and dilatometry test has been correlated with its properties. The developed bismuth glass could find its application as lead-free RSW glass in nuclear reactors as an alternative to high lead containing glass.

The usability of the Judd-Ofelt theory for luminescent thermometry using Eu3+-doped phosphate glass

The Judd-Ofelt theory, which is the most thorough and insightful method to determine theoretically the luminescent properties of the trivalent rare earth dopants, is here tested on Eu3+-doped glasses in the P2O5 – SrO – CaO – Na2O system to assess their usefulness as luminescent thermometers. It is demonstrated that the thermometric sensitivity (change of the emission lines ratio in response to change in temperature) can be estimated using the Judd-Ofelt theory and aligns well with the experimentally obtained values. It is shown here that the addition of B2O3 or SiO2 in a phosphate network increases the absolute sensitivity due to an increase in the phosphate network connectivity while having no significant impact on the site of Eu3+ ions. The applicability of the Judd-Ofelt theory for predicting the thermometric parameters of a glass luminescent material, without the time-consuming measurement of the glasses spectroscopic properties as a function of temperature, is clearly demonstrated and allows for further development of novel efficient luminescent thermal sensors with high sensitivity.

Design, synthesis and structural properties of borate glasses: Towards an alkali-free bioactive glass

Glasses in the system (14-x) Na2O-(54+x) B2O3–22CaO-8MgO-2P2O5 with 0 ≤ x ≤ 14 mol%, have been prepared by the classic method, fast quenching of high-temperature melts. Multiples techniques were used to investigate their physical and structural properties such as X-ray diffraction, Density measurements, Differential scanning calorimetry, Infrared spectroscopy, Raman spectroscopy, and Isothermal heat treatment. The results found by Raman and Infrared spectroscopy show that the addition of boron oxide in different proportion and the progressive reduction of sodium oxide affect clearly the glass structure, wherewith the total elimination of Na2O the glass network exhibit the formation of an interconnected large cluster (pentaborate) at the detriment of the isolated unit containing non-bridging oxygen, thus promoting groups with four coordinated boron. The physical parameters and thermal analysis confirm the structural results found revealing an increase in the oxygen packing density and glass transition temperature from 510 °C to 640 °C indicating compactly packed structure and a reinforcement of the glass network. The isothermal treatment confirms the role of boron by maintaining the vitreous aspect until (800 °C) for the alkali-free glass, in addition to a much higher thermal stability. The bioactivity test was achieved by immersion glass samples in simulated body fluids solution (SBF) at 37 °C, these latter within a few days reveals the growth of the hydroxyapatite phase confirmed by X-ray diffraction, FT-IR, and scanning electron microscope. Also, the conversion process was proved with the increase in pH and the weight loss values as well as the consumption of Ca and P concentration in simulated body fluids solution. However, the kinetics of the reaction decreases with the substitution of Na2O with B2O3 in the glass system which is quite related to the creation of more interconnected bonds and less non-bridging oxygens. Thus the properties found of the alkali-free glass in correlation with the formation of hydroxyapatite layer indicate a potential glass for tissue engineering application.

Calculation and experimental determination of equilibrium composition of liquors in certain instances of the Na2O – К2O – Al2O3 – H2O System

Presently, one can definitely state a rising interest to potassium-bearing aluminium ores, which is due to a gradual depletion of conventional raw materials and the fact that the ores that are mined today are leaner and have a more complex composition. At the same time, soda-potassium products, potassium fertilizers, aluminium hydroxide, alumina and alumina materials are in high demand and sell at high prices. Today, the focus is on new deposits of urtite rock and nepheline ores, as well as those of ultrapotassium rischorrite and synnyrite rock. That&rsquo;s why it is very important to have a basic understanding of the nature and properties of the technically important system Na2O &ndash; К2O &ndash; Al2O3 &ndash; H2O, which defines the performance of the key processes involved, as well as the output and quality of the final product. In this regard, studying phase equilibria in the above system, the information about which is lacking or inconsistent, can be pointed out as one of the current research priorities. Two methods were tested aimed at reducing the time necessary to reach equilibrium in the Na2O &ndash; K2O &ndash; Al2O3 &ndash; H2O system. One involves hydrolytic decomposition of aluminate liquors with aluminium hydroxide used as seed; the other involves a mathematical description of the curves characterizing the kinetics of gibbsite solubility in alkaline liquors with a given mole fraction of K2O. Similar laboratory equipment and materials were used in the experimental study regardless of the way equilibrium was reached and identified. Through experiments, it was established that the process of approaching equilibrium in predominantly potassium aluminate liquors has complex kinetics and mechanics impeding rapid identification of equilibrium composition of liquors. With regard to the technique that involves gibbsite dissolution in weak sodium-potassium liquors, the authors demonstrate how asymptotic approximation functions can be effectively used to determine maximum solubility of aluminium oxide. The results of experiments aimed at defining the equilibrium compositions of liquors at 60 oC in certain instances of the Na2O &ndash; К2O &ndash; Al2O3 &ndash; H2O system have a good and satisfactory correlation with the modelling data based on the additivity principle, which suggests that the modelling technique can effectively be applied to other temperatures and instances of the 4-component system in view. This research was funded by the Russian Science Foundation under the Agreement&nbsp;No. 18-19-00577-П dated April 28, 2021 on granting funds for basic scientific&nbsp;research and exploratory research.

Improving the Quenching of the Undercarriage Space due to the Adhesive Properties of Gel-Forming Compositions

The issue of increasing the technological and technical capabilities of firefighting undercarriage space at subway stations due to more efficient, due to adhesion to the burning surfaces of gel-forming compositions is considered. It is proposed to use a special cart to deliver the gel-forming system Na2O·2,95SiO2 – CaCl2 to hard-to-reach locations of electromechanical and other equipment of electric trains. The analysis of these experiments is carried out by comparing the time and mass of spent gel-forming compositions, water, fire-extinguishing powder when extinguishing model hearths close to the real undercarriage space. It is determined that due to the adhesion of the gel to the surface of the combustible substance, it is possible to reduce the loss of extinguishing agent in comparison with water or extinguishing powder.

Phase Equilibrium of the V2O5–Na2O System

Knowledge of the equilibrium phase relationship in the V2O5–Na2O system is critical and essential for the sodium salts roasting process of slag-bearing vanadium, and those fundamental studies can be used to accelerate industrial optimization and update the process. Therefore, phase equilibrium and quenching and thermal analysis experiments on the V2O5–Na2O binary system were carried out in the present work under pO2 of 10−3.5 atm. The V2O5–Na2O system has 7 primary phase fields including two simple oxides (V2O5 and Na2O), and 5 binary compounds (Na2V12O31, Na10V24O65, NaVO3, Na4V2O7, and Na3VO4). The existence of Na2V12O31 and Na10V24O65 was experimentally confirmed and then characterized by EPMA, no extensive compounds or solid solutions were detected in the present study. The liquidus lines were experimentally determined in most of the primary phase fields in the temperature range from 500 °C to 800 °C. The temperatures and components of some invariant reactions, including Liq → V2O5 + Na2V12O31 (640 °C, 53 mol pct Na2O), Liq → Na10V24O65 + NaVO3 (504 °C, 40.2 mol pct Na2O), Liq → NaVO3 + Na4V2O7 (540 °C, 59.0 mol pct Na2O), and a new peritectic reaction at 570 °C with 32 mol pct Na2O were rechecked, and Liq + Na2V12O31 → Na10V24O65 was also reconstructed. The large amount of new phase equilibrium data proposed in this work will serve as reliable input for future thermodynamic reassessments of the V2O5–Na2O system within the CALPHAD framework to extensively improve the current V2O5-based thermodynamic databases.Graphical Abstract

Thermodynamic Modelling of Ion Equilibria in the Na2O – Al2O3 – H2O System with Gibbsite

The structure and ionic composition of aluminate solutions are the key problems in the theory of alkali-based alumina production. Good understanding of these problems determine how adequately the processes will be evaluated that take place at different stages of aluminium material processing and if modern digital twins of processing plants can be enhanced with flexible thermodynamic and kinetic models. Most researchers recognize two forms of complex alumi nium anions for the process critical region of the Na2O &ndash; Al2O3&ndash; H2O and K2O &ndash; Al2O3 &ndash; H2O systems. They exist in the form of hydrated monomers and dimers of meta-aluminate ion. Based on the analysis of phase equilibria in the Na2O &ndash; Al2O3 &ndash; H2O system, it was established that the degree of nonlinearity of solubility isotherms can serve as an indicator of a more complex composition of aluminate solutions with dimers of tetrahydroxo complexes of meta-aluminate ions, and helps calculate the ionic composition for an isothermal model with two ionic forms of aluminium. It is shown that, with the participation of dimers, the region of the corresponding equilibria can be determined by building solubility isotherms in the form of the following function: [Al2O3] = f ([Na2O] &ndash; [Al2O3]). It helps narrow the range of model representation of coexistence between monomers, dimers and dehydrated meta-aluminate ions in the system Na2O &ndash; Al2O3 &ndash; H2O. The modelling results show that, with the participation of dimers of tetrahydroxo complexes of meta-aluminate ions, the region of phase equilibria tends to expand significantly as the temperature rises and, with the participation of dimers, the equilibrium maximum tends to shift into the region of low-alkaline solutions. Thus, the equilibrium isotherms in the Na2O &ndash; Al2O3 &ndash; H2O system at the temperatures of 30, 60, and 95oC include phase equilibria involving one, two or three ionic forms of aluminium, the fraction and the region of which are determined by the concentration of alkaline component and the temperature.This research was funded by the Russian Science Foundation under Agreement&nbsp;No. 18-19-00577-П dated April 28, 2021 on the Provision of a Grant&nbsp;for Conducting Fundamental and Exploratory Research Studies.

Spectroscopic studies of preparation conditions role on the shielding properties of MoO3-doped Na2O–ZnO–P2O5

Glassy samples from the undoped ternary system Na2O–ZnO–P2O5 in combination with other samples from the same system doped with variable amounts of MoO3 (0.25, 0.5, or 1 gm/batch) were successfully melted under ordinary, oxidizing, or reducing conditions followed by annealing. Fourier transform infrared spectrophotometric measurements in combination with optical absorption spectra were recorded before and after doping with variable concentrations of MoO3 in multiple melting media both as prepared or after being subjected to (8 Mrad) gamma irradiation dose. The studied spectral properties of the glasses were correlated with variations with the existing valence state of the Mo ions and the effects of gamma irradiation on the optical spectra and IR vibrational bands together with the role of the condition of melting the batches. The optical spectra of the glasses reveal pronounced UV and visible bands due to trace iron (Fe3+) ions as impurities or the sharing of the low valence states of the added molybdenum ions. The FTIR peaks show condensed spectra of phosphate groups (Q2, Q3), and the effects of dopant are limited because of low percent. Gamma irradiation causes distinct variations in the undoped spectra, but the MoO3-doped glasses show some shielding behavior.

Excellent 2.8 μm fluorescence properties of Dy3+ ions by optimizing the structure of tellurite glasses

Optimizing the luminescence performance of Dy3+ ions by regulating the composition and structure of glass is of significant importance for the further development of mid-infrared (MIR) lasers. In this study, a TeO2–Na2O system was selected as the glass matrix owing to its wide glass-forming range for Dy3+ doping, while B2O3, MgO, and ZnO were selected as modifiers to the binary system to improve the thermal and optical properties. MgO was found to improve the crystallization resistance of the tellurite glass matrix, as revealed by differential scanning calorimetry. Raman and x-ray photoelectron spectroscopy results showed that the structure of the matrices became more flexible with the addition of ZnO. More non-bridging oxygen was released, which aids the enhanced 2.8 μm emission of Dy3+ ions. Therefore, these tellurite glasses are suitable laser gain mediums for Dy3+ luminescence, and the structure can be adjusted according to the requirements of specific practical applications in the MIR band.

Comparative study of the crystallization behavior within the Na2O–Y2O3–ZrO2–SiO2 system during heating and cooling

Glasses from the system Na2O–Y2O3–SiO2 with different concentrations of ZrO2 were studied concerning phase formation and crystallization behavior.

Coupled experimental phase diagram study and thermodynamic optimization of the Na2O–B2O3–Fe2O3 system in air

Coupled key phase diagram experiment and thermodynamic optimization of the Na2O–B2O3–Fe2O3 system were carried out. Liquidus in the Na2O–B2O3–Fe2O3 system in air was experimentally determined at 1173, 1273, 1373, and 1473 K using a classical quenching method followed by Electron Probe Micro-Analyzer (EPMA) and X-Ray Diffraction (XRD) phase analysis. Based on the new phase diagram data and available literature data, the thermodynamic optimizations of binary B2O3–Fe2O3 system and ternary Na2O–B2O3–Fe2O3 (Na2O < 50 mol%) system in air were carried out. All the reliable experimental phase diagram data were reproduced within an experimental error limit. Thermodynamic properties and phase diagrams of the ternary Na2O–B2O3–Fe2O3 (Na2O < 50 mol %) in air were predicted from the thermodynamic models with optimized model parameters.

Alkali Metal (Li, Na, and K) Orthocarbonates: Stabilization of sp3-Bonded Carbon at Pressures above 20 GPa

In the present work, based on the density functional theory and crystal structure prediction algorithms, we found novel structures of alkali metal orthocarbonates Li4CO4-C2/c, Na4CO4-C2/c, and K4CO4-P21/c. The pressure of thermodynamic stabilization of the obtained orthocarbonates with respect to decomposition into the corresponding carbonate and oxide ranges from 21 GPa (for K4CO4) to 25 GPa (for Li4CO4). All obtained structures contain isolated groups of [CO4]tetrahedra. The structures of lithium and sodium orthocarbonates were found to be isotypic. As well as alkaline earth orthocarbonates, orthocarbonates of alkali metals are structurally similar to orthosilicates of the same metal. Na4CO4-C2/c was found to be dynamically stable at ambient pressure, while all other structures are destabilized on decompression. In addition, the P–T phase diagrams of lithium, sodium, and potassium oxides have been calculated for the first time. All oxides have a high-pressure phase transition from the Fm3̅m (anti-fluorite) structure to the Pnma (anti-cotunnite) structure at 34 GPa for Li2O, at 10 GPa for Na2O, and at 5 GPa for K2O at low temperatures. In the Na2O and K2O systems, high-temperature phase transition to the P6̅2m (barringerite) structure was revealed at temperatures above 1300 and 650 K, respectively.

Mixed anionic double sodium-cobalt(II) diorthodiphosphate: structure and growing of single-crystals

The solubility of cobalt oxide was determined in the melts of the system Na2O–P2O5–CoO–NaF in a wide range of molar ratios Na2O:P2O5 (0.5–2.0) and temperatures of 800–9000C at the sodium fluoride content of 10 wt.% and 20 wt.%. The region of existence and optimal conditions for growing monocrystals of complex phosphate Na4Со3(PO4)2P2O7 in the melts of the system Na2O–P2O5–CoO–NaF was found out. The synthesized compound was investigated using a number of physicochemical methods (IR spectroscopy, diffuse reflection spectroscopy, X-ray phase analysis, X-ray structure analysis and differential thermal analysis). The complete chemical analysis of the synthesized compound was performed and the melting temperature was determined 7650С, without decomposition). The X-ray diffraction analysis of Na4Со3(PO4)2P2O7 single crystals was carried out and the unit lattice parameters were determined. Phosphate crystals belong to the rhombic crystal system, sp. gr. Pna21; crystal lattice parameters are as follows: a=18.021(1) Å, b=10.389(2) Å, c=6.532(2) Å, V=1222.47(1) Å3, Z=4, сcalc=3.47 g cm–3. The following specific features of the structure of complex phosphate Na4Со3(PO4)2P2O7 have been established: the presence of conduction channels for the sodium ion along the oy axis and the presence of differently coordinated Na and Co polyhedra with an uncharacteristic coordination number. The optimal conditions for the growth of complex phosphate single crystals with a high weight yield were selected. The use of the synthesized compound Na4Со3(PO4)2P2O7 as a functional material with ion conductivity was suggested.

Raw glass-ceramics glazes from SiO2–Al2O3–CaO–MgO–Na2O–K2O system modified by ZrO2 addition – Changes of structure, microstructure and surface properties

In this paper, raw glazes from the SiO2–Al2O3–CaO–MgO–K2O–Na2O system were examined. Zirconium oxide, in five different amounts – 1.5, 3, 6, 12 and 24 wt%, was added to the chosen system and heat treated at 1230 °C, where they were kept for an hour. The addition of zirconium oxide, especially in greater amounts, caused the crystalline phase of zirconium silicate and intact ZrO2 grains to appear. The amounts of these crystalline phases indicate that zirconium cations are present in the amorphous phase. Analysis of structural measurements showed that zirconium ions (Zr4+) have a depolymerizing effect on the glassy matrix of the glazes; however, it does not change subnets of an aluminum-silicon subnetwork. This is a new perspective on the matter, because it confirms that the addition of zirconium oxide causes those ions to be present not only in crystalline phases, but also some Zr4+ cations are located in the aluminosilicate subnetwork (Si–O–Si(Al)), in interstitial spaces, and it interacts only with silicon-oxygen bonds. Measurements of the color in the CIE L*a*b* system of the obtained glazes confirmed that the addition of zirconium oxide results in glaze with significantly higher whiteness (L* parameter increases) and a more monochromatic color (a* and b* parameters tend toward zero). The results of the surface smoothness were also presented, which clearly confirm that the higher content of zirconium crystalline phases results in obtaining a surface with higher roughness.