Glass Addition Research Articles

Effects of Bi2O3 and Li2O B2O3Bi2O3SiO2 glass on electromagnetic properties of NiCuZn/BaTiO3 composite material at low sintering temperature

Abstract Bi2O3 and Li2O B2O3 Bi2O3 SiO2 (LBBS) glass were introduced into Ni0.15Cu0.24Zn0.61Fe2O4 BaTiO3 ((NCZF-BTO) composite materials as sintering aids and sintered at 920 °C. Effects of Bi2O3 and LBBS glass on phases, microstructures, magnetic and dielectric properties of these composites were comparatively studied. In contrast to undoped composites, the addition of Bi2O3 or LBBS glass to samples enhances performance. Hence, when Bi2O3 content reached 1.5 wt%, saturation magnetization (4πMs) increased from 3825.4 to 4912.5 Gs, static permeability (μ0) increased from 53.2 to 197, and dielectric constant (e′) increased from 18.3 to 23.4. When LBBS glass content reached 1.5 wt%, 4πMs increased to 4145.6 Gs, μ0 increased to 79.3, e′ increased to 25.4. However, both coercivity (Hc) and dielectric loss (tan δ) were reduced. In short, Bi2O3 promoted magnetic properties, whereas LBBS glass promotes dielectric properties more effectively.

Effects of Bi2O3–ZnO–B2O3–SiO2 glass addition on the sintering and microwave dielectric properties of ZnZrNb2O8 ceramics for LTCC applications

A novel low-temperature sinterable microwave dielectric ceramic was successfully developed by adding low-melting-point Bi2O3–ZnO–B2O3–SiO2 (BBSZ) glass to ZnZrNb2O8 (ZZN) ceramic. The influence of BBSZ glass on the densification behavior and microwave dielectric properties of ZZN ceramic was systematically investigated by means of an X-ray diffractometer, a scanning electron microscope and a network analyzer. By adding an appropriate amount of BBSZ glass into ZZN ceramic, the sintering temperature was lowered to 950 °C, indicating that BBSZ glass was an effective firing agent for ZZN ceramic. Furthermore, favorable microwave dielectric properties of ɛr = 32.5, Q×f = 38,400 GHz and τf = − 51 ppm/°C were yielded in the ZZN sample with 6 wt% BBSZ glass addition, simultaneously maintaining uniform and compact microstructure. The chemical compatibility between the present composite and Ag electrode was also investigated for commercial applications.

Research on strength properties of geopolymer based on tungsten mine waste and recycled ground glass

Introduction: Geopolymers are the modern inorganic materials obtained as a result of chemical reaction under strongly alkaline conditions. The main advantages of these materials are: high strength parameters, fire resistance, frost resistance and resistance to aggressive environment. Because of lower CO2 emission during production process, they are also considered as environmentally friendly materials in comparison to ordinary Portland cement (OPC) systems. Objectives: The aim of the investigation was to define the impact of recycled ground glass addition on mechanical properties of geopolymeric binder made from tungsten mine waste. Methods: The strength parameters of geopolymeric samples were determined on the basis of three-point flexural test and uniaxial compression test. Results: The geopolymer samples that contain 20%, 40% and 80% of recycled ground glass present similar flexural strength. The compressive strength of glass-based geopolymers increases with growing content of recycled ground glass. Conclusions: In terms of flexural strength, the most favourable composition was the mixture composed of 60% recycled ground glass and 40% tungsten mine waste. In terms of compressive strength, the most favourable composition was the mixture composed of 80% recycled ground glass and 20% tungsten mine waste.

Performance evaluation of sustainable high strength mortars incorporating high volume waste glass as binder

This study investigates the performance of sustainable high strength mortars incorporating recycled waste glass as a supplementary cementitious material (SCM) to replace cement from low (10%) to high (60%) replacement ratios, while mortars with conventional mix design are used as reference. The addition of the recycled waste glass significantly improves the slump-flow of fresh mortars in the presence of superplasticizer (SP). The increase of the recycled waste glass dosage contributes to the longer initial and final setting time compared to the plain cement sample. The high volume recycled waste glass containing sample shows an obvious delay of hydration compared with others incorporating the same amount of SP. The high strength series samples containing various contents of recycled waste glass show similar total gel porosity, but a significant increase of gel porosity was observed in the normal strength series samples containing recycled waste glass. From the SEM images, it can be identified that high dosage recycled waste glass-containing high strength mortars show a denser microstructure compared to the plain sample. The higher mesopore volume introduces higher drying shrinkage in sustainable mortars. The mechanical performance tests show that sustainable high strength mortars containing 60% recycled waste glass can achieve a satisfactory strength (99 MPa) compared to the plain cement sample (115 MPa).

Effects of powdered glass as an admixture in cement concrete block

This paper investigated the effects of glass usage in finely divided form on the properties of cement concrete. The powdered glass was used as admixture, replacing cement in the concrete production process. The sourced glass were washed and dried for some days. The dried glass was then crushed into smaller pieces before grinding to finely divided form. Replacement of cement with powdered glass was done at 0-10% with 2% increment by weight of cement. Using a design mix of 1:2:4, with a constant water cement ratio of 0.6, the workability of fresh specimens were determined using the slump height procedure. The specimens were then poured in 150x150x150mm steel moulds and left for 24 hours. The hardened concrete specimens were cured by complete immersion in water for 7, 14, 21 and 28 days. The result showed that workability increases with increase in admixture content. It further revealed that the compressive strength increases with admixture addition to about 4% powdered glass addition. The compressive strength at 6% addition of powdered glass was also higher than that of the conventional concrete. Thus replacement can be done to about 6% addition of powdered glass by weight of cement. The models developed from the study corroborated well with experimental values as high coefficient of determination values were obtained. The models can thus, be used to predict the compressive strength of powdered glass-cement concrete. Keywords: Admixture, Cement Concrete, Compressive Strength, Slump, Powdered Glass

The influence of lithium compounds on alkali – silica reaction in calcium aluminate cement mortars subjected to the deicing salts attack

Paper presents the results of research on the effect of the lithium nitrate and carbonate addition on the alkali – silica reaction in calcium aluminate cement mortars, subjected to the a deicing salts attack. Mortars with the addition of quartz glass as the reactive aggregate were immersed in 4.5 molar sodium acetate, chloride and hydroxide solutions according to the modified ASTM C1260 method. In all cases, the mortars exhibited expansion, the highest for samples immersed in the acetate solution, and the lowest in the hydroxide solution. The addition of 1% of lithium carbonate in respect to the cement mass slightly reduces the expansion of mortars immersed in sodium acetate and hydroxide solutions. The addition of 1.86% and 3.73% of lithium nitrate increases the expansion of mortars immersed in both solutions. The addition of 1.86% lithium nitrate reduces the expansion of the mortar stored in sodium hydroxide solution, while 3.73% of this addition increases the expansion of this mortar. Changes in the microstructure were also presented.

Effect of addition of bioactive glass to resin modified glass ionomer cement on enamel demineralization under orthodontic brackets.

BackgroundEnamel demineralization and white spot lesions around orthodontic brackets is a common problem associated with fixed orthodontic treatment. Glass ionomer cements (GICs) are commonly used for bracket bonding and recently, bioactive glass (BAG) was added to GICs to enhance deposition of calcium phosphate in adjacent dental structure. This study sought to assess the effect of addition of BAG particles to resin modified GIC (RMGIC) on enamel demineralization under orthodontic brackets.Material and MethodsIn this in vitro, experimental study, 60 sound human premolars were immersed in distilled water at 6°C. The teeth were randomly divided into three groups. Using a sticker, a window measuring 7x7 mm was created on the buccal surface. The remaining surfaces were coated with nail varnish twice with a 3-hour interval. After 24 hours, the stickers were removed. Brackets were bonded to tooth surfaces using Transbond XT (control), Fuji II LC RMGIC and Fuji II LC containing 30% BAG particles. To induce acid attacks, the teeth were immersed in demineralizing solution for 6 hours. For pH cycling, the teeth were then immersed in remineralizing solution for 18 hours. This process was repeated for 21 days. Next, the teeth were longitudinally sectioned into two halves and the depth of demineralization was measured from the deepest point to the surface under a polarized light microscope. Data were analyzed using one-way ANOVA, and pairwise comparisons were carried out using Tukey’s test.ResultsThe mean depth of demineralization was 73.8±22.29, 118.08±29.42 and 182.98±20.69 µm in the BAG, RMGIC and Transbond XT groups, respectively. One-way ANOVA showed significant differences in terms of depth of demineralization among the three groups (P=0.0001). Tukey’s test revealed significant differences in depth of demineralization.ConclusionsAddition of BAG to RMGIC can significantly decrease the depth of enamel demineralization under orthodontic brackets in vitro. Key words:Remineralization, demineralization, orthodontic brackets, bioactive glass, resin modified glass ionomer cement.

STRONG POROUS GLASS-CERAMICS FROM ALKALI ACTIVATION AND SINTER-CRYSTALLIZATION OF VITRIFIED MSWI BOTTOM ASH

Vitrification of municipal solid waste incineration (MSWI) bottom ash is an effective method to produce a chemically stable glass, with metal recovery. In order to justify the high costs of this process, the vitrified residue can then be upcycled into potential marketable products. In this study, vitrified bottom ash was successfully converted into strong and chemically stable porous glass-ceramics by the combination of alkali activation and sintering. After the activation of the glass in a NaOH solution of low molarity, foams were easily produced by intensive mechanical stirring, with the aid of a surfactant, and stabilized by gelation. The obtained open-celled material was further consolidated by a sintering treatment, at 800-900°C. The addition of recycled soda-lime glass allowed activation at low molarity and sintering at lower temperature, but it reduced the mechanical properties and the stabilization of heavy metals. On the other hand, the increase in molarity of the alkaline solution increased the porosity and also the strength of foams from vitrified bottom ash.

Performance of granular soils reinforced with obsidian (volcanic glass) additives in different proportions subjected to freeze-thaw

Performance of granular soils reinforced with obsidian (volcanic glass) additives in different proportions subjected to freeze-thaw

Lightweight Cement Mortars with Granulated Foam Glass and Waste Perlite Addition

This article presents the influence of granulated foam glass (GFG) on thermal insulation and mechanical properties of lightweight cement mortars. The mortars were additionally modified with addition of ground perlite dust. Ground expanded perlite waste was introduced into the cement matrix in the amounts of 10%, 20%, and 30% of cement mass. The results show that application of this waste increases the strength of the mortars as well as decreases their thermal conductivity coefficient. A series of mortars were prepared with introduction of granulated foam glass with mass per unit filler/cement ratio equal to 0.6, 0.9, and 1.2. The aggregate composition of GFG was combined from different monofractions in the range 0–2 mm so that it filled the mortar volume to the maximum. Additionally, mortars were made, in which 20% of 0–0.25 mm GFG volume was replaced with quartz sand with the same granulation. Each mortar series was modified with addition of ground perlite waste in the amount of 20% of cement mass. The results indicate an improvement of thermal insulation properties along with greater participation of perlite in the mortars. The increase of the thermal conductivity coefficient was observed in the mortars, where the GFG was replaced with quartz sand. Greater amount of GFG results in decrease of compressive strength, but it can be improved by replacing part of the lightweight filler with sand or by introducing the addition of ground expanded perlite to the matrix. This also results in lower water absorption of mortars. Research proved that in most cases, the addition of ground expanded perlite decreased the capillary sorption of mortars, as well as the water absorption coefficient by capillary action, with growing proportion of the lightweight filler.

Ballistic Behavior of New Alumina Composites Reinforced with Niobo-Phosphate Glass

This work aimed to produce and evaluate the ballistic behavior of niobo-phosphate glass-doped alumina composites. The niobo-phosphate glass (30% Nb2O5- 30% P2O5- 20% CaO - 20% CaF2, by mol) were added to the alumina in six different weight percentages. The composite with the highest densification, measured by the Archimedes assay, was used for the ballistic tests. X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray spectroscopy by dispersive energy (EDX) were also performed. The sintered samples were enveloped on two 1020 steel plates for the residual velocity test. The best results of densification were obtained for the niobo-phosphate glass addition of 4 wt%, which was not detected the AlPO4 phase formation. From the residual velocity test, it was observed a better energy absorption for the doped alumina, in relation to pure alumina. Therefore, it is indicated that the niobo-phosphate glass addition of 4 wt% worked properly as sintering aid for alumina, enhancing its properties and performance.

Elimination of the adverse effect of calcite slimes on the sulfidization flotation of malachite in the presence of water glass

In order to eliminate the adverse effects of calcite slimes on the sulfidization-xanthate flotation of malachite, water glass was used as a depressant for calcite slimes. Micro-flotation results indicated that the floatability of malachite was restored in mixed malachite and calcite by adding water glass. Addition of the water glass into the suspension of malachite with calcite slimes promoted dispersion of these minerals and increased the selective adsorption of sulfide ions onto the malachite. The dispersion effect was supported by results of sedimentation and electrokinetics. The zeta potentials significantly increased in the negative direction, primarily for calcite, which caused removal of its slimes from the malachite surface. Thus, floatability of this mineral with xanthate was restored since it allowed a more efficient sulfidization. The DLVO calculations performed, predict the observed behaviour of the sulfidization of malachite.

Effect of PbO–B2O3–BaO–SiO2 glass additive on dielectric properties of Ba0.5Sr0.5TiO3 ceramics for radio-frequency applications

In this work, the effects of PbO–B2O3–BaO–SiO2 (PBBS) glass addition (in increasing wt%) into Ba0.5Sr0.5TiO3 (BST0) ceramic on sintering, phase, and dielectric properties of BST0 are studied. The Ba0.5Sr0.5TiO3 (BST0) ceramic was synthesized by the conventional solid-state reaction method, and the PbO–B2O3–BaO–SiO2(PBBS) glass was formed by melting and quenching process. The PBBS glass with different weight percentages (3, 5, 8 and 10 wt%)is added to BST0 ceramic (BST3, BST5, BST8, and BST10, respectively) as a sintering aid to reduce the sintering temperature. Addition of glass helps in better sintering at lower temperatures with the presence of liquid phase at the respective sintering temperatures. The results of liquid phase-sintered ceramics are compared with the BST0 ceramic sintered at 1523 K. The BST10 with 10 wt% glass showed the lowest sintering temperature of 1148 K. Rietveld refinement analysis of BST0 ceramic confirmed the formation of single phase with cubic crystal structure. X-ray diffraction patterns of all liquid phase-sintered ceramics showed that the glass has minimal reaction with the BST0 ceramic and does not affect the crystal structure. Dielectric characterization was performed within the temperature range 20–450 K and frequency range 1 kHz to 1 MHz. It is revealed that the transition temperature shifted with different weight percentage of glass addition. All the compositions exhibit the paraelectric phase at room temperature. Dielectric properties were also measured in the microwave frequency range 8.5–11 GHz at room temperature. BST10 shows the stable and highest dielectric constant (average value of εr = 27) with lowest dielectric loss (tanδ = ∼0.121). Fourier transform infrared (FTIR) and Raman spectroscopy confirmed the formation of desired compositions by detecting molecular vibrations and chemical bonding. The synthesized ceramic is a low-cost candidate and can have potential uses in the radio-frequency applications.

Effect of 64S bioglass addition on sintering kinetic, flexural strength and osteoblast cell response of yttria‐partially stabilized zirconia ceramics

AbstractA quantity of 3 mol% yttria‐partially stabilized zirconia (Y‐TZP) with 10.5 and 19.9 vol% 64S bioglass compacts was sintered at different temperatures up to 1500°C. The influence of 64S glass addition on the sintering kinetic, flexural strength, and osteoblast cell response of Y‐TZP ceramics was investigated. The addition of 64S glass increased the initial sintering rate through the decrease in the activation energy and the increase on the order of diffusion with respect to those previously reported for Y‐TZP. Y‐TZP at 1500°C exhibited the highest flexural strength. Within Y‐TZP ceramics with 64S additions, a maximum flexural strength occurred for 10.5 vol% 64S at 1400°C, its flexural strength was able to approach that of Y‐TZP at 1500°C. The polished sintered surfaces became rougher as the 64S content increased. Cell viability experiments on the less nanoroughness Y‐TZP and Y‐TZP with 10.5 vol% 64S surfaces revealed their good biocompatibility; on the contrary, the high level of nanoroughness of Y‐TZP with 19.9 vol% 64S significantly reduced cell survival. However, the matrix mineralization was not adversely affected by the surface roughness; larger amounts of calcium phosphate phases on Y‐TZP‐19.9 vol% 64S surfaces appeared to promote the osteogenic potential of UMR‐106 cells.

Structure, dielectric properties of low-temperature-sintering BaTiO3-based glass–ceramics for energy storage

The 0.85BaTiO3–0.15Bi(Mg[Formula: see text]Nb[Formula: see text])O3 (BTBMN) ceramics with low-melting-temperature B2O3–Na2B4O7–Na2SiO3 (BNN) glass addition were prepared by the solid state method. The composition of the glass–ceramics was BTBMN–[Formula: see text] wt.% BNN ([Formula: see text], 1, 3, 5, 7, 9, 12, 15; abbreviated as BG). The sintering characteristics, phase structure, microstructure, dielectric properties and energy storage properties were systematically investigated. The sintering temperature of BTBMN ceramics was greatly reduced by the addition of BNN glass. The second-phase BaTi(BO[Formula: see text] was observed in the BG system until the glass content reached 15[Formula: see text]wt.%. The addition of BNN glass significantly reduces the grain size of BTBMN ceramics. With the increase of BNN glass content, dielectric constant of BG glass–ceramics at 1[Formula: see text]kHz gradually decreased, the maximum dielectric constant ([Formula: see text] of BG glass–ceramics gradually decreased, while the temperature corresponding to the maximum dielectric constant ([Formula: see text] increased, the ferroelectric relaxation behavior decreased and the temperature stability of the dielectric constant gradually improved. As the BNN glass content increased, the breakdown electric field strength (BDS) of BG glass–ceramics increased first and then decreased, and the polarization values reduced gradually, while the trend of energy storage performance is similar to BDS. When the BNN glass content was 3[Formula: see text]wt.%, the energy storage properties of the BG glass–ceramics were optimal, and a recoverable energy storage density ([Formula: see text]) of 1.26[Formula: see text]J/cm3 and an energy storage efficiency ([Formula: see text]) of 80.9% were obtained at the electric field strength of 220[Formula: see text]kV/cm. The results showed that BG glass–ceramics were promising for energy storage capacitors.

Mechanicaland morphological properties of DGEBA/SiO2 reinforced with fiberglass at room temperature

In this work some mechanical properties of epoxy resin (DGEBA)/silica oxide (SiO2) reinforced with different weight percentage (5, 10 and 15) fiberglass investigated. A homogeneous solid colorless samples were prepared at room temperature using disposable stirrer. The study used the comparison of fiberglass different percentage concentration in order to improve strength and tenacity. Moreover, the effect of silica oxide presence in order to improve the interface surface. The results showed that (DGEBA) epoxy resin with 15% fiber glass has high tensile strength, impact and hardness. Furthermore, the addition of fiber glass improves the fracture toughness of the epoxy resin (DGEBA) and the amount of toughness. Besides, the presence of silica oxide within the sample structure led to greater coherence between the fiberglass and other parts of the composite, this is illustrated by SEM images for selected samples.

Effect of Sintering Temperature and AR Glass Addition towards Physical Properties of Porcelain Ceramic for Sewer Pipes Application

The current work is aimed to investigate significant phase changes at certain sintering temperature in manufacturing ceramic pipes for sewer application. The use of porcelain ceramic reinforced with milled Alkali Resistant (AR) fiberglass (3 wt%, 6 wt%, 9 wt% and 12 wt%) was determined in this study. Both of raw materials were turned into powder to conduct thermal analysis and produce a compact sample. The powder was compacted by uniaxial pressing technique to examine the analysis of volume shrinkage. Volume shrinkage was done by measuring the dimension of green body and sintered sample (900°C, 1000°C 1100°C and 1200°C). The image of microstructural morphology was observed by Scanning Electron Microscope. TG graph indicates large amount of mass loss found to be 75% between 450°C to 800°C for porcelain and all mixtures. While DT graph reveals the endothermic shift produce at 250°C. The maximum volume shrinkage was obtained at 1200°C which is 31.7% with 3 wt% AR glass addition. The microstructural image proved the correlation to volume shrinkage. The presence of glassy phase demonstrates the formation of eutectic where shrinking particle takes place to construct dense sample.

In vitro performance of a nanobiocomposite scaffold containing boron-modified bioactive glass nanoparticles for dentin regeneration.

Every year, many dental restoration methods are carried out in the world and most of them do not succeed. High cost of these restorations and rejection possibility of the implants are main drawbacks. For this reason, a regenerative approach for repairing the damaged dentin-pulp complex or generating a new tissue is needed. In this study, the potential of three-dimensional cellulose acetate/oxidized pullulan/gelatin-based dentin-like constructs containing 10 or 20% bioactive glass nanoparticles was studied to explore their potential for dentin regeneration. Three-dimensional nano biocomposite structures were prepared by freeze-drying/metal mold pressing methods and characterized by in vitro degradation analysis, water absorption capacity and porosity measurements, scanning electron microscopy, in vitro biomineralization analysis. During one-month incubation in phosphate buffered saline solution at 37°C, scaffolds lost about 25-30% of their weight and water absorption capacity gradually decreased with time. Scanning electron microscopy examinations showed that mean diameter of the tubular structures was about 420 µm and the distance between walls of the tubules was around 560 µm. Calcium phosphate precipitates were formed on scaffolds surfaces treated with simulated body fluid, which was enhanced by boron-modified bioactive glass addition. For cell culture studies human dental pulp stem cells were isolated from patient teeth. An improvement in cellular viability was observed for different groups over the incubation period with the highest human dental pulp stem cells viability on B7-20 scaffolds. ICP-OES analysis revealed that concentration of boron ion released from the scaffolds was between 0.2 and 1.1 mM, which was below toxic levels. Alkaline phosphatase activity and intracellular calcium amounts significantly increased 14 days after incubation with highest values in B14-10 group. Von Kossa staining revealed higher levels of mineral deposition in these groups. In this work, results indicated that developed dentin-like constructs are promising for dentin regeneration owing to presence of boron-modified bioactive glass nanoparticles.

Effective dielectric loss (tan δ) reduction of CaCu3Ti4O12 (CCTO) via various addition of glasses

AbstractAddition of various glasses has successfully reduced tan δ of CCTO‐based ceramics. Less amounts (0‐1.0 wt%) of glasses (BaO‐SrO‐Nb2O5‐B2O3‐SiO2 [BSNBS] and SrO‐B2O3‐SiO2 [SBS], respectively) were added into pure CCTO and sintered at 1040°C for 10 hours. The phase formation and microstructure of each sample were characterized using X‐ray diffraction and scanning electron microscopy, respectively. The dielectric behavior of the samples was measured at 1 MHz. The addition of BSNBS and SBS glasses (≤0.5 wt%) successfully reduced tan δ of CCTO from 0.5 until 0.4 and 0.39, respectively, and simultaneously increased εr. Smaller tan δ and ɛr were further obtained when the added glasses were more than 0.5 wt%. These behaviors were due to segregation of glasses together with precipitation of CuO which decreased the grain size, and caused the presence of pores at grain boundaries. Therefore, small amount of various additions of glasses could modify the CCTO dielectric properties.

Effect of Addition of Amorphous Glass (Soda Lime Glass) on Sintering Process and Properties of Alumina Ceramics

The composition of amorphous glass was varried such as 0, 5 and 10 % wt. also temperature of sintering was varried from 1200 to 1400 °C. The γ-Al2O3 powder (p.a) and amorphous glass from soda lime glass were mixed and milled by using a ball mill for 24 hours, and then dried at 100 deg.C. Then, the dried powders were mixed with 2 % PVA as a binder, then, the powders ware put into a dies mold and pressed with a pressure of 40 MPa. The pellet samples were sintered by using electrical furnace Thermolyne with heating rate 10°C/minute and holding time at each sintering temperature for 2 hours. The characterization of the sintered sample was done such as measurement of density, porosity, vickers hardness, and analysis of crystal structure. The characterization results show that the highest density value of 3.36 g/cu.cm and the lowest porosity value of 1.06 % obtained at 1400 °C sintering temperature with 10% additive. While the samples without additive have density value about 2.37 g/cu.cm and its porosity value about 20% at 1400 °C sintering temperature. Similarly, the highest hardness value was achieved at 775 Hv on samples with 10% additive and sintering temperature of 1400 °C. The XRD analysis showed that samples with SiO2 additive up to 10% did not cause reaction and did not cause new phase. The phase that appears only the corundum phase (α-Al2O3). The sintering process of Alumina Ceramic the presence of SiO2 additive can be accelerated with lower temperatures.