Glass-ceramic Powder Research Articles

Upconversion random lasing in Er3+/Yb3+ co-doped germanate-lead-magnesium glass-ceramics

Upconversion Random Laser (UC-RL) based on Yb3+ and Er3+ co-doped germanate-lead-magnesium (GPM) glass-ceramic powder is reported for the first time. Following the glass fabrication by a conventional melt-quenching technique, the samples were devitrified at 815 °C for 4 and 8 h, respectively. The samples were grained and excited using an optical parametric oscillator (pulses of 7 ns) tuned at 980 nm, in resonance with the Yb3+ transition 2F7/2 → 2F5/2 and with the Er3+ transition 4I15/2 → 4I11/2. The input-output curves revealed RL emission at ∼547 nm for an energy fluence excitation threshold (EFE)th of about 0.6 mJ/mm2 for GPM sample and ∼0.45 and ∼0.20 mJ/mm2 for samples heat-treated for 4 and 8h, respectively. For excitation above the (EFE)th, a fast pulse in the nanosecond range is observed, corroborating the lasing process. The RL feedback mechanism is due to the light reflections in the particles-air interfaces and to reflections between the glass-crystallites interfaces. Additionally, the Replica Symmetry Breaking (RSB) phenomenon was observed for all samples excited above the (EFE)th. Pearson correlation coefficients (PCC) maps were also obtained and showed that RL modes were increasingly correlated above (EFE)th. No reduction of the emission linewidth was observed above (EFE)th, due to the inhomogeneous broadening that is very large in vitreous matrices. This is the first time that RSB and PCC maps are reported for an UC-RL.

3D printing of cordierite glass-ceramics

Compared to traditional ceramic materials, glass-ceramics can also exhibit superior properties and are now widely used in cutting-edge national defense industries technology, aerospace, electronics, construction, and other fields. In this study, it is for the first time reported that novel photopolymerization 3D printable slurries using cordierite glass ceramic powder were prepared. The effects of slurry properties and printing process parameters on the warpage of the printed samples were studied. Cordierite glass-ceramic parts fabricated using photopolymerization 3D printing and heat treatment processes were studied to evaluate the effects of sintering parameters on the properties of the samples. The obtained additively manufactured cordierite glass-ceramics exhibit excellent microstructural and mechanical properties, with a maximum bending strength of 181 MPa, an increase of 95.66 % compared to that of the previously reported 3D printed cordierite ceramics. The underlying mechanisms of the glass and ceramic phase characteristics influence the density and the mechanical properties during and after the courses of sintering were also investigated and unveiled in detail. This study provides a viable method for manufacturing complex-shaped cordierite glass-ceramic components using 3D printing.

Enhancement in the induction heating efficacy of sol-gel derived SiO2-CaO-Na2O-P2O5 bioglass-ceramics by incorporating magnetite nanoparticles.

Magnetite (Fe3O4) nanoparticle (MNP)-substituted glass-ceramic (MSGC) powders with compositions of (45 - x)SiO2-24.5CaO-24.5Na2O-6P2O5-xFe3O4 (x = 5, 8, and 10 wt%) have been prepared by a sol-gel route by introducing Fe3O4 nanoparticles during the synthesis. The X-ray diffraction patterns of the as-prepared MSGC nanopowders revealed the presence of combeite (Na2Ca2Si3O9), magnetite, and sodium nitrate (NaNO3) crystalline phases. Heat-treatment up to 700 °C for 1 h resulted in the complete dissolution of NaNO3 along with partial conversion of magnetite into hematite (α-Fe2O3). Optimal heat-treatment of the MSGC powders at 550 °C for 1 h yielded the highest relative percentage of magnetite (without hematite) with some residual NaNO3. The saturation magnetization and heat generation capacity of the MSGC fluids increased with an increase in the MNP content. The in vitro bioactivity of the MSGC pellets was evaluated by monitoring the pH and the formation of a hydroxyapatite surface layer upon immersion in modified simulated body fluid. Proliferation of MG-63 osteoblast cells indicated that all of the MSGC compositions were non-toxic and MSGC with 10 wt% MNPs exhibited extraordinarily high cell viability. The MSGC with 10 wt% MNPs demonstrated optimal characteristics in terms of cell viability, magnetic properties, and induction heating capacity, which surpass those of the commercial magnetic fluid FluidMag-CT employed in hyperthermia treatment.

The study of near-net shape lithium aluminosilicate glass-ceramics by direct ink writing

3D printing, a competitive manufacturing technology, has opened up new possibilities for fabricating complex structure ceramic components, but near-net forming is still difficult. This work presented a kind of near-net forming lithium aluminosilicate (LAS) glass-ceramics using direct ink writing (DIW) method by controlling thermal shrinkage. To achieve this goal, a high solid-loading ink was prepared using low thermal expansion LAS glass-ceramic powder containing β-spodumene as raw material. And we comprehensively evaluated the effects of the rheological properties of the slurry and sintering process on the thermal and mechanical performances. Attributed to the restricted sintering activity and thermal deformation of LAS glass-ceramic particles, the 3D-printed samples sintered at 1300 ◦C for 2 h showed an average linear shrinkage of 0.84% with a flexural strength of 45.59 ± 2.82 MPa and a compressive strength of 65.58 ± 3.99 MPa, respectively. The results suggested that LAS glass-ceramics were excellent candidate materials for near-net forming 3D printing.

Fast ion conduction and stable [Na-Si-P] glass-ceramic solid electrolyte mixed with hafnium and scandium ions: Application to Na-ion full cell

NASICON type glass and glass-ceramic electrolyte materials have become very attractive choices recently to integrate into any Na+ ion storage system. This investigates glass and glass-ceramic electrolytes using the formula: 45(Na2O + NaF)-10SiO2-35P2O5-(10-x)HfO2-xSc2O3 (labeled as [NSP]90(10-x)HfScx; x = 0, 2, 4, 6, 8, 10 mol%) via the high energy mechanical milling followed by heat treating for different schedules. The thermal stability parameter (ΔT = Tc-Tg) and bulk conductivity are obtained to be highest for [NSP]90(10-x)HfScx glass electrolyte before and after heat treatment. XRD results revealed of Glass-ceramic powder that NASICON type Na3Sc2(PO4)3 and triclinic Na2HfSi2O7 major crystalline phases, which are reported to be highly conductive and stable. [NSP]90Hf4Sc6 −12 h glass-ceramic electrolyte stabilizes more against Na- metal than its corresponding [NSP]90 (10-x)HfScx glass electrolyte. The lowest interfacial resistance of [NSP]90Hf4Sc6 −12 h is observed than its pristine ell, directly ascribes the compatibility of Na metal-[NSP]90Hf4Sc6-12 h/Na electrolyte combination. The irreversible capacity and stability of full cell NVMP/[NSP]90Hf4Sc6/NVZn is also explored in light of the oxidation and redox reaction behavior.

Assessment of sol-gel derived iron oxide substituted 45S5 bioglass-ceramics for biomedical applications.

Magnetic bioactive glass-ceramic (MGC) powders with nominal compositions of (45 - x)SiO224.5CaO24.5Na2O6P2O5xFe2O3 (x = 2, 4, 6, 8, 10, and 15 wt%) have been synthesized by a sol-gel route by systematically substituting silicon dioxide with iron oxide in Hench's 45S5 glass composition. Powder X-ray diffraction studies revealed a variation in the percentage of combeite (Ca2Na2Si3O9), magnetite (Fe3O4), and hematite (Fe2O3) nanocrystalline phases in MGC powders as a function of composition. Zeta potential measurements showed that MGC containing up to 10 wt% iron oxide formed stable suspensions. The saturation magnetization and heat generation capacity of MGC fluids increased with an increase in iron oxide content. Degradation of MGC powders was investigated in phosphate buffered saline (PBS). The in vitro bioactivity of the MGC powders taken in pellet form was confirmed by observing the pH variation as well as hydroxyapatite layer (HAp) formation upon soaking in modified simulated body fluid. These studies showed a decrement in the overall bioactivity in samples with high iron oxide content due to the proportional decrease in the silanol group. Monitoring the proliferation of MG-63 osteoblast cells in Dulbecco's Modified Eagle Medium (DMEM) revealed that MGC with up to 10 wt% iron oxide exhibited acceptable viability. The systematic study revealed that the MGC with 10 wt% iron oxide exhibited optimal cell viability, magnetic properties and induction heating capacity, which were better than those of FluidMag-CT, which is used for hyperthermia treatment.

Effect of Sandblasting with Fluorapatite Glass-ceramic Powder and Chemical Primers/Adhesives on Shear Bond Strength of Indirect Repairing Composite to Zirconia.

To investigate the effect of sandblasting with fluorapatite glass-ceramic (FGC) powder on zirconia surface roughness, crystallinity, and shear bond strength (SBS) of indirect repairing composite to zirconia using different primers/adhesives. Zirconia blocks were treated as follows: no treatment (control group), blasting with 30-μm silica-coated alumina (CoJet group), and blasting with FGC powder (FGC group). The surface topography, silica content, roughness, and crystallinity of treated zirconia surfaces were analyzed by a scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), an optical profilometer, and X-ray diffraction (XRD), respectively. Four primers/adhesives (Monobond Plus, Calibra Silane, Futurabond M+, and Scotchbond Universal) were compared to bond precured resin composite to zirconia groups using Multilink Automix resin cement. Bonded specimens were thermocycled for 10,000 cycles and tested in SBS and the modes of failure were recorded. The effect of different surface treatments and primers/adhesives on SBS results were statistically analyzed using two-way ANOVA and Bonferroni post-hoc tests (α=0.05). Both CoJet and FGC groups showed rough surfaces with a higher content of silica in FGC, but less monoclinic crystals, compared to the CoJet group. The highest mean SBS was found in the FGC group treated with Monobond Plus compared to CoJet and Control groups. Adhesive failure was predominant in control groups, while combined failure was found in the CoJet and FGC groups regardless of the primers/adhesives employed. Sandblasting zirconia with FGC powder increased SBS of resin composite to zirconia with lower monoclinic phase transformation compared to CoJet sand. Monobond Plus reported the highest means of SBS values compared to other primers/adhesives.

Glass-ceramic route to NASICON-type Na Ti2(PO4)3 electrodes for Na-ion batteries

Glass-ceramic processes to prepare NASICON-type Na x Ti 2 (PO 4 ) 3 , which is an anode candidate for sodium-ion batteries, from 30Na 2 O–40TiO 2 –30P 2 O 5 glass have been investigated with varied atmospheric conditions. By annealing in the inert (N 2 ) atmosphere, the glass started crystalizing into NASICON-type NaTi 2 (PO 4 ) 3 with rhombohedral symmetry at ∼600 °C followed by crystallization of other phases to be multiphase mixtures at higher temperatures. In contrast, in the reducing (5% H 2 /Ar) atmosphere, NASICON-type Na 3 Ti 2 (PO 4 ) 3 with triclinic symmetry is crystallized at >∼800 °C. The formation of Na 3 Ti 2 (PO 4 ) 3 is associated with a loss of excess oxygens in the initial glass composition and a reduction of Ti from Ti 4+ to Ti 3+ . The reduction process upon the glass-to-ceramic conversion was traced by in-situ observation during the thermogravimetric analysis. It is also revealed that the electrochemical Na + -storage capabilities of the glass-ceramic electrodes are correlated with the Na-ion occupancy between these two phases, and their phase fractions affect the charge-discharge properties of Na-ion cells. Finer glass-ceramic powders could improve the electrochemical properties and achieve almost 80% of its theoretical capacity.

Powder 3D Printing of Bone Scaffolds with Uniform and Gradient Pore Sizes Using Cuttlebone-Derived Calcium Phosphate and Glass-Ceramic.

The pore geometry of bone scaffolds has a major impact on their cellular response; for this reason, 3D printing is an attractive technology for bone tissue engineering, as it allows for the full control and design of the porosity. Calcium phosphate materials synthesized from natural sources have recently attracted a certain interest because of their similarity to natural bone, and they were found to show better bioactivity than synthetic compounds. Nevertheless, these materials are very challenging to be processed by 3D printing due to technological issues related to their nanometric size. In this work, bone scaffolds with different pore geometries, with a uniform size or with a size gradient, were fabricated by binder jetting 3D printing using a biphasic calcium phosphate (BCP) nanopowder derived from cuttlebones. To do so, the nanopowder was mixed with a glass-ceramic powder with a larger particle size (45–100 µm) in 1:10 weight proportions. Pure AP40mod scaffolds were also printed. The sintered scaffolds were shown to be composed mainly by hydroxyapatite (HA) and wollastonite, with the amount of HA being larger when the nanopowder was added because BCP transforms into HA during sintering at 1150 °C. The addition of bio-derived powder increases the porosity from 60% to 70%, with this indicating that the nanoparticles slow down the glass-ceramic densification. Human mesenchymal stem cells were seeded on the scaffolds to test the bioactivity in vitro. The cells’ number and metabolic activity were analyzed after 3, 5 and 10 days of culturing. The cellular behavior was found to be very similar for samples with different pore geometries and compositions. However, while the cell number was constantly increasing, the metabolic activity on the scaffolds with gradient pores and cuttlebone-derived powder decreased over time, which might be a sign of cell differentiation. Generally, all scaffolds promoted fast cell adhesion and proliferation, which were found to penetrate and colonize the 3D porous structure.

Zr doped NASICON-type LATP glass-ceramic as a super-thin coating onto deoxidized carbon wrapped CNT-S cathode for lithium-sulphur battery

Rechargeable lithium–sulphur (Li–S) battery is one of the best candidates for the next generation of high-energy-storage systems. However, widespread application of Li–S battery is being restricted by the solubility and migration of the reaction intermediates in both discharge and charge processes. In this paper, we report a dual-phase electrolyte-based Li-S battery with high capacity and safety performance. With a lithium superionic conductor coating on the deoxidized carbon wrapped carbon nanotube-sulphur (CNT-S) cathode, there is no obvious decay in capacity during the long-term cycles for the assembled dual-phase electrolyte-based Li–S battery, and the discharge capacities achieved after the fortieth cycle are observed to return back to the level of the initial cycle. The sub-micron crystallized NASICON-type glass-ceramic powders with high purity are synthesized by a modified sol-gel method. Compared to the best value reported recently, an order of magnitude enhancement in total conductivity under room temperature is obtained in the doped sample using the process. By introducing this super high lithium-ion conductor to the particular battery architecture and combining it with the developed high-performance positive electrode, the assembled dual-phase electrolyte-based Li–S battery exhibits an efficient utilization of active materials and outstanding high-rate discharge ability, which is promising for possible commercial exploitation and practical applications.

Bioactivity and biodegradability of high temperature sintered 58S ceramics

Bioactive glasses are often considered in bone tissue engineering applications where mechanical strength is essential. As such, bioactive glass scaffolds are often sintered to improve mechanical strength. However, sintering can lead to crystallization, which reduces bioactivity and biodegradability. It has generally been considered that amorphous biomaterials exhibit better bioactivity. However, the in-vitro bioactivity and biodegradability of the sintered 58S made from initial amorphous powder and partially crystalline powder with the same chemical compositions (60SiO2-36CaO-4P2O5 (mol%)) have not been compared before.In this study, 58S bioactive glass (fully amorphous) and glass-ceramic (partially crystallized) powders were synthesized using the sol-gel process, followed by heat-treating at 600 °C for 3 h (calcination). The powders were mixed with carboxymethyl cellulose solution as a binder, shaped in a cylindrical mold, dried, and then sintered at 1100 °C for 5 h. The in-vitro bioactivity and biodegradability of the sintered samples were assessed in simulated body fluid (SBF) for times up to 28 days. The specimens were investigated before and after immersion in SBF using X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM), and Fourier transform infrared spectroscopy (FT-IR). The In-vitro bioactivity and biodegradability rate of the sintered 58S produced from the glass ceramic powder were higher than that from fully amorphous powder. This study shows that the initial structure after calcination is important and affects the subsequent crystallization during sintering. Therefore, crystallinity and formation of hydroxyapatite after calcination are important controlling mechanisms that can increase the bioactivity and biodegradability rate of sintered 58S.

Microstructure and Mechanical Properties of Li2Si2O5 Whisker-Reinforced Glass-Ceramics

Lithium disilicate (Li2Si2O5) glass-ceramics are an ideal material for dental restoration; however, their intrinsic brittleness and low defect tolerance limit the scope of their clinical applications. In this study, Li2Si2O5 whiskers were creatively synthesized via a mild-condition hydrothermal reaction. Self-reinforced Li2Si2O5 glass-ceramics were sintered by introducing the Li2Si2O5 whiskers, and their effects on phase, microstructure, and mechanical properties were systematically studied. The crystal-growth and toughening mechanisms were also discussed. The results showed that the Li2Si2O5 whiskers played an important role in inducing crystallization, and improving the microstructure and properties of the glass-ceramics. With increasing amounts of Li2Si2O5 whiskers, the crystallinities increased slightly, and the average crystal size also increased. The microstructure was composed of crystals of bimodal size distributions, in which some large, rod-like Li2Si2O5 crystals epitaxially grew along with the whiskers, and small crystals directly crystallized from the parent glass-ceramic powders. The Li2Si2O5 glass-ceramics exhibited high flexural strength (389.5 ± 11.77 MPa, LDW3), and fracture toughness (3.46 ± 0.10 MPa·m1/2, LDW5). The improved properties were attributed mainly to crack deflection and bridge-toughening mechanisms.

Influence of R=Y, Gd, Sm on Crystallization and Sodium Ion Conductivity of Na5RSi4O12 Phase.

New sodium-based battery concepts require solid electrolytes as ion conducting separators. Besides NaSICON and β-Al2O3 in the Na2O-R2O3-SiO2 system (R = rare earth), a rarely noticed glass-ceramic solid electrolyte with the composition Na5RSi4O12 (N5-type) exists. The present study addresses the investigation of the ionic conductivity of Na5RSi4O12 solid electrolytes sintered from pre-crystallized glass-ceramic powders. The sintering behavior (optical dilatometry), the microstructure (SEM/EDX), and phase composition (XRD), as well as electrochemical properties (impedance spectroscopy), were investigated. To evaluate the effect of the ionic radii, Y, Sm and Gd rare elements were chosen. All compositions were successfully synthesized to fully densified compacts having the corresponding conducting N5-type phase as the main component. The densification behavior was in agreement with the melting point, which decreased with increasing ionic radii and specific cell volume. Alternatively, the ionic conductivities of N5-phases decreased from Y to Gd and Sm containing samples. The highest ionic conductivity of 1.82 × 10−3 S cm−1 at 20 °C was obtained for Na5YSi4O12 composition. The impact of grain boundaries and bulk conductivity on measured values is discussed. A powder-based synthesis method of this glass-ceramic solid electrolyte using different rare earth elements opens possibilities for optimizing ionic conductivity and scalable technological processing by tape casting.

M1 - Fracture Toughness and Fractal Dimension of Two Dental Glass-Ceramics

Studies have reported the fractal dimensional increment of glass and glass-ceramic fracture surfaces. The objective of this study was to determine the relationship between fracture toughness and fractal dimensional increment of two types of dental glass-ceramics with different volume fraction of crystals and different fracture surface roughness. Fifteen bar-shaped specimens were prepared from lithium disilicate (LDS) by sectioning the blocks (IPS e.max CAD, Ivoclar Vivadent). Ten beams were prepared by mixing and layering the nanofluorapatite (NFA) glass-ceramic powder (IPS e.max Ceram, Ivoclar Vivadent). One face of each of the specimens was indented using a Knoop diamond at 25 N (LDS) or 10 N (NFA) followed by loading in deionized water in 4-point, or 3-point flexure, respectively, until failure. Fracture surfaces were analyzed using scanning electron microscope (SEM). Fracture toughness (Kc) was calculated using the surface crack in flexure (SCF) technique (ASTM C1421). Epoxy replicas of the fracture surfaces were scanned using the atomic force microscope (AFM) followed by noise filtering. The FRACTALS software was used to determine the fractal dimensional increment (D*) by the Minkowski cover algorithm. In addition, surface roughness was computed from the AFM scans using the Gwyddion software. The median (25%, 75% quartiles) fracture toughness of LDS and NFA bars were 1.62 (1.59, 1.69) MPam1/2 and 0.68 (0.66, 0.74) MPam1/2, respectively. The median fractal dimension (D) value (25%, 75% quartiles) before and after noise filtering for LDS were 2.16 (2.15, 2.17) and 2.14 (2.14, 2.15), respectively, and for NFA were 2.29 (2.21, 2.38) and 2.17 (2.17, 2.18), respectively. The NFA follows the regression model (Y=1.99 X) between Kc and sqrt. D* for glasses as previous studies, but the LDS deviated from the model. The median (25%, 75% quartiles) surface roughness before and after noise filtering for LDS were 139 (119, 188) nm and 137 (118, 187) nm and for NFA were 7 (6, 15) nm and 7 (6, 15) nm, respectively. Noise filtering successfully eliminated noise from the AFM scans of the material with smooth fracture surfaces (NFA), resulting in a decrease in measured fractal dimension. The LDS data deviated from the model because of toughening due to crack bridging. Fractal analysis with noise filtering can be used to estimate the fracture toughness of dental glass-ceramics that do not exhibit crack bridging.

Potential utilization of waste materials for the production of green concrete: A review

The concrete which is made with waste materials which are not harmful for the environment, use limited energy in their manufacturing and emits a less amount of carbon dioxide, is known as Green Concrete. Production of cement emits about 8–10% of the world's total Carbon Dioxide which is a major cause of pollution and impacting the environment. In this review paper different waste materials have been considered which can be used in replacement of cement. The basic characteristics of major concerning wastes like fly ash, silica fumes, waste glass powder and ceramic powder have been compared. Comprehensive data from various researchers has been compared and reviewed in order to show the potential utilization of these wastes into value added products. To provide a road map for future researchers, wide range of their physic-chemical properties has been prepared, as it was already clear that the properties of wastes may differ with respect to place of origin.

Additive manufacturing of lithium aluminosilicate glass-ceramic/metal 3D electronic components via multiple material laser powder bed fusion

Multiple material additive manufacturing technology with the capability to integrate glass-ceramic and metallic materials is essential to the development of high-performance functional components for high temperature applications. Here we show the feasibility and characteristics of additively manufactured glass-ceramic/metal 3D electronic components via single-process multiple material laser powder bed fusion (MMLPBF). Copper (II) oxide (CuO) powder is mixed with α-spodumene (lithium aluminosilicate, Li 2 O·Al 2 O 3 ·4SiO 2 ) glass-ceramic powder to improve the laser absorbance, reduce the melting point of glass-ceramic to match that of copper and to improve bonding between copper and the glass-ceramic. Up to 92% relative density of the glass-ceramic is realized. The monoclinic crystal α-spodumene has been transformed to tetragonal crystal β-spodumene after laser melting. Sodium chloride (NaCl) and graphite mixed powder is printed as the substrate for the glass-ceramic component for its rapid removal. Embedded conductive copper wires and plates as the main conductive structures are successfully built within the glass-ceramic from powder feedstocks. The electrical resistivity of the printed copper structures is examined. An embedded multiple layer electric circuit, a capacitor and a temperature sensor are successfully printed and tested. • First demonstration of printing glass-ceramic/metal 3D electronic components via LPBF. • Copper oxide is added to the glass-ceramic powder to tune the material property. • Salt is used as the interface layer to the base plate for ease of removal. • 3D circuit, capacitor and temperature sensor are imbedded in the glass/ceramic.

Influence of Ca/Al ratio on physical and dielectric properties of Al2O3/CaO-B2O3-SiO2 glass-ceramics composite coatings prepared by high enthalpy atmospheric plasma spraying

The dielectric layer plays a key role in regulating electromagnetic wave broadband scattering based on meta-surface technology. Herein, the physical properties of composite powder, prepared by spray drying of CaO-B2O3-SiO2 (CBS) glass-ceramic powder and Al2O3 in different mass ratios, are systematically investigated. Meanwhile, a high enthalpy atmospheric plasma spraying equipment is utilized to prepare CBS/Al2O3 composite coatings, and the morphology, physical properties and dielectric properties of the composite coating are analyzed. The XRD and DSC data of the composite coating reveal that the crystallization behavior of β-CaSiO3 and CaB2O4 gradually disappear with the increase of Al2O3 content. Hence, only CaAl2Si2O8 phase is observed during heat treatment. The experimental results confirm that the dielectric properties of CBS/Al2O3 composite coating conform to the rule of mixture for composite materials. Also, the dielectric properties are affected by porosity and crystallization rate.

Mechanical properties and wear behaviors analysis of fluorapatite glass-ceramics based on stereolithography 3D printing

Stereolithography (SL) 3D printing of ceramic materials is a promising forming technology to prepare denture with complex shape in the dental field. But the SL formed parts often have inferior mechanical properties than traditional forming method, and the debinding process is time assuming, limiting the clinical application of the technology. In this paper, a novel fluorapatite (FAp) glass-ceramics samples were fabricated through SL 3D printing based on self-made glass-ceramic powders. The effect of laser power and scanning speed on mechanical properties and tribological properties of FAp glass-ceramics were investigated. Phase compositions and microstructure of specimens were characterized by X-ray diffractometer and scanning electron microscope. The microhardness, flexural strength, elastic modulus and tribological performances of the SL samples were tested and compared with that of traditional dry pressing formed samples. The results showed that with the appropriate laser parameters and a relatively short debinding time, the SL formed glass-ceramics had microhardness, flexural strength, and elastic modulus of 772.05 Hv, 205.97 MPa, and 97.06 GPa, respectively, which exceeded that of traditional formed samples. The results reveal that it is possible to efficiently obtain FAp glass-ceramics with excellent mechanical and tribological performance by SL 3D printing process with appropriate parameters.

Proportioning of green mortar by using different cementitious materials

Pozzolanic materials are used extensively at the present time due to their availability in large quantities, especially materials that are considered waste from construction works and industrial waste. In this research, various pozzolanic materials were used, such as glass powder; ceramic powder, and brick powder, seven mortar mixes (M, M1, M2, M3, M4, M5 and M6). This research has been prepared and focuses on the impact of using these materials in mortars as cement replacement. M1, M2, M3 The cement was replaced as 30, 35, 40% by glass powder and ceramic powder (10% glass with 20, 25 and 30% ceramic powder) by weight of cement. M4, M5, M6 was replaced as 30, 35, 40% by glass powder and brick powder (10% glass with 20, 25, 30% brick powder) the cement by weight. The specimens were cast in a cube of 50 x 50 x 50 mm and the water curing regime was applied until the testing age. The fineness of the powder used in glass, ceramics and bricks is less than 45μm. Changes in compressive intensity for both samples have been examined. The optimal replacement that provided the better strength was found to be 40 percent replacement (10% glass with 30% brick powder).

Preliminary evaluation of the in vitro biocompatibility of magnetic bone cement composites

Polymethyl methacrylate (PMMA) bone cement with the addition of magnetic glass-ceramic (MGC) has attracted much attention for the treatment of deep-seated tumour tissues. Since PMMA bone cement has been a gold standard in orthopaedic surgery and magnetic glass-ceramic can generate heat under a magnetic field, the combination of these two materials could show promising results for magnetic induction hyperthermia treatment.Thus, magnetic glass-ceramic powders were mixed with the commercial Palacos MV® cement in amounts up to 40 ​wt%. The resulted magnetic bone cement composites were assessed in vitro for bioactivity and cytocompatibility. In vitro bioactivity was evaluated using a simulated body fluid (SBF). The effect of magnetic cement composition on the viability of cancerous and normal (non-cancerous) cells was assessed using U2OS osteosarcoma and OBS human osteoblast cells, respectively. Cell attachment to the surface of the magnetic composite samples was observed using fluorescence and scanning electron microscopy.The magnetic composites showed bioactive properties. After two weeks of immersion in SBF, a non-uniform layer of hydroxyapatite was observed on their surface. Alamar blue cytotoxicity tests after 3 days in cell culture indicated that magnetic composites are cytotoxic for U2OS cancer cells, but they are cytocompatible to OBS normal cells.