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Materials with ideal thermal dissipation can prevent electronic devices from overheating and sustaining internal damage. However, obtaining passive heat sink materials with a well-distributed thermal transport network remained challenging. In this study, carbon nanotubes (CNTs) reinforced zinc silicate (Zn 2 SiO 4) composites (CNTs/ZS) were fabricated via colloidal processing and pressureless sintering. The CNTs was first dispersed in 1,2,3,4-tetrahydronapathalene (C 10 H 12) through sonication, before composite-mixing and densification with zinc silicate ceramic. It revealed that the dispersed CNTs simultaneously improved the mechanical and thermal properties of the composites, along with reducing relative density. The Vickers hardness, thermal diffusivity, and thermal conductivity of the optimized composite containing 1.0 wt% CNTs increased by 42%, 179%, and 537%, respectively, compared to the pristine ZS. The SEM observation on the 1.0 wt% CNTs/ZS composite surface determined that the area fraction of the CNTs inclusions was approximately 60%, which was advantageous for phonon propagation and electron transmission path. The combined effect of the phonon and electron transmission path outperformed the polycrystalline-induced Umklapp scattering and porosity-induced phonon-pore scattering, which were identified as obstacles to the heat-transfer process. Thus, this CNTs reinforcement through colloidal processing can be a strategy for designing of efficient silicate-based heatsink candidates in optoelectronic applications. [Display omitted] • Low density CNTs/ZS composite exhibited higher surface hardness than bare ZS composite. • ZS ceramic with 1.0 wt% CNTs reinforcement improved the thermal diffusivity from 0.25 to 0.70 mm2s-1. • Carbon nanotubes (CNTs) was well-dispersed in tetralin before composite-mixing with ZS ceramic. • High resolution XPS spectra reveal the formation of Si–C bonding in the composite. [ABSTRACT FROM AUTHOR]

In this study, we synthesized Li₂O–B₂O₃–Al₂O₃ glasses incorporating varying amounts of Dy₂O₃ through the melt-quenching method. The glass formulations followed the composition 23Li₂O + (69 - x)B₂O₃ + 8Al₂O₃ + xDy₂O₃, where x was 0, 1, 1.5, 2, 2.5, and 3 mol%. The glass was found to have an amorphous structure through X-ray diffraction analysis, with Fourier-transform infrared spectroscopy revealing the existence of BO₃ and BO₄ structural units. Mass variation and weight loss rates were evaluated using thermogravimetric analysis and differential thermogravimetry. Optical studies indicated that the direct and indirect bandgap energies were between 3.65–3.76 eV and 2.98–3.29 eV, respectively, as the concentration of Dy₂O₃ increased. The Urbach energy showed a decreasing trend with the higher Dy₂O₃ content, indicating improved structural stability and reduced disorder in the glass network. The Phy-X software was used to determine various radiation attenuation parameters for the selected glass samples for photon energies ranging from 0.015 to 15 MeV. As a result, LBAD-3 showed the optimal performance among the samples. At low photon energy, 0.015–0.05 MeV, LAC values varied from 38.56 to 1.89 cm⁻1. The maximum MAC values at 15 keV were recorded as 15.347 cm2/g for the glass samples LBAD-3. At 15 keV, the smallest HVL values are observed to be 0.017 cm, and the highest values for Z eff were found at a low energy photon range (0.015 MeV) with values of 38.73, while the lowest values were found at 9.650 at 15 MeV for LBAD-3 glasses. There was a notable increase in the buildup factor within the 0.1–10 MeV energy range, with a gradual decrease at higher photon energies. Moreover, the computed Σ R values, with a maximum of 0.104 cm⁻1 for the LBAD-3 sample, highlight its strong potential for fast neutron attenuation. The photon shielding capability of the glass was evaluated using the effective removal cross-section, revealing that the glass containing 3 mol% Dy₂O₃ outperformed the other compositions in photon attenuation. This innovative glass system holds the potential for advancing radiation shielding technologies in the future. • We synthesizes Li₂O–B₂O₃–Al₂O₃ glasses doped with varying concentrations of Dy₂O₃. • All glasses exhibit amorphous structure. • FTIR analysis reveals the presence of BO₃ and BO₄ structural units in the glasses. • Urbach energy decreases with increasing Dy₂O₃ content indicates the influence of dysprosium doping on the optical. • The addition of Dy₂O₃ enhances the radiation shielding properties of the glass systems. [ABSTRACT FROM AUTHOR]

The development and fabrication of bioactive glass (bioglass)-ceramics derived from waste materials enhance the mechanical properties of calcium fluoroaluminosilicate based bioglass-ceramics for biomedical applications. This study aims to examine the effect of the Na 2 CO 3 /Al 2 O 3 ratio on the 44SLS-(20-x) Na 2 CO 3 -24ES-6P 2 O 5 -6CaF 2 -xAl 2 O 3 system where x = (0,3,6, and 9 wt%) as well as its mechanical performance. Structural and microstructural properties were analysed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). In the interim, the density of glass ceramic samples was measured using the method of Archimedes. Afterwards, the bioglass ceramics with the Na 2 CO 3 /Al 2 O 3 ratio of 11/9 sintered at 950 °C exhibited excellent results in terms of density that is 2.734 g/cm3. XRD analysis also confirmed the increase in crystallisation of anorthite, fluorapatite and nacaphite. Moreover, SEM analysis revealed the morphology of round-shaped fluorapatite with a variation in the size of sintered glass ceramics. The optimal compressive strength of 136.58 MPa is in the range of human cortical bone. • The new formulation of CFAS derived from waste materials of SLS and ES may reduce the fabrication cost. • Besides, gain the added value of waste material towards more valuable products. • Al 2 O 3 addition as an alternative to improve the mechanical properties of bioglass ceramics. • 136.58 MPa compressive strength is consistent with the typical range found in human cortical bone. [ABSTRACT FROM AUTHOR]

Polytetrafluoroethylene (PTFE) composites filled with recycled borosilicate (rBRS) glass were fabricated for printed circuit board (PCB) substrate application. The rBRS powder prepared via a ball milling technique was dispersed in the PTFE matrix in different volume fractions (5%–25%) to produce the composites through a dry powder mixing technique. The effects of filler content on the composites' structural, dielectric, and thermal properties were examined. Scanning electron microscopy showed that rBRS filler was more dispersed in the composites at lower filler contents. The composites showed excellent microwave properties with relative permittivity of 2.31 and a loss tangent of 0.0018 at the highest filler content of 25%. The composites also revealed a good thermal property with a mean CTE of 60.54 ppm/°C at 25% filler content. Experimental data were compared with theoretical predictions. The results showed that experimental values of relative permittivity agreed with calculated values from regression analysis. It was also found that the logarithmic general mixing model gave an excellent estimate of the loss tangent of the composites. • Recycled borosilicate powder was prepared via ball milling to fill the PTFE matrix. • PTFE/rBRS composites were fabricated via a dry powder mixing method. • Variation of filler content revealed the dielectric and thermal reinforcing effects. [ABSTRACT FROM AUTHOR]

The evolution of imperfect crystal from a highly amorphous structure to an ordered crystalline structure via sintering has demonstrated a significant development onto the thermophysical properties. Therefore, a series of La-doped strontium titanate with different morphological properties have been synthesized via high energy ball milling with subsequent sintering. Doping of lanthanum tends to inhibit the grain growth where a significant reduction of grain size (range from 34 nm to 0.47 μm) could be observed. A large amount of grain boundaries presence with fine grains, resulting from lanthanum doping, has enhanced phonon scattering, thus yielding a low heat propagation in La-doped SrTiO 3. Besides acting as a grain growth inhibitor, lanthanum also acts as a scattering centre due to imperfection created by the doping. The scattering mechanisms significantly decrease the phonon mean free path. Consequently, the thermal diffusivity has been efficiently reduced to 1.1 mm2/s as compared to that of pure SrTiO 3 which showed a value of about 3.8 mm2/s, both observed for the complete phase polycrystalline materials. The systematic development of thermophysical and morphological properties of La-doped SrTiO 3 can be served as a preliminary guide to engineer thermoelectric materials with low thermal diffusivity. • Grain growth was inhibited by lanthanum doping, thus resulting the nanometric grains. • Nanometric grains limit the heat transfer due to the imperfection crystals. • Thermal diffusivity of lanthanum doped was efficiently reduced as compared to pure SrTiO 3. [ABSTRACT FROM AUTHOR]