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Effect of attenuate light on polymerization of ceramic suspensions for stereolithography
摘要： Weak bonding strength between interlayers can seriously affect the quality of ceramic parts manufactured by stereolithography. Therefore, the possibility of using chemical bonds to strengthen the adhesion within these parts and the extent to which may be effective are of interest. Thus, a multi-exposure model was built to illustrate the state of this interface. The secondary conversion of a cured layer defined as conversion rate increment caused by decayed ultraviolet (UV) light in a subsequent exposure was selected to represent the extent of a chemical bond. The level of UV light attenuation occurred when travelling through a suspension layer was determined using the Attenuation Law. When decayed light illuminated a cured layer, it underwent further photopolymerization, which was detected by temperature change. The secondary conversion was affected by parameters including the incident energy dose and the propagating length. Optimization of these parameters helped to achieve higher chemical bond ratio.
关键词： Ceramic stereolithography,Secondary photopolymerization,Multi-exposure model,Light attenuation
更新于2025-09-19 17:15:36
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Spectral radiative properties of skeleton inner structure of ceramic foam based on ordered opal structure model
摘要： In this work, three dimensional periodic ordered opal structures are used to model the inner structures of skeleton of porous ceramic foam. The radii of close-packed spheres range from 0.7 μm to 1.7 μm. The spectral radiative properties are predicted by applying the FDTD method to analyze the radiative transfer inside the skeleton. The characteristics of re?ection spectra and transmission spectra with increasing incident wavelength are analyzed, including the different feature regions constituting the variation curves and the red shift of variation curve with growing size of close-packed spheres. The values and characteristics of absorption peaks surrounding the locations where size parameters are approximate to 1 are compared. The BSDF of scattering power are calculated further. The transformation of transmission in incident direction and re?ection in mirror direction is shown. Then, the distribution of radiation intensity in cross sections parallel to the incident light are compared and the variety from uniform distribution to anisotropic periodic distribution is summarized. The prediction and analysis are bene?t to further researches about the radiative transfer inside the porous ceramic foam.
关键词： Spectral radiative properties,Skeleton of ceramic foam,Opal structure,FDTD
更新于2025-09-19 17:15:36
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Laser induced graphene /ceramic membrane composite: Preparation and characterization
摘要： In this work, laser induced graphene (LIG) was successfully fabricated on microporous ceramic membranes. The surface area, morphology, and chemical characterizations were performed on the LIG layer. Water contact angle measurements showed the hydrophobicity of LIG. Pure water and solvents with different polarities were used to understand the solvent flux behavior of LIG membrane. The LIG membrane showed very high non-polar solvent fluxes and remarkably low water permeability, and thus, the transport through the LIG membrane is related to dipole moment and dielectric constant, represented by solvent polarity. The LIG membrane achieved 90% rejection for 255 nm diameter silica particles, suggesting the presence of submicron size connecting pore channels that dominate the transport mechanism.
关键词： Laser induced graphene,LIG/Ceramic composite,Solvent permeation
更新于2025-09-19 17:13:59
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Spectroscopy and diode-pumped continuous-wave laser operation of Tm:Y2O3 transparent ceramic at cryogenic temperatures
摘要： We present the spectroscopic and laser characteristics of a 3 at.% Tm:Y2O3 transparent ceramic at cryogenic temperatures. An absorption cross section of 4.7 × 10?21 cm2 with a bandwidth of 0.7 nm centered at 793.3 nm and an emission cross section of 29.0 × 10?21 cm2 centered at 1930.9 nm were estimated at 80 K. Continuous-wave laser operation was achieved using broadband and VBG stabilized laser diodes emitting around 793 nm as pump sources. With the VBG pump diode, a maximum output power of 6.4 W was achieved at 80 K corresponding to a slope efficiency of 52.0% with respect to absorbed power.
关键词： cryogenic temperatures,diode-pumped,Tm:Y2O3,spectroscopy,continuous-wave laser,transparent ceramic
更新于2025-09-19 17:13:59
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Microstructure control, competitive growth and precipitation rule in faceted Al2O3/Er3Al5O12 eutectic in situ composite ceramics prepared by laser floating zone melting
摘要： Microstructure control and competitive growth of Al2O3/Er3Al5O12 eutectic/off-eutectics are explored over wide ranges of solidification rates and compositions. Gradual transformation phenomenon of microstructure morphology from complete eutectic to eutectic + coarse Er3Al5O12 phase and to eutectic + Er3Al5O12 dendrite is observed and the corresponding influence factors are evaluated. Competitive growth between single-phase Al2O3 (or Er3Al5O12) dendrite and eutectic is analyzed and coupled growth zone is mapped through comparing interface temperatures of different patterns of microstructures. The complete eutectic microstructure could be obtained at Al2O3/Er3Al5O12 hypoeutectic (Al2O3-17.5 mol% Er2O3) under fast solidification rate and the onset growth rate (~0.94 × 104 μm/s) estimated from the measured eutectic spacing (~150 nm) fits well with the result calculated on the basis of competitive growth (~1.27 × 104 μm/s). Transformation of microstructure from irregular eutectic to regular eutectic and probable adjustment mechanism of eutectic spacings are discussed when the eutectic spacings refined from micron-scale (< 10 μm) to nano-scale (~20 nm).
关键词： Competitive growth,Directional solidification,Microstructure control,Precipitation rule,Oxide ceramic
更新于2025-09-19 17:13:59
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Eu2+ and Mn2+ co-doped oxyfluoride glass ceramic for white color conversion of 400??nm UV-LED
摘要： SiO2–Na2O–Al2O3–LaF3 glasses doped with Eu2t and Mn2t were synthesized to fabricate an inorganic color converter for white LED. When Eu2t was formed within the glass matrix, the obtained glasses showed cyan emission under 400 nm excitation upon heat treatment and the emission peak has been shifted with the crystallization. White emission has been successfully achieved with the introduction of Mn2t which supplemented red emission. The glass ceramic has been mounted on a 400 nm UV-LED and successfully demonstrated its practical feasibility with color rendering index of 91.3. The effect of heat treatment and energy transfer between Eu2t and Mn2t has been discussed.
关键词： Mn2t,Eu2t,Oxyfluoride,Glass ceramic,LED
更新于2025-09-19 17:13:59
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Recorded color rendering index in single Ce,(Pr,Mn):YAG transparent ceramics for high-power white LEDs/LDs
摘要： Transparent ceramic (TC) is an incredibly promising color converter for high-power white LEDs/LDs. However, the preparation process of multiple structured TC with high color rendering index (CRI) is complicated and of technical challenge, and the inability of a single structured TC to achieve a high CRI significantly limits its real application. In this study, high quality single structured Ce,(Pr,Mn):YAG TCs with the 'wide peak' and 'narrow peak' red light emission were designed and fabricated by the solid-state reaction and vacuum sintering method. Compared with the emission spectra of the Ce:YAG TC, synchronous doping Pr3+ and Mn2+ ions into Ce:YAG TCs resulted in an inhomogeneous broaden of the full width at half maximum (FWHM) from 91.7 nm to 102.2 nm. Impressively, the CRI of the single Ce,(Pr,Mn):YAG TC based high-power white LEDs was as high as 84.8, and the correlated-color temperature (CCT) of the white LEDs/LDs were 5450 K and 3550 K, respectively. Furthermore, when the addition amounts of Pr3+ and Mn2+ were 0.2 at.% and 0.8 at.%, respectively, the prepared Ce,(Pr,Mn):YAG TC displayed a high quantum efficiency (IQE=48.14%) and an excellent color stability (only 5% fluctuation). Therefore, this work not only shows how to overcome the spectrum deficiencies of single structured TCs that restrains the intrinsic CRI improvement, but also provides a reference for the pursuit of a high luminescent property. It significantly reinforces the understanding of CRI problems of TC based high-power lighting, which is crucial for the real application of white LEDs/LDs.
关键词： color rendering index,Ce,(Pr,Mn):YAG,synchronous doping,high-power white LEDs/LDs,Transparent ceramic
更新于2025-09-19 17:13:59
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Performance analysis of laser-induced biomimetic ceramic tools in interrupted cutting
摘要： Theoretical and experimental researches were conducted to analyze the performance of laser-induced biomimetic ceramic tools in interrupted cutting. The formation of biomimetic microscopic structure and its effects on the tool load and the mechanical behaviors were integrated in tool performance analysis. This work investigated the influences of the laser pulse angle and number on the ablation of the ceramic. A two-dimensional microstructure model was utilized when investigating the influences. The distribution variation of the heat source intensity was considered in the analysis of the influences. Fractal theory, damage mechanics and fracture mechanics were employed to analyze the mechanical behaviors for the biomimetic ceramic. These mechanical behaviors included the fractal dimension corresponding to the microcrack caused by laser, the initial integrated damage and the fracture toughness. A performance indicator was established for the biomimetic ceramic tool considering the tool load and the mechanical behaviors. It was found that the maximum depth caused by the laser pulses can be used to mirror the mechanical behaviors. The fractal dimension had a potential for the effective evaluation of the initial integrated damage and the fracture toughness. When the laser angle was 60° and the number of scans was 3, the biomimetic ceramic tool exhibited the best performance. The balance among the tool load, the initial integrated damage and the fracture toughness should be achieved to obtain the best tool performance.
关键词： Ceramic ablation,Mechanical behavior,Cutting performance,Biomimetic ceramic tool
更新于2025-09-16 10:30:52
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An Image-Based Gamut Analysis of Translucent Digital Ceramic Prints for Coloured Photovoltaic Modules
摘要： Colouring the frontglass of photovoltaic (PV) modules via digital ceramic printing aids in concealing the PV modules when integrated into existing building fa?ades as building-integrated photovoltaics (BIPV), while admitting sufficient light to produce electricity. This promotes the visual acceptance and adoption of PV modules as a source of renewable energy in urban environments. The effective colour of the PV laminate is a combination of the transparent colour on glass and the colour of the PV cells. This colour should ideally match the architect’s visual expectations in terms of fidelity, but also in terms of relative PV efficiency as a function of print density. In practice, these requirements are often contradictory, particularly for vivid colours, and the visual results may deviate significantly. This paper presents an objective analysis of how colours appear on ceramically printed frontglass when laminated with a PV module, using an image-based colour acquisition process. Given a set of 1044 nominal colours uniformly distributed in the RGB colour space, each printed in 10 opacities, we quantify the range of effective colours observed when printed on glass and combined with a PV module, and their deviation from the nominals. Our results confirm that the effective colour gamuts are significantly constrained and skewed, depending on the ink volume and glass finish used for printing. In particular, blue–magenta hues cannot be reliably rendered with this process. These insights can serve as guidelines for selecting target colours for BIPV that can be well approximated in practice.
关键词： colour gamut,colour difference,digital ceramic printing,building integrated photovoltaics
更新于2025-09-16 10:30:52
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Decoration Cylinder Pressure and it’s Influence on the Hue Variation of Ceramic Tiles Decorated by the Laser Engraving Silicone Cylinder Method
摘要： Several factors can influence the hue variation of tiles through contact elements; the pressure on the surface to be decorated is an important feature. This paper studied this variable applied to decoration by silicone cylinders. A variation of height was made between the cylinder and the tile. The influence of the feature is linked to cylinder wear and distance decrease. The reflectance, as well as the shape and filling of the decorated dots of gray scale values (5, 25 and 85%) were analyzed; the heights studied were 0.8; 1.0; 1.3 and 1.5mm. A similar behavior was observed in the engraving studied; in low shades of gray the reflectance decreases with increasing pressure and then becomes directly proportional; in the middle and high tones range the general trend was an increase in reflectance with increasing pressure on the ceramic tile.
关键词： ceramic tiles,hue variation,laser engraving,silicone cylinder
更新于2025-09-16 10:30:52