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The present study aims to clarify the role of ball pitch in Al 2 O 3 –SiC–C (ASC) refractory castables and investigate the influence of low temperature treatment on the composition, microstructural evolution, and properties of ASC refractory castables. By utilizing the expansion properties of ball pitch during heating, the castables undergo a low temperature treatment to induce the flow and expansion of ball pitch within the castables. This, in turn, fills the surrounding pores and enhances the physical properties of the castables. The results of this study demonstrate that low-temperature heat treatment of the castables at temperatures at 350 °C significantly improves the hot modulus of rupture, oxidation resistance, and slag resistance after sintering. This improvement is attributed to the optimized microstructure. In comparison to the corresponding samples without low temperature treatment, the high temperature modulus of rupture (HMOR) of the calcined castables treated at 350 °C increases by 33.3%. Additionally, the oxidation index and slag corrosion index after sintering at 1500 °C decrease by 39.6% and 87.31% respectively for the samples low temperature treated at 350 °C, as compared to the samples low temperature treated at 110 °C. This study provides a fresh perspective on the production of ASC castables with exceptional high temperature performance. [ABSTRACT FROM AUTHOR]

We report a facile method to enhance the photoluminescence of 6Y–ZrO 2 : Er3+ translucent ceramics prepared via the vacuum sintering technique by introducing Ag. Ag atoms could be incorporated into the host at high temperatures; these atoms partially precipitated to form Ag nanoparticles during cooling. The intensities of green up-conversion, 1.5 and 2.7 μm emissions under 980 nm excitation, and the green down-conversion luminescence upon 377 nm excitation were improved via co-doping with Ag due to the modification of the local crystal field and the surface plasmon resonance effect. Based on the fluorescence intensity ratio of 2H 11/2 → 4I 15/2 versus 4S 3/2 → 4I 15/2 , 6Y–ZrO 2 : 1 mol%Er3+, 0.67 μmol%Ag exhibited the maximal relative sensing sensitivity of 1.12 %K−1, which could be applied as a potential thermometer with good sensitivity. The present work sheds light on how to simultaneously enhance the emission intensity and thermal sensitivity of Er3+ in ceramics. [ABSTRACT FROM AUTHOR]

In the present work, the influence of low-cost self-synthesized Al 2 O 3 – B 2 O 3 composite bubble on the oxidation resistance and mechanical properties of Al 2 O 3 –SiC–C (ASC) castables were investigated. The pre-fabricated composite bubble were characterized in detail. The properties of the ASC castables were measured, including their oxidation indexes, ambient and high-temperature mechanical properties, and microstructural evaluations. The results showed that the introduction of moderate contents of Al 2 O 3 – B 2 O 3 composite bubble effectively improved the oxidation resistance and mechanical properties of the ASC castables by volumetric expansion, improved powder filling performance, and the in-situ formation of a high-strength whisker network in the high-temperature flowing liquid phase. These results demonstrated the dual-functional application of Al 2 O 3 – B 2 O 3 composite bubble in ASC castables as antioxidants and mechanical reinforcements simultaneously. [ABSTRACT FROM AUTHOR]

Outdoor lighting and other lighting systems can disrupt natural plant growth habits. Thus, LED lighting that is not detrimental to plant growth is required. In our study, Dy3+-doped Ca 8 ZnY(PO 4) 7 :Dy3+ phosphor with enhanced luminescence properties caused by the co-dopants Mg2+ and B3+ were synthesised. The samples had multiple excitation peaks, indicating they are excited by either near-ultraviolet (n-UV) or blue chips. All samples exhibited bright narrow yellow and blue emission corresponding to the transitions of Dy3+ ions with 4F 9/2 →6H 13/2 and 4F 9/2 →6H 13/2 , respectively. Moreover, doping with Mg2+ and B3+ enhanced the luminescence intensity, reaching 113.6 and 119.7%, respectively. In addition, the luminescence emission intensity at 150 °C was maintained at approximately 95% of the initial value at 25 °C, and its thermal stability increased by 123%. Devices assembled with an n-UV chip (388 nm) and the as-obtained CZMYP:Dy3+ phosphor emitted a bright warm white light and simulated outdoor dark lighting for tobacco cultivation, indicating that the as-prepared phosphor is an excellent candidate material for plant habitat-conscious phosphors. [ABSTRACT FROM AUTHOR]

Abstract Mullite castables are widely used in hot metal pretreatment processing equipment. In this work, the effects of alumina bubble particle size on the microstructure and physical properties of mullite castables were studied. Grey relational analysis is a useful method for analyzing patterns in multivariate cases. In this paper, the grey relational analysis was used to estimate the relationship between the properties of samples and the structure of alumina bubbles. Using grey analysis, the specific surface area of alumina bubbles was determined to have the greatest influence on the properties of apparent porosity, cold mechanical properties and thermal shock resistance. The hollow radius of alumina bubbles has the greatest relationship to bulk density, hot modulus of rupture, flow values and coefficient of thermal expansion of samples. Finally, the mullite castables with a high modulus of rupture and thermal shock resistance was obtained by adding alumina bubbles with a particle size between 0.5 and 1 mm. The high modulus of rupture was shown to be caused by the alumina bubble spherical shape, hollow structure and the appropriate bonding at the alumina bubble/matrix interface. [ABSTRACT FROM AUTHOR]

The efficient optimisation of radiation shielding materials (RSMs), which protect people from potential radiant threats, is highly desirable; however, it remains challenging. This study addresses the low-cost fabrication of the ceramic-based RSMs, aluminium borate-based ceramics using Bi 2 O 3 as a novel simultaneous shielding agent and sintering promoter. The phase compositions, microstructures, sintering kinetics, and performances of the as-prepared Bi 2 O 3 doped aluminium borate ceramics (BDABCs) are systematically researched. Finally, co-shielding tests for neutron and gamma radiation are performed. The results demonstrate that Bi 2 O 3 can positively influence the sintering densification process of BDABCs via the evident reduction in the sintering activation energy. The migration of the Bi 2 O 3 –B 2 O 3 liquid phase affects the pore structure, crystal morphology, and thermal conductivity of the samples. The obtained BDABCs exhibited highly reliable mechanical properties with a maximum elastic modulus and modulus of rupture of 124.3 GPa and 54.9 MPa, respectively; controllable thermal conductivity from 1.32 to 6.16 W m−1 K−1; and 12 wt% Bi 2 O 3 -doped sample (1400 °C × 3 h, 1.5 cm) shows the best radiation shielding performance, including 58.6% neutron and 26.6% γ rays. The obtained results manifest the enormous potential of BDABCs as structural materials and functional RSMs. [ABSTRACT FROM AUTHOR]

A novel fabrication method for reticulated porous ceramics (RPCs) with high strength and high porosity has been proposed based on polymeric replica method and in-situ synthesis of mullite whiskers. Through the FactSage theoretical prediction, the mullite was produced in A10, A15 and A20 coating slurries and the liquid phase viscosity was decreased with increasing sintering temperature and AlF 3 content. The results show that as the AlF 3 content in coating slurry increases, the amount of mullite phase increases and the internal pore structure of the struts in the RPCs changed from triangular to rounded. Adding appropriate AlF 3 content in the coating slurry facilitated the growth of mullite whiskers, but excessive AlF 3 content caused the formation of amorphous crystals. The method used here improved the compressive strength without significantly reducing the porosity. Compared to untreated specimens, the compressive strength and residual strength ratio of sample A15 were increased by 38.24% and 19.75%. [ABSTRACT FROM AUTHOR]