A type of ultra-light weighted, low-thermally conductive but mechanically strong ceramic foams (CF) were fabricated via the direct foaming method of using basalt tailings (BT) and black cotton soil (BCS) as main components. The sodium hydroxide (NaOH) dissolved in water glass (Na 2 SiO 3 ) and calcium carbonate (CaCO 3 ) were used as fluxing and foaming agents, respectively. The product was demonstrated to have excellent strength-to-density properties (compressive strength > 1.82 MPa, density < 0.57 g/cm 3 ) and a low thermal conductivity (0.057 W/m·K), which meets standards of ASTM C552-14 (Grade 24) or GB/T33500-2017 (Grade L). Factors that affect the physicochemical (bulk density, apparent density, and water absorption) and mechanical properties were investigated, which include dosages of BT, NaOH, and CaCO 3 . Optimum parameters were found as sintering temperature 850 °C, reaction time 45 min, and dosage of BT/(BT + BCS) = 70% wt., NaOH = 13% wt. versus the total weight of BT and BCS (w(BT + BCS)), and foaming agent CaCO 3 = 0.1% wt. versus w(BT + BCS). The crystalline phase in the foamed ceramics was confirmed as nepheline which was produced by desilication of orthoclase or plagioclase with presence of NaOH. This direct foaming method of using the BT + BCS system was proven to be an efficient way to prepare foamed ceramics.
Zhurong Mo,Yanping Huo,Haoyi Wu,Brij Mohan,Hongli Wen,Li Luo,Deshmukh Abdul Hakeem
We report the synthesis and the effect of synthesis temperature on the crystal structure and dual mode (DC/UC) luminescence properties of the NASE-1000–1300. Two different polymorphs, i.e., nepheline and carnegieite of the NASE have been prepared just by changing the annealing temperature. Multi wavelength excitation can be used to obtain different emissions in visible and NIR regions. Under 380 and 980 nm excitation, the NASE-1000–1300 produces 1535 nm NIR emission, whereas green and red visible emissions are observed with 980 and 808 nm laser excitations. Under 980 nm laser excitation, the synthesis temperature dependent nepheline and carnegieite polymorphs emit intense red and green emission, respectively. Two-photon process is responsible for the green and red UC emissions of the NASE-1300. The NASE-1000-1300 produces intense red emission under 808 nm laser excitation. We believe that the NASE-1000–1300 could be a promising candidate for the photonic as well as biological applications.
危险品化学品经营许可证（带存储）