Search

A novel (Li,Cr)–ZrSiO 4 jade green ceramic pigment was prepared using LiF as the mineralizer and synergistically enhanced charge-compensator. The effects of Cr/Si mole ratio on the synthesis and coloration of the pigment and the coloring mechanism were investigated via XRD, SEM, TEM, XPS, EPR, NMR, UV–Vis–NIR and CIELAB colorimetry. The results demonstrate that the charge-compensator promotes the synthesis of ZrSiO 4 , and more Cr enters into the zircon lattice. When the n(Cr)/n(Si) is 0.2, the pigments exhibit a jade green hue (L* = 75.74, a* = -7.37, b* = 5.18). The band of the (Li,Cr)–ZrSiO 4 pigments in the visible light region shifts towards positive wavelength (535 nm), which is closer to the center of the green light region. The novel pigments have excellent coloring performance stability while in a base glaze synthesized at 1200 °C and near-infrared reflectance in the range of 700–2500 nm. The co-doping of lithium balances bonding, thereby improving near-infrared performance, which shows broad development prospects in the field of ceramic applications and energy saving. [ABSTRACT FROM AUTHOR]

Novel highly foldable HAp ceramic paper with fire retardancy but without fiber was fabricated via novel non-solvent displacement nonaqueous precipitation strategy. The obtained HAp ceramic paper, characterized by highly smooth and glossy, is characterized via X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), curlability test, moisture absorbency and Pb2+ removal performance test. The results show that the ceramic paper is very straight, uniform, and smooth with high curlability and low moisture absorption. No fiber is detected in the ceramic paper. No defect is either detected except for at the edge area. The HAp ceramic paper is grown along the (002) crystal plane of the hydroxyapatite phase from hexagonal plate like single crystal sheets. The ceramic paper loaded for four times has formed a clear four-layer-structured, with a total thickness of about 832 nm. The thickness of each layer is very uniform, with an average thickness of about 208 nm per layer. HAp ceramic paper has excellent Pb2+ ions removal performance, curling performance, moisture absorption performance and flame retardant performance. These performances confirm this novel HAp ceramic paper has superior properties over the traditional ceramic paper with fibers and shows great application prospect in various fields. [ABSTRACT FROM AUTHOR]

Novel HAp porous skeleton material with high pore homogeneity is prepared via nonaqueous precipitation method combined with medium-temperature induced intermolecular polycondensation. The obtained porous skeleton HAp material, which has characteristics of highly uniform hexagonal pore, is characterized via X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and Pb2+ removal performance test. The results show that the porous skeleton material presents with a highly uniform hexagonal pore. Both of the pore sizes and pore wall particles sizes have the average values of about 350 nm, with a different sizes range of 120–680 nm and 120–780 nm, respectively. HAp porous skeleton material has Pb2+ ions removal performance almost equivalent to that of nano porous sheets, because of its very uniform distribution of elements and three-dimensional structure caused by the uniform connection of the penetrating structure, group assembly, and intermolecular condensation. HAp porous skeleton material has much better separation performance and can effectively avoid problems of secondary pollution and difficulty for separation. HAp porous skeleton material is expected to be a novel excellent adsorbent for Pb 2+ ions purifying in industrial wastewater. [ABSTRACT FROM AUTHOR]

Effects of cores types on non-solvent displacement nonaqueous precipitation synthesis of core-shell structured materials were investigated via taking case study on effects of carbon sources on C@ZrSiO 4 preparation. The influencing mechanism of carbon sources was investigated via XRD, FE-SEM, TEM and the CIELAB colorimeter. The results show that the optimized carbon source for non-solvent displacement nonaqueous precipitation synthesis of C@ZrSiO 4 is amorphous and isolated spheroid-like carbon source. Neither layer-structured particle nor sheet-like particle can be effectively encapsulated through non-solvent displacement nonaqueous precipitation method. The shell layer is difficult to be effectively encapsulated on the edges of the around of corresponding particle. In comparison with the higher crystallinity core, the amorphous core is more favorable for encapsulation. The core materials selection principles discovered in this work are expected to be widely referred in the preparation of other core-shell structural materials. [ABSTRACT FROM AUTHOR]

A novel non-solvent displacement-nonaqueous precipitation method was developed for the preparation of core-shell materials by considering C@ZrSiO 4 black pigments synthesis as the case. The effects of the impregnation time, precursor concentration, and carbon content on the synthesis and coloration of the C@ZrSiO 4 pigment and the mechanism of this method were investigated via X-ray diffraction, transmission electron microscopy, field-emission scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and CIELAB colorimetry. The results showed that the optimal impregnation time, precursor concentration, and carbon content were 24 h, 1.5 mol/L, and 9 wt%, respectively. C@ZrSiO 4 -encapsulated pigments prepared by a non-solvent displacement-nonaqueous precipitation method have a uniform and dense shell-encapsulated zircon layer with a thickness of 10–20 nm. The size of C@ZrSiO 4 encapsulated pigments was 50–210 nm, without particle agglomeration. This uniform and dense encapsulation facilitated an excellent color-rendering effect in the high-temperature glaze, and the chromaticity values of the glaze were L* = 35.05, a* = 0.34, and b* = 1.08. The alkyl halide elimination non-hydrolytic heterocondensation reaction ensured the formation of a uniform precipitate along the surface of the carbon particles with Si–O–Zr bonds as the skeleton. The introduction of the non-solvent kerosene ensured the complete, uniform, and dense progress of the precipitation process to form a C@ZrSiO 4 pigment with a high-quality core-shell structure. The non-solvent displacement-nonaqueous precipitation method might be an extremely promising method for preparing core-shell structural materials. [ABSTRACT FROM AUTHOR]

This study explored the evolution of friction-induced vibration (FIV) and wear in high-speed train friction braking through experiments, theoretical analysis, and numerical simulation. Experimental tests revealed that vibration behavior transitions from high-frequency modes at high speeds to low-frequency stick-slip at lower speeds. Theoretical analysis indicated that brake disc speed, coefficient of friction (COF), and contact stiffness affect system stability. Specifically, the system experiences high-frequency vibrations at high speeds due to mode coupling, and the friction block surface primarily undergoes abrasive wear mechanisms. At lower speeds, the system demonstrates low-frequency stick-slip vibrations induced by the combined effects of mode coupling and negative friction velocity slope (NFVS) characteristics, and the friction block surface mainly experiences adhesive wear mechanisms. • FIV in high-speed train braking exhibits diverse mechanisms with speed changes. • The system stability is affected by brake disc speed, COF, and contact stiffness. • FIV is influenced by mode coupling and NFVS from high to low speeds. • The wear mechanism changes from abrasive to adhesive wear during deceleration. • FIV characteristics correlate with wear mechanisms on the friction block. [ABSTRACT FROM AUTHOR]