The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Jianfeng Yang - One of the best experts on this subject based on the ideXlab platform.
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lithium disilicate glass ceramics by heat treatment of lithium Metasilicate glass ceramics obtained by hot pressing
Journal of the American Ceramic Society, 2015Co-Authors: Hui Zhang, Zhilong He, Yaming Zhang, Wenjia Jing, Bo Wang, Jianfeng YangAbstract:Lithium disilicate glass-ceramics are widely used as dental ceramics due to their machinability and translucency. In this study, lithium disilicate glass-ceramic was fabricated through heat treatment of lithium Metasilicate glass-ceramics obtained by hot pressing of glass powder composed of SiO2–Li2O–P2O5–ZrO2–Al2O3–K2O–CeO2 at low temperature. The crystalline phase, microstructure, and mechanical properties were investigated. The results indicated that lithium Metasilicate glass-ceramic with a relative density of higher than 99% was obtained after hot pressing, and glass-ceramic with interlocked rod-like Li2Si2O5 crystals and good flexural strength (338 ± 20 MPa) was successfully obtained through heat treatment. The two-step method was believed to be feasible in tailoring the microstructure and mechanical properties of lithium disilicate glass-ceramics.
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Lithium Disilicate Glass‐Ceramics by Heat Treatment of Lithium Metasilicate Glass‐Ceramics Obtained by Hot Pressing
Journal of the American Ceramic Society, 2015Co-Authors: Hui Zhang, Zhilong He, Yaming Zhang, Wenjia Jing, Bo Wang, Jianfeng YangAbstract:Lithium disilicate glass-ceramics are widely used as dental ceramics due to their machinability and translucency. In this study, lithium disilicate glass-ceramic was fabricated through heat treatment of lithium Metasilicate glass-ceramics obtained by hot pressing of glass powder composed of SiO2–Li2O–P2O5–ZrO2–Al2O3–K2O–CeO2 at low temperature. The crystalline phase, microstructure, and mechanical properties were investigated. The results indicated that lithium Metasilicate glass-ceramic with a relative density of higher than 99% was obtained after hot pressing, and glass-ceramic with interlocked rod-like Li2Si2O5 crystals and good flexural strength (338 ± 20 MPa) was successfully obtained through heat treatment. The two-step method was believed to be feasible in tailoring the microstructure and mechanical properties of lithium disilicate glass-ceramics.
R M Souto - One of the best experts on this subject based on the ideXlab platform.
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evaluation of the corrosion protection of steel by anodic processing in Metasilicate solution using the scanning vibrating electrode technique
Electrochimica Acta, 2015Co-Authors: Javier Izquierdo, B M Fernandezperez, L Martinruiz, V Mena, Raquel Rodriguezraposo, J J Santana, R M SoutoAbstract:Abstract Anodic processing in Metasilicate solution was investigated for the improvement of the corrosion resistance of various steels, namely F111 low alloy carbon and 304 stainless steels, as well as on galvanized steel cut edges. The efficiency of the prior electrochemical treatment for each material was tested during their exposure to naturally-aerated aqueous chloride solutions of different aggressiveness. Analysis was performed using the scanning vibrating electrode technique (SVET) in order to detect local ionic current distributions over the samples under study associated to the corrosion reactions. The onset of corrosion processes was greatly inhibited after anodic processing with Metasilicate on both the low alloy carbon steel and the galvanized steel cut edge. Conversely, SVET analysis of unbiased 304 steel samples tested in 0.1 M chloride-containing solution did not show differences between pristine and Metasilicate-treated surfaces. Differences in the electrochemical reactivity between treated and non-treated 304 steel surfaces were only observed after partial removal of the corresponding passive layers under operator-controlled polarization.
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improvement in pitting resistance of stainless steel surfaces by prior anodic treatment in Metasilicate solution
Journal of The Electrochemical Society, 2004Co-Authors: G T Burstein, R M SoutoAbstract:Departamento de Qui´mica Fi´sica, Universidad de La Laguna, Tenerife, SpainMild anodizing treatment of 304 stainless steel microelectrodes in sodium Metasilicate solution reduces the frequency of pitnucleation events markedly when the metal is subsequently exposed to acidic chloride solutions. The same treatment of largerspecimens increases the pitting potential substantially. The results confirm that the frequency and/or amplitude of the currentspikes that nucleate pitting corrosion on an ultramicroscopic scale have a strong bearing on the pitting characteristics of the metal.Identical surface treatment, but in hydroxide solution of pH similar to the Metasilicate solution, yields a much smaller improve-ment in pitting characteristics, as demonstrated by both analysis of the pit nucleation events on microelectrodes as well as thepitting potential. The effect of the Metasilicate treatment is due to a specific action of the Metasilicate anion with the pit nucleationsites. The effect on the overall passive state is marginal. It is proposed that the Metasilicate treatment effectively caps the pitnucleation sites by forming a silicate- or silica-rich coating over those sites, a process we term ‘‘electrochemical pit site capping.’’© 2004 The Electrochemical Society. @DOI: 10.1149/1.1787172# All rights reserved.Manuscript submitted November 11, 2003; revised manuscript received February 25, 2004. Available electronically September 1,2004.
Hui Zhang - One of the best experts on this subject based on the ideXlab platform.
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lithium disilicate glass ceramics by heat treatment of lithium Metasilicate glass ceramics obtained by hot pressing
Journal of the American Ceramic Society, 2015Co-Authors: Hui Zhang, Zhilong He, Yaming Zhang, Wenjia Jing, Bo Wang, Jianfeng YangAbstract:Lithium disilicate glass-ceramics are widely used as dental ceramics due to their machinability and translucency. In this study, lithium disilicate glass-ceramic was fabricated through heat treatment of lithium Metasilicate glass-ceramics obtained by hot pressing of glass powder composed of SiO2–Li2O–P2O5–ZrO2–Al2O3–K2O–CeO2 at low temperature. The crystalline phase, microstructure, and mechanical properties were investigated. The results indicated that lithium Metasilicate glass-ceramic with a relative density of higher than 99% was obtained after hot pressing, and glass-ceramic with interlocked rod-like Li2Si2O5 crystals and good flexural strength (338 ± 20 MPa) was successfully obtained through heat treatment. The two-step method was believed to be feasible in tailoring the microstructure and mechanical properties of lithium disilicate glass-ceramics.
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Lithium Disilicate Glass‐Ceramics by Heat Treatment of Lithium Metasilicate Glass‐Ceramics Obtained by Hot Pressing
Journal of the American Ceramic Society, 2015Co-Authors: Hui Zhang, Zhilong He, Yaming Zhang, Wenjia Jing, Bo Wang, Jianfeng YangAbstract:Lithium disilicate glass-ceramics are widely used as dental ceramics due to their machinability and translucency. In this study, lithium disilicate glass-ceramic was fabricated through heat treatment of lithium Metasilicate glass-ceramics obtained by hot pressing of glass powder composed of SiO2–Li2O–P2O5–ZrO2–Al2O3–K2O–CeO2 at low temperature. The crystalline phase, microstructure, and mechanical properties were investigated. The results indicated that lithium Metasilicate glass-ceramic with a relative density of higher than 99% was obtained after hot pressing, and glass-ceramic with interlocked rod-like Li2Si2O5 crystals and good flexural strength (338 ± 20 MPa) was successfully obtained through heat treatment. The two-step method was believed to be feasible in tailoring the microstructure and mechanical properties of lithium disilicate glass-ceramics.
Yibiao Xu - One of the best experts on this subject based on the ideXlab platform.
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hydration evolution of mgo sio2 slurries in the presence of sodium Metasilicate
Ceramics International, 2018Co-Authors: Yu Zhang, Yawei Li, Yibiao XuAbstract:Abstract In order to accelerate the formation of magnesium-silicate-hydrate gel (M-S-H), the sodium Metasilicate was added into the MgO-SiO 2 slurries. The effect of sodium Metasilicate on the hydration process of MgO-SiO 2 slurries was investigated in this work. It required a relatively small amount of sodium Metasilicate to facilitate the formation of M-S-H and to surpress the brucite formation. In the early 24 h, the M-S-H formed quickly due to the high concentration of magnesium ions and silicate species in solutions. With the further increasing of curing time, the M-S-H gel phase continuously grew. Furthermore, the sufficient silicate ions amount was favorable for the transformation of newly formed brucite to the M-S-H phase. The addition of sodium Metasilicate influenced not only the reaction process but also the morphology of hydrates. Instead of the yolk-shell structure, the flower-like and stacked sheet-like M-S-H formed in the presence of sodium Metasilicate.
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enhanced formation of magnesium silica hydrates m s h using sodium Metasilicate and caustic magnesia in magnesia castables
Ceramics International, 2017Co-Authors: Yu Zhang, Yawei Li, Yibiao Xu, Shaobai SangAbstract:Abstract Magnesium-silica-hydrates (M-S-H) is a promising binder for magnesia castables due to its bonding strength and progressive dehydration behavior over a wide temperature range during the heating-up stage. Sodium Metasilicate and caustic magnesia were used to form M-S-H in magnesia castables. The results showed that M-S-H was remarkably produced in the caustic magnesia-microsilica slurries containing sodium Metasilicate with increasing pH value, which activated the hydrolysis of microsilica into silicic ions and enhanced the M-S-H formation. When 0.3 wt% caustic magnesia and 0.05 wt% sodium Metasilicate as additives were incorporated into magnesia castables, the cold crushing strength and cold modulus of rupture of castables after drying at 110 °C reached the maximum value of 68.3 MPa, which corresponded to ~ 40% improvement in comparison with those of caustic magnesia and sodium Metasilicate-free magnesia castables. Besides, the enhanced formation of M-S-H bonding system contributed to a better explosion resistance of magnesia castables.
Yasutake Ohishi - One of the best experts on this subject based on the ideXlab platform.
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optical properties of cr3 ion in lithium Metasilicate li2o sio2 transparent glass ceramics
Journal of Non-crystalline Solids, 2008Co-Authors: Shigeki Morimoto, Sasithorn Khonthon, Yasutake OhishiAbstract:Abstract The optical properties of Cr3+ ions in lithium Metasilicate (Li2O · SiO2) transparent glass–ceramics were investigated. The main crystalline phase precipitated was the lithium Metasilicate (Li2O · SiO2) crystal. The percent crystallinity and crystalline size were ranging 65–75% and 20–35 nm, respectively. The color changes drastically to deep pink from emerald green upon crystallization. New and strong absorption bands appeared and the absorption intensity increases by about 10 times that in glass. These new absorption bands are found to be derived from Cr3+ ions in octahedral sites in the lithium Metasilicate crystal lattice. Cr3+ ions substitute for three Li+ ions and occupy the distorted octahedral site between single [SiO4]n chains of lithium Metasilicate crystal. The ligand field parameters can be estimated: 10Dq = 13 088 cm−1, B = 453 cm−1, Dq/B = 2.89 and C = 2036 cm−1. The near-infrared luminescence centered at 1250 nm was not detected in the deep pink glass–ceramics unlike emerald green glass.
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Optical properties of Cr3+ ion in lithium Metasilicate Li2O · SiO2 transparent glass–ceramics
Journal of Non-crystalline Solids, 2008Co-Authors: Shigeki Morimoto, Sasithorn Khonthon, Yasutake OhishiAbstract:Abstract The optical properties of Cr3+ ions in lithium Metasilicate (Li2O · SiO2) transparent glass–ceramics were investigated. The main crystalline phase precipitated was the lithium Metasilicate (Li2O · SiO2) crystal. The percent crystallinity and crystalline size were ranging 65–75% and 20–35 nm, respectively. The color changes drastically to deep pink from emerald green upon crystallization. New and strong absorption bands appeared and the absorption intensity increases by about 10 times that in glass. These new absorption bands are found to be derived from Cr3+ ions in octahedral sites in the lithium Metasilicate crystal lattice. Cr3+ ions substitute for three Li+ ions and occupy the distorted octahedral site between single [SiO4]n chains of lithium Metasilicate crystal. The ligand field parameters can be estimated: 10Dq = 13 088 cm−1, B = 453 cm−1, Dq/B = 2.89 and C = 2036 cm−1. The near-infrared luminescence centered at 1250 nm was not detected in the deep pink glass–ceramics unlike emerald green glass.