The fundamental science behind glass and glass-ceramics in relation to research including syntheses, processing, characterization and applications are critically reviewed in this paper. The crystalline structure of th...The fundamental science behind glass and glass-ceramics in relation to research including syntheses, processing, characterization and applications are critically reviewed in this paper. The crystalline structure of the crystalline phases/s investigated in the literature is also discussed. Throughout this paper, the scene is set toward the overall picture of the rationale behind the choice of a glass system. Additionally, earlier reviews do not include the most recent literature in this fast-moving field. The main methods of synthesizing glasses and glass-ceramics are explained and described in relation to their applications. The paper concludes with recommendations for future research.展开更多
Using differential thermal analysis, X-ray phase analysis, electron microscopy, and optical microscopy, the nucleation of crystals in glass obtained by blending metallurgical slag with silicon dioxide has been studied...Using differential thermal analysis, X-ray phase analysis, electron microscopy, and optical microscopy, the nucleation of crystals in glass obtained by blending metallurgical slag with silicon dioxide has been studied. The type of crystallization (homogeneous or heterogeneous, volume or surface) is revealed for each of nine compositions of synthesized glass. It is shown that the first crystalline phase in a volume crystallizing glass is perovskite (CaO·TiO2);in this phase a nucleation of the main phase occurs: melilite (solid solution of gehlenite 2CaO·Al2O3·SiO2 in akermanite 2CaO·MgO·2SiO2). The fundamental characteristics of homogeneous (for a catalizing phase, perovskite) and heterogeneous (for a catalyzed phase, melilite) of crystallization are determined: the steady state nucleation rate Ist, time of unsteady state nucleation τ, crystal growth rate U, and activation energy of frictional flow. The temperature dependences of Ist, τ, and U are obtained. The kinetics of the crystallization of glass is studied and the rates of the surface crystal growth are determined in the glass of nine compositions. The influence of grinding the particles of the original glass on the sequence of deposition of the crystalline phases was studied. Practical recommendations are presented for the use of blast-furnace slag as a raw material for the synthesis of glass and their further utilization.展开更多
Foamed glass-ceramics were prepared via a single-step sintering method using high-titanium blast furnace slag and waste glass as the main raw materials The influence of sintering temperature(900–1060℃) on the micros...Foamed glass-ceramics were prepared via a single-step sintering method using high-titanium blast furnace slag and waste glass as the main raw materials The influence of sintering temperature(900–1060℃) on the microstructure and properties of foamed glass-ceramics was studied. The results show that the crystal shape changed from grainy to rod-shaped and finally turned to multiple shapes as the sintering temperature was increased from 900 to 1060℃. With increasing sintering temperature, the average pore size of the foamed glass-ceramics increased and subsequently decreased. By contrast, the compressive strength and the bulk density decreased and subsequently increased. An excessively high temperature, however, induced the coalescence of pores and decreased the compressive strength. The optimal properties, including the highest compressive strength(16.64 MPa) among the investigated samples and a relatively low bulk density(0.83 g/cm^3), were attained in the case of the foamed glass-ceramics sintered at 1000℃.展开更多
The crystallization kinetics of 38.0CaO-38.0Al2O3-10.5BaO-6.5MgO-6.0Y2O3-1.0（Na2O＋K2O） （wt%） glass was studied by differential scanning calorimeter （DSC） and X-ray diffraction （XRD） techniques. Tile results s...The crystallization kinetics of 38.0CaO-38.0Al2O3-10.5BaO-6.5MgO-6.0Y2O3-1.0（Na2O＋K2O） （wt%） glass was studied by differential scanning calorimeter （DSC） and X-ray diffraction （XRD） techniques. Tile results showed that DSC curves of calcium aluminate glass have a single glass transition temperature followed by one crystallization peak for the heating rates β = 5 K/min and two crystallization temperatures T1 and T2 for β≥ 10 K/min. The activation energies of crystallization obtained from the Gao-Wang model of the first exothermal peak and the second exothermal peak of calcium aluminate glass are 340 and 662 kJ/mol, respectively. The Avrami exponents of the both crystallization peaks are approximately 2, indicating the two- dimensional crystalline growth during its transformation from amorphous to crystalline. Ca12Al14O33, Ca3Al2O6 and unknown crystalline phases firstly appear when calcium aluminate glass is heat-treated. With the extending of heat-treatment duration, BaAl2O4 phase comes out.展开更多
文摘The fundamental science behind glass and glass-ceramics in relation to research including syntheses, processing, characterization and applications are critically reviewed in this paper. The crystalline structure of the crystalline phases/s investigated in the literature is also discussed. Throughout this paper, the scene is set toward the overall picture of the rationale behind the choice of a glass system. Additionally, earlier reviews do not include the most recent literature in this fast-moving field. The main methods of synthesizing glasses and glass-ceramics are explained and described in relation to their applications. The paper concludes with recommendations for future research.
文摘Using differential thermal analysis, X-ray phase analysis, electron microscopy, and optical microscopy, the nucleation of crystals in glass obtained by blending metallurgical slag with silicon dioxide has been studied. The type of crystallization (homogeneous or heterogeneous, volume or surface) is revealed for each of nine compositions of synthesized glass. It is shown that the first crystalline phase in a volume crystallizing glass is perovskite (CaO·TiO2);in this phase a nucleation of the main phase occurs: melilite (solid solution of gehlenite 2CaO·Al2O3·SiO2 in akermanite 2CaO·MgO·2SiO2). The fundamental characteristics of homogeneous (for a catalizing phase, perovskite) and heterogeneous (for a catalyzed phase, melilite) of crystallization are determined: the steady state nucleation rate Ist, time of unsteady state nucleation τ, crystal growth rate U, and activation energy of frictional flow. The temperature dependences of Ist, τ, and U are obtained. The kinetics of the crystallization of glass is studied and the rates of the surface crystal growth are determined in the glass of nine compositions. The influence of grinding the particles of the original glass on the sequence of deposition of the crystalline phases was studied. Practical recommendations are presented for the use of blast-furnace slag as a raw material for the synthesis of glass and their further utilization.
基金financially supported by the Science and Technology Support Program of Sichuan Province (No.2014GZ0011)the Industry Promotion Project of Panzhihua City, China (No.2012CY-C-2)
文摘Foamed glass-ceramics were prepared via a single-step sintering method using high-titanium blast furnace slag and waste glass as the main raw materials The influence of sintering temperature(900–1060℃) on the microstructure and properties of foamed glass-ceramics was studied. The results show that the crystal shape changed from grainy to rod-shaped and finally turned to multiple shapes as the sintering temperature was increased from 900 to 1060℃. With increasing sintering temperature, the average pore size of the foamed glass-ceramics increased and subsequently decreased. By contrast, the compressive strength and the bulk density decreased and subsequently increased. An excessively high temperature, however, induced the coalescence of pores and decreased the compressive strength. The optimal properties, including the highest compressive strength(16.64 MPa) among the investigated samples and a relatively low bulk density(0.83 g/cm^3), were attained in the case of the foamed glass-ceramics sintered at 1000℃.
基金Funded by the National Natural Science Foundation of China(No.60808024)
文摘The crystallization kinetics of 38.0CaO-38.0Al2O3-10.5BaO-6.5MgO-6.0Y2O3-1.0（Na2O＋K2O） （wt%） glass was studied by differential scanning calorimeter （DSC） and X-ray diffraction （XRD） techniques. Tile results showed that DSC curves of calcium aluminate glass have a single glass transition temperature followed by one crystallization peak for the heating rates β = 5 K/min and two crystallization temperatures T1 and T2 for β≥ 10 K/min. The activation energies of crystallization obtained from the Gao-Wang model of the first exothermal peak and the second exothermal peak of calcium aluminate glass are 340 and 662 kJ/mol, respectively. The Avrami exponents of the both crystallization peaks are approximately 2, indicating the two- dimensional crystalline growth during its transformation from amorphous to crystalline. Ca12Al14O33, Ca3Al2O6 and unknown crystalline phases firstly appear when calcium aluminate glass is heat-treated. With the extending of heat-treatment duration, BaAl2O4 phase comes out.
