2 edition of Non-isothermal calorimetric studies of the crystallization of lithium disilicate glass found in the catalog.
Non-isothermal calorimetric studies of the crystallization of lithium disilicate glass
|Statement||C.S. Ray ... [et al.].|
|Series||[NASA contractor report] -- 207363., NASA contractor report -- NASA CR-207363.|
|Contributions||Ray, C. S., United States. National Aeronautics and Space Administration.|
|The Physical Object|
SiO 2-Li 2 O-K 2 O-Al 2 O 3-P 2 O 5 based lithium disilicate glass ceramic was prepared and fabricated into dental crowns. The influence of factors such as pre-crystallization temperature and fabrication technique on the phase formation and morphology of the glass Author: Naruporn Monmaturapoj, Autcharaporn Sri-On, Thossapol Chunkiri. The result revealed that the GeO 2 /SiO 2 replacement in lithium disilicate glass-ceramic increased the density value of the prepared crystalline sample from to g/cm 3. Non-isothermal calorimetric studies of the crystallization of lithium disilicate glass. J Non-Cryst Solids, (), pp. Cited by: 2.
Nucleation rates and crystal growth velocities of the glass Nb In a recently published pa 1 or 2 mol% Nb 2 O 5 or Ta 2 O 5 were added to stoichiometric lithium disilicate glass Cited by: This work proposes three different glass formula derived from the SiO2-Li2O-K2O-Al2O3 system to investigate the effect of glass compositions on their crystal formation and mechanical properties. Glass LD_1 was SiO2-Li2O-K2O-Al2O3 system with adding P2O5 and CaF2 as nucleating agents. In Glass LD_2, a few amount of MgO was mixed to improve the viscosity of the : Naruporn Monmaturapoj, Pornchanok Lawita, Witoon Thepsuwan.
The phase evolution of a high flexural strength lithium disilicate (Li2Si2O5: LS2) glass-ceramic in a complex SiO2–Li2O–Al2O3–MgO–P2O5–ZrO2 glass system has been investigated as a function of temperature using in situ and ex situ X-ray diffraction (XRD) and 31P and 29Si solid-state nuclear magnetic resonance (SSNMR) by: 6. The aim of this study is to quantify the effect of the crystallization process on lithium disilicate ceramic crowns fabricated using a computer-aided design/computer-aided manufacturing (CAD/CAM) system and to determine whether the effect of crystallization is clinically acceptable by comparing values of fit before and after the crystallization by: 8.
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ELSEVIER Journal of Non-Crystalline Solids () ]OURNALOF Non-isothermal calorimetric studies of the crystallization of lithium disilicate glass C.S. Ray a, D.E. Day a, W. Huang a, K. Lakshmi Narayan K.F. Kelton b., b, T.S. Cull b, a Graduate Center for Materials Research, Uniuersity ofMissouri-Rolla, Rolla, MOUSA b Department of Phystcs, Cited by: Get this from a library.
Non-isothermal calorimetric studies of the crystallization of lithium disilicate glass. [C S Ray; United States. National Aeronautics and Space Administration.;]. Here, we present results obtained from non-iso- thermal DTA studies of lithium disilicate glass, which is known to crystallize polymorphically by homoge- neous nucleation.
A method for probing the tempera- ture range for significant nucleation is presented and critiqued. Based on DTA and microscopy experiments, we show that small particles of lithium disilicate glasses crystallize primarily by surface crystallization.
The relative importance of surface versus volume crystallization is examined by varying particle size, by introducing nucleating agents and by exposing glasses to atmospheres of different water by: Ray CS, Day DE, Huang W, Narayan KL, Cull TC, Kelton KF.
Non-isothermal calorimetric studies of the crystallization of lithium disilicate glass. J Non-Cryst Solids. ;– Article; Google ScholarCited by: 7. Kelton, " Non-Isothermal Calorimetric Studies of the Crystallization of Lithium Disilicate Glass, " J.
Non-Cryst. Solids,1–12 (). In this study, a rapid and simple calculation procedure to determine the non-isothermal crystallization kinetic parameters of a glass was proposed based on the work of Matusita et al. The crystal growth index (n) was firstly determined with the equation proposed by Matusita in and the value of morphology index (m) could be determined according to the relationship between n Cited by: 5.
The purpose of this study was the synthesis of lithium disilicate glass-ceramics in the system SiO 2 –Al 2 O 3 –K 2 O–Li 2 O. A total of 8 compositions from three series were prepared. A total of 8 compositions from three series were by: Lithium disilicate glass-ceramics are derived from the SiO 2 –Li 2 O system that was first investigated by Stookey at Corning Glass Works in the s.
They consist of a large volume fraction of up to 70% fine rod-like entangled Li 2 Si 2 O 5 crystals, and a minor amount of lithium orthophosphate (Li 3 PO 4) crystals that are randomly oriented and uniformly dispersed in the. The Li2OSiO2 related glass systems have attracted extensive theoretical and experimental investigations for several decades.
There are three different crystallization sequences commonly reported in lithium disilicate glasses although their contributing factors are unclear. Moreover, the effect of concurrent precipitation of crystalline phases during glass crystallization Cited by: A plot of the DTA crystallization peak height versus nucleation temperature closely resembles the classical nucleation rate curve for lithium disilicate glass whose maximum is at C.
Abstract. In this study, the crystallization of 30Li 2 O15Nb 2 O 5 50SiO 2 5TiO 2 (mol%) glass was examined. The parent glass was prepared by the standard melt quenching method, and the investigations were performed under non-isothermal and isothermal conditions using the DTA, XRD, SEM and EDS by: 4.
The paper aims in correlating isothermal DSC signals to the actual nucleation and crystallization processes in a lithium disilicate glass as determined by optical microscopy. The results show that the DSC signal reflects the change from an initial surface.
Solely, Ray and Day developed a method to assign non-isothermal DTA signals to surface and volume nucleation in lithium disilicate glass by using powders of different particle by: 8.
The crystallization of K2OTiO23GeO2 glass under non-isothermal condition was studied. In powdered glass with particle sizes less than mm, surface crystallization. The preferred crystal orientation of Li2Si2O5 crystallites has been evaluated in several partially crystallized glass fibres with the following chemical composition in mol %: SiO2; Li2O; ZnO; K2O and P2O5.
The crystallites were shown to be grown radially with thec-axis directed from the surface towards the core of the fibre. When glass Cited by: 9.
thermal DTA studies of lithium disilicate glass, which is known to crystallize polymorphically by homoge-neous nucleation. A method for probing the tempera-ture range for significant nucleation is presented and critiqued.
Most methods for the analysis of calori-metric data assume infinitely large samples, while. A well‐defined overshoot in C p is evident on reheating the quenched glass, consistent with numerous dynamic calorimetric studies [Davis and Ihinger, ; Hodge, ; Moynihan et al., ].
Since J ∝ exp(−Δ G * /k b T) (equation (9)), and Δ G * ∝ 1/Δ G r 2, small changes in Δ G r (equation (15)) can lead to significant Cited by: The Avrami exponent, n, activation energy, E, and frequency factor, K 0, were calculated from only one nonisothermal experiment by using the new kinetic equation for amorphous Se (a-Se), polysilane/polycarbosilane (PS/PCS), and lithium disilicate (LiO 2 2SiO 2 or LS 2) samples with nucleation site by: In this study, the crystallization kinetics of LS2 glass ceramic obtained from the base glass of the system SiO2–Li2O–Al2O3–K2O–P2O5 were investigated by.
crystallization kinetics of glasses j. sestak th applicability of dta to the study of crystallization kinetics of glasses phys chem glasses 15 () j. sestak use of phenomenological kinetics and the enthalpy versus temperature diagram (and its derivative - dta) for a better understanding of transition (crystallization) processes in glassesFile Size: 3MB.DSC, SEM–EDS, XRD and high-temperature XRD analysis was used to study thermal and crystallization behaviour of yttrium aluminate glasses prepared in the form of microspheres.
The glasses YA-E (eutectic composition from the pseudo-binary system Al2O3–Y3Al5O12) and YA-G (a composition identical to the stoichiometric Y3Al5O12 (YAG) phase) were prepared by Cited by: 6.Lithium disilicate ceramics undergo a crystallization process during the generation of all-ceramic crowns.
Based on the results reported by Wiedhahn [ ], the e ects of the crystallization process can be veri ed by checking the marginal, proximal, and occlusal t a er the milling pro-cedures.
Shrinkage of approximately. % encountered.