Effect of annealing close to T on the short-range order of lithium disilicate glass

Buchner, Silvio; Pereira, Altaïr Soria; Lima, J.C. de; Balzaretti, Naira Maria

doi:10.1016/j.jnoncrysol.2021.120729

Cited by 7 publications

(3 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This behavior can be justified because; during the second firing, the glassy phase on the glass ceramics could be partially molten at temperatures above the glass transition temperature (Tg). For the lithium disilicate reinforced glass ceramics, this temperature is around 450°C [ 25 , 26 ]. With the temperature rising, the glass phase becomes less viscous to fill in and seal surface defects such as machining damages [ 27 ].…”

Section: Discussionmentioning

confidence: 99%

Effect of glazing technique and firing on surface roughness and flexural strength of an advanced lithium disilicate

et al. 2023

View full text Add to dashboard Cite

Objective The objective of this study was to investigate the effects of glazing technique and firing on the surface roughness and flexural strength of an advanced lithium disilicate (ALD) and lithium disilicate (LD). Methods Eight groups of bar-shaped specimens (1 mm × 1 mm × 12 mm, N=160, 20/group) were manufactured from ALD (CEREC Tessera, Dentsply Sirona) and LD (IPS e.max CAD, Ivoclar). The specimens were then submitted to various posttreatments: crystallization (c), crystallization followed by a second firing (c-r), crystallization with glaze in one step (cg), and crystallization followed by a glaze layer firing (c-g). Surface roughness was measured by means of a profilometer, and flexural strength was determined using a three-point bending test. Surface morphology, fractography, and crack healing analysis were conducted using scanning electron microscopy. Results Refiring (c-r) did not affect the surface roughness (Ra) while applying glaze at both cg and c-g procedures increased the roughness. ALDc-g (442.3 ± 92.5 MPa) promoted higher strength than ALDcg (282.1 ± 64.4 MPa), whereas LDcg (402.9 ± 78.4 MPa) was stronger than LDc-g (255.5 ± 68.7 MPa). Refiring completely closed the crack in ALD, but it had a limited effect on LD. Conclusions Two-step crystallization and glazing improved ALD strength compared to the one-step protocol. Refiring and one-step glazing do not increase LD’s strength, while two-step glazing has a negative effect. Clinical relevance Besides both materials being lithium-disilicate glass ceramics, the glazing technique and firing protocol affected their roughness and flexural strength differently. A two-step crystallization and glazing should be the first choice for ALD, while for LD, glazing is optional and when necessary, should be applied in one-step.

show abstract

Section: Discussionmentioning

confidence: 99%

Effect of glazing technique and firing on surface roughness and flexural strength of an advanced lithium disilicate

et al. 2023

View full text Add to dashboard Cite

show abstract

“…Recently, Bradtmüller et al, 22 in a combined NMR and MD study, reported atomic-scale structural insights into the effect of sub-T 𝑔 annealing on the structural relaxation of LS 2 glasses. They confirmed that the arrangement of the network modifier in homogeneously nucleating glasses is closely related to those in the isochemical crystals, which was hypothesized by Zanotto et al 23 On the other hand, Buchner et al, [24][25][26][27] in a series of studies, investigated the effect of processing conditions on the crystallization and properties of lithium silicate glasses using different experimental techniques. They found that processing lithium silicate glasses at high temperature and pressure increased Young's modulus and hardness by around 45% and 25%, respectively, compared to the pristine glass.…”

Section: Introductionmentioning

confidence: 61%

“…On the other hand, Buchner et al., 24–27 in a series of studies, investigated the effect of processing conditions on the crystallization and properties of lithium silicate glasses using different experimental techniques. They found that processing lithium silicate glasses at high temperature and pressure increased Young's modulus and hardness by around 45% and 25%, respectively, compared to the pristine glass.…”

Section: Introductionmentioning

confidence: 99%

Pressure‐driven homogenization of lithium disilicate glasses

Bakhouch,

Buchner,

Silveira

et al. 2024

J Am Ceram Soc.

Self Cite

View full text Add to dashboard Cite

Lithium disilicate glasses and glass–ceramics are good potential candidates for biomedical applications, solid‐state batteries, and serve as models of nucleation and crystal growth. Moreover, these glasses exhibit a phase separation that influences their nucleation and crystallization behavior. The atomistic mechanisms of the phase separation and their pressure dependence are unclear so far. Here, we used molecular dynamics simulations supported by experiments to assess the spatial heterogeneity of lithium disilicate glasses prepared under pressure. We show that the glass heterogeneity decreases with increasing the pressure under which the system was cooled and almost disappears at pressures around 30 GPa. The origin of the heterogeneity is due to the attraction between Li cations to form clustering channels, which decreases with pressure. Through our results, we hope to provide valuable insights and guidance for making glass–ceramics with controlled crystallization.

show abstract

Direct Determination of POSS Cage Structure in a Self‐Assembled Ionic Bridged Silsesquioxane by Using the Total Pair Distribution Function G(r) and Density Functional Theory

Schneid,

de Lima,

Ferreira

et al. 2024

Chemistry An Asian Journal

View full text Add to dashboard Cite

In the present study, both short‐range and long‐range structural features of an ionic bridged silsesquioxane, specifically one containing the 1,4‐diazoniabicyclo[2.2.2]octane chloride group (ISSQ), were elucidated. This ionic silsesquioxane was synthesized via direct polycondensation of a bridged organosilane precursor, without any additional functionalization step. Si‐O‐Si cage structures typical of Polyhedral Oligomeric Silsesquioxanes (POSS) were identified. The average interatomic distances of the POSS cages, including the open T8 cage and the T12 cage for the ISSQ, as well as the T8 cage for a commercially available pendant POSS were determined. It is the first report of the interatomic distance determination of POSS cage; achieved by using total pair distribution function G(r) values obtained through high‐resolution synchrotron X‐ray diffraction combined with density functional theory (DFT) calculations. The application of DFT was crucial for accurately assigning X‐ray peaks and verifying structural details. Furthermore, the analysis of X‐ray diffraction peaks and the examination of crystalline domains via transmission electron microscopy enabled the proposal of a hexagonal arrangement of Si–O–Si cages over long ranges within the ionic bridged silsesquioxane. This proposed arrangement highlights a distinctive structural organization that could impact the material's properties and applications.

show abstract

Effect of annealing close to T on the short-range order of lithium disilicate glass

Cited by 7 publications

References 19 publications

Effect of glazing technique and firing on surface roughness and flexural strength of an advanced lithium disilicate

Effect of glazing technique and firing on surface roughness and flexural strength of an advanced lithium disilicate

Pressure‐driven homogenization of lithium disilicate glasses

Direct Determination of POSS Cage Structure in a Self‐Assembled Ionic Bridged Silsesquioxane by Using the Total Pair Distribution Function G(r) and Density Functional Theory

Contact Info

Product

Resources

About