Flexural strength of glass–ceramic for structural applications

2014 ◽  
Vol 34 (11) ◽  
pp. 2675-2685 ◽  
Author(s):  
Luca Collini ◽  
Gianni Royer Carfagni
Author(s):  
T.R. Dinger ◽  
G. Thomas

The use of Si3N4, alloys for high temperature, high stress structural applications has prompted numerous studies of the oxynitride glasses which exist as intergranular phases in their microstructures. Oxynitride glasses have been investigated recently in their bulk form in order to understand their crystallization behavior for subsequent Si3N4 applications and to investigate their worth as glass-ceramic precursors. This research investigates the crystallization sequence of a glass having a normalized composition of Y26Si30Al11 ON11 and lying in the A1N-Y2O3-SiO2 section of the Y-Si-Al-O-N system. Such glasses exist as intergranular phases in the technologically important Y2O3/Al2O3-fluxed Si3N4 alloys.


2019 ◽  
Vol 44 (2) ◽  
pp. 200-209 ◽  
Author(s):  
F Murillo-Gómez ◽  
RB Wanderley ◽  
MF De Goes

SUMMARY The aim of this study was to determine whether using a silane-containing universal adhesive as a silane primer in glass-ceramic/resin cement systems affects biaxial flexural strength (BFS) and bonded interface integrity after loading. Glass-ceramic (IPS e.max CAD, Ivoclar/Vivadent, Schaan, Liechtenstein) disc-shaped specimens (6.5±0.1mm in diameter, 0.5±0.1mm thick) were etched with 5% hydrofluoric acid (HF) for 20 seconds and divided into four groups of 30 specimens, to be treated as follows: 1) One bottle silane primer (RCP); 2) Separate application of silane and adhesive (RCP+SB); 3) Silane-containing universal adhesive (SBU); 4) No treatment (C). After silanization, all specimens were resin cement– coated and polymerized for 40 seconds. Each specimen layer was measured, as well as each assembly's thickness, using a digital caliper and scanning electron microscope (SEM). Specimens were stored for 24 hours and submitted to a BFS test (1.27 mm/min). BFS values were calculated using the bilayer disc-specimen solution. Bonded interfaces were analyzed on fractured fragments using SEM. One-way ANOVA and Tukey tests (α=0.05) were applied, as well as the Weibull analysis. Factor “silane treatment” was statistically significant (p<0.0001). RCP+SB (372.2±29.4 MPa) and RCP (364.2±29.5 MPa) produced significantly higher BFS than did the C (320.7±36.3 MPa) or SBU (338.0±27.1 MPa) groups. No differences were found in the Weibull modulus (m: RCP: 10.1-17.3; RCP+SB: 10.1-17.0; SBU: 12.3-22.4; C: 7.4-12.9). Bonded interface analysis exhibited ceramic-cement separation (SBU, C) and voids within the resin cement layer (all groups). Neither the ceramic/cement system's BFS nor its bonded interface stability were improved by SBU after loading.


2016 ◽  
Vol 32 ◽  
pp. e15-e16
Author(s):  
F. Murillo-Gómez ◽  
R.B.W. Lima ◽  
M.F. De Goes

Cerâmica ◽  
2016 ◽  
Vol 62 (362) ◽  
pp. 121-127 ◽  
Author(s):  
P. P. Kist ◽  
I. L. Aurélio ◽  
M. Amaral ◽  
L. G. May

Abstract The purpose of the present study was to determine the biaxial flexural strength (BFS) of a CAD/CAM leucite reinforced glass-ceramic ground by diamond burs of different grit sizes and the influence of surface roughness on the BFS. For this, 104 plates were obtained from CAD/CAM ceramic blocks and divided into 4 groups (n = 26), according to bur grit size: extra-fine, fine, medium and coarse. Roughness parameters (Ra, RyMax) were measured, and plates were kept dry for 7 days. The flexural test was carried out and BFS was calculated. Ra, RyMax and BFS data were subjected to analysis of variance and post-hoc test. Weibull analysis was used to compare characteristic strength and Weibull modulus. Regression analysis was performed for BFS vs. Ra and RyMax. When burs with coarse grit were used, higher surface roughness values were found, causing a negative effect on the ceramic BFS (117 MPa for extra-fine, and 83 MPa for coarse). Correlation (r) between surface roughness and BFS was 0.78 for RyMax and 0.73 for Ra. Increases in diamond grit size have a significant negative effect on the BFS of leucite-reinforced glass-ceramics, suggesting that grinding of sintered glass-ceramic should be performed using burs with the finest grit possible in order to minimize internal surface flaws and maximize flexural strength.


2019 ◽  
Vol 821 ◽  
pp. 435-439
Author(s):  
Bo Li ◽  
Ke Jing ◽  
Hai Bo Bian

Low temperature sintered MgO-Al2O3-SiO2 glass-ceramic with high mechanical and low thermal expansion was prepared for package. The remarkable influence of B2O3 addition on the electrical, mechanical, and thermal properties was fully investigated. A small amount of B2O3 promoted the sintering process and improved the densification of MAS. The kinetics via Kissinger method indicated that an appropriate B2O3 content decreased the activation energy and helped the occurrence of crystallization. Due to the increase of crystallinity and indialite phase, B2O3 addition significantly enhanced flexural strength and Young’s modulus. MAS doped with 3wt% B2O3 can be sintered at 900 °C and obtained good properties: σ = 229 MPa, φ = 86 GPa, α = 1.66×10-6 /°C, εr = 5.29, and tanδ = 5.9×10-4.


2011 ◽  
Vol 20 (7) ◽  
pp. 553-560 ◽  
Author(s):  
Luis Gustavo Oliveira de Vasconcellos ◽  
Lucas H. Silva ◽  
Luana Marotta Reis de Vasconcellos ◽  
Ivan Balducci ◽  
Fernando E. Takahashi ◽  
...  

1996 ◽  
Vol 76 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Sharifa A Al-Shehri ◽  
Hamdi Mohammed ◽  
Clive A Wilson

2010 ◽  
Vol 123-125 ◽  
pp. 3-6
Author(s):  
Harry Ku ◽  
Mohan Trada ◽  
Rezwanul Huq

Vinyl ester resin was filled with of glass powder with a view to increasing the flexural strength of the composites for civil and structural applications by a research Centre on composites, University of Southern Queensland (USQ). In order to reduce costs, the Centre wishes to fill as much glass powder as possible to the resin subject to maintaining sufficient strength of the composites in civil and structural applications. This project varies the percentage by weight of the glass powder in the composites, which are then subjected to flexural tests. The flexural strength and strain of the glass powder filled vinyl ester composites decreased with increasing filler content but the flexural modulus was highest at 20 w/t % of glass powder. Scanning Electron Microscope (SEM) was used to analyze the fractured samples and it was found that the fractured surfaces examined were correlated with the flexural properties.


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