scholarly journals Effect of thermocycling aging on the flexural strength of feldspathic ceramic

2018 ◽  
Vol 21 (3) ◽  
pp. 315
Author(s):  
Ronaldo Lúís Almeida de Carvalho ◽  
Estevão Tomomitsu Kimpara ◽  
Eduardo Bresciani ◽  
Márcia Carneiro Valera ◽  
Renata Marques Melo
Keyword(s):  
Electron Microscopy ◽  
Flexural Strength ◽  
Testing Machine ◽  
Bending Test ◽  
Catastrophic Failure ◽  
Thermal Cycles ◽  
Mean Values ◽  
Three Point Bending ◽  
Universal Testing ◽  
Scanning Electron

<p><strong>Objective: </strong>The aim of the study was to evaluate the effect of aging through different thermocycling protocols on the flexural strength of a feldspathic ceramic. <strong>Material and Methods:</strong> Fifty ceramic bars, Vitablock Mark II (VITA), with dimensions of 18X4X2mm were prepared. The bars were randomly distributed to the groups (n = 10), which were defined according to the number of thermal cycles (TCy): G0 - no TCy; G500 - 500 cycles of TCy; G6000 - 6000 TCy; G10000 - 10000 TCy; G15000 - 15000 TCy. After aging, the specimens were subjected to the three point bending test in a universal testing machine (EMIC DL 1000), under 0.5mm/min speed and loading of 50kgf, until catastrophic failure. A sample of each group was evaluated for topographic morphology under Scanning Electron Microscopy. <strong>Results:</strong> For mechanical testing, the following mean values and standard deviation (MPa) were obtained: G0 (99.78 ± 5.07); G500 (101.64 ± 5.59); G6000 (98.13 ± 4.95); G10000 (91.77 ± 9.68); G15000 (101.51 ± 4.22). An analysis of variance by regression equation (p = 0.387) was performed, demonstrating a weak and non-significant correlation between flexural strength and number of thermal cycles. <strong>Conclusion: </strong>It can be concluded that aging in water solely by different numbers of temperature cycles did not influence on the flexural strength of a feldspathic ceramic.</p><p> </p><p><strong>Keywords</strong></p><p> Material resistance; Aging; Ceramics.</p>

scholarly journals Effect of Glazing on Flexural Strength of Full-Contour Zirconia

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Hattanas Kumchai ◽  
Patrapan Juntavee ◽  
Arthur F. Sun ◽  
Dan Nathanson
Keyword(s):  
Flexural Strength ◽  
Significant Influence ◽  
Testing Machine ◽  
Surface Treatments ◽  
Bending Test ◽  
Three Point Bending ◽  
Universal Testing ◽  
Heat Treated ◽  
Significant Difference ◽  
Post Hoc

Objective. The purpose of this study was to evaluate the effect of glazing on flexural strength of highly translucent zirconia materials. Materials and Methods. Specimens of three brands of zirconia bars (Prettau Zirconia, Zirkonzahn; inCoris TZI, Sirona; and Zirlux FC, Pentron Ceramics) were prepared and polished according to manufacturers’ instructions. Final specimen dimensions were 20 × 4 × 2 mm. The specimens from each brand were divided into 3 groups (N = 10): control, heat-treated, and glazed. Heat-treated specimens were fired without the application of the glaze material. The glaze material was applied to the glazed specimens before being fired. A three-point bending test (15 mm span) was performed in an Instron universal testing machine (ISO 6872). Data were analyzed by ANOVA and Tukey’s HSD post hoc test (α = 0.05). Results. Two-way ANOVA showed a significant influence of surface treatments on flexural strength of zirconia materials (P≤0.05). There was no significant difference in flexural strength among the different brands of highly translucent zirconia (P≥0.05). Tukey’s HSD post hoc test showed that specimens in the “glazed” group had significantly lower flexural strength than the control and heat-treated groups (P≤0.05). Conclusion. Within the limitations of the study, external glazing decreased the flexural strength of highly translucent zirconia.

Effect of Repeated Preheating Cycles on Flexural Strength of Resin Composites

2013 ◽  
Vol 38 (1) ◽  
pp. 33-38 ◽  
Author(s):  
M D'Amario ◽  
S Pacioni ◽  
M Capogreco ◽  
R Gatto ◽  
M Baldi
Keyword(s):  
Flexural Strength ◽  
Room Temperature ◽  
Testing Machine ◽  
Bending Test ◽  
Resin Composites ◽  
Control Groups ◽  
Three Point Bending ◽  
Universal Testing ◽  
Group A ◽  
Significant Factors

SUMMARY The aim of this study was to assess the flexural strengths of three resin composites prepared at room temperature or cured after 20 or 40 cycles of preheating to a temperature of 45°C. Three resin composites were evaluated: Enamel Plus HFO (Micerium) (HFO), Enamel Plus HRi (Micerium) (HRi), Opallis + (FGM) (OPA). One group of specimens for each composite was fabricated under ambient laboratory conditions, whereas in the other groups, the composites were cured after 20 or 40 preheating cycles to a temperature of 45°C in a preheating device. Ten specimens were prepared for each group. A three-point bending test was performed using a universal testing machine at a crosshead speed of 0.5 mm/min. Data were analyzed with a two-way analysis of variance (ANOVA) test and a Games-Howell test (α = 0.05). The two-way ANOVA showed that both the material and the number of heating cycles were significant factors, able to influence the flexural strength values (p&lt;0.05). However, there was not a statistically significant interaction (p&gt;0.05). For all three composites flexural strengths were not affected after 20 preheating cycles in comparison with the control groups (0 preheating cycles) but were, however, significantly decreased when 40 prewarming cycles were conducted. The HRi and OPA groups had the highest flexural strengths, with no statistically significant differences among them. HFO presented significantly lower flexural strengths in comparison with HRi.

scholarly journals PENGEMBANGAN PAPAN PEREDAM BUNYI MELALUI MODIFIKASI NANO SILIKAT AMPAS TEBU PG KREMBOENG DENGAN TEMPLATE SERAT SABUT KELAPA

2019 ◽  
Author(s):  
Hengky Herdianto ◽  
Mochamad Alfi Zahwanul Farich
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Modulus Of Elasticity ◽  
Internal Bond ◽  
Testing Machine ◽  
Sound Level ◽  
Sound Level Meter ◽  
Universal Testing ◽  
Level Meter ◽  
Scanning Electron

Manusia memiliki batas kemampuan mendengar suara pada rentang hingga 140 dB, lebih daripada itu akan terjadi kerusakan pada organ-organ dalam gendang telinga. Ampas tebu PG Kremboeng mengandung 70,97% silikat murni yang berpotensi memberikan penguatan pada papan serat dan meningkatkan performa serap bunyi. Metode yang digunakan untuk sintesis nano silikat ampas tebu dilakukan dengan cara Pretreatment BBA, tukar kation silikat, dan pencucian gel kering. Komponen silikat dan produk lain dalam ampas tebu ditentukan menggunakan difraksi sinar-X (XRD). Morfologi xerogels nano silikat dan papan serat telah diteliti dengan menggunakan Scanning Electron Microscopy (SEM). Daya serap ditentukan dari berat sebelum dan sesudah perendaman dalam air 24 jam. Pengujian keteguhan patah dan Modulus of Elasticity dilakukan dengan Universal Testing Machine. Uji Internal Bond direkatkan pada dua buah blok alumunium dengan perekat besi dan dibiarkan mengering. Koefisien serap diukur dengan sound level meter. Berdasarkan pola XRD, dapat diketahui bahwa terdeteksi medium silicate hydroxide. Berdasarkan mikrograf SEM dapat diketahui suatu struktur bongkahan yang memanjang halus terdiri atas kumpulan-kumpulan partikel nano silikat pada papan dengan template serat sabut kelapa. Sampel terbaik dalam penelitian ini adalah I (60%;17%;23%) dengan nilai DSA 82,38%, MOR 102,84 kg/cm2, MOE 11.228,52 kg/cm2, dan IB 0,83 kg/cm2. Interval nilai koofisien serap taraf intensitas bunyi antar sampel adalah 0,527 &lt; x &lt; 1,000 pada pagi hari, 0,544 &lt; x &lt; 1,000 pada siang hari, dan 0,538 &lt; x &lt; 1,000 pada malam hari. Sehingga secara keseluruhan interval pada segala kondisi waktu adalah 0,527 &lt; x &lt; 1,000.

Studies on Friction and Mechanical Properties of High Density Polypropylene (HDPP) Filled with Modified Talc

2012 ◽  
Vol 624 ◽  
pp. 279-282
Author(s):  
Feng Zhan ◽  
Nan Chun Chen
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Lamellar Structure ◽  
Testing Machine ◽  
High Density ◽  
Impact Testing ◽  
Wear Testing ◽  
Frictional Surface ◽  
Universal Testing ◽  
Scanning Electron

Talc was modified by aluminate coupling agent (ACA) before filling it into high density polypropylene (HDPP) to prepare talc/HDPP composites. Scanning electron microscopy (SEM), wear testing machine, electronic universal testing machine, and impact testing machine were used to analyze the surface modification and the effects of modified talc on friction and mechanical properties of modified talc/HDPP composites. The results indicate that after modified the lamellar structure of talc particles are open and the dispersion of particles are improved, and the edges and corners of surface become softer. Friction properties indicate that when the talc content is 8 wt%, both µ and K are at a lower value, which show that have better wear resistance. The frictional surface is relatively smooth and no furrow trace has found. Mechanical properties show that with talc content increasing, tensile strength and flexural strength of composites increase.

Analysis of the Effect of Cyclic Fatigue on the Flexural Strength of a Ceramoceramic System Used in Dental Prostheses

2018 ◽  
Vol 930 ◽  
pp. 43-47
Author(s):  
Cristiane Fonseca de Carvalho ◽  
Cláudio Luis de Melo-Silva ◽  
Tereza Cristina Favieri de Melo-Silva ◽  
Fábio Amaral de Araújo ◽  
Jefferson Fabricio Cardoso Lins
Keyword(s):  
Flexural Strength ◽  
Ceramic Coating ◽  
Cyclic Fatigue ◽  
Bending Test ◽  
Mean Values ◽  
Three Point Bending ◽  
Cyclic Stresses ◽  
Dental Prostheses ◽  
Before And After ◽  
The Mean

The aim of this study was to analyze the flexural strength of ceramics based on yttria-stabilized zirconia (YTZP) , used in the manufacture of dental prostheses infrastructure before and after aging with cyclic fatigue in moisture. The samples were made by pre-sintered blocks of ZirkonTransluzent (Zirkonzahn GMHB) from YTZP ceramics with and without feldspathic ceramic coating, divided into groups: G1 = YTZP control; G2 = YTZP aged; G3 = YTZP + feldspathic; G4 = YTZP + aged feldspathic. The samples were submitted to a three-point bending test with a speed of 0.5 mm / min. The mean values of the flexural strength values were G1 = 645 MPa (DP ± 124), G2 = 681 MPa (DP ± 129), G3 = 904Mpa (DP ± 157) and G4 = 954Mpa (DP ± 243). The values of groups G1 and G2; G3 and G4 were statistically similar, depending on the presence or absence of coating. Cyclic stresses did not affect the flexural strength of the material

scholarly journals Influence of grinding procedures on the flexural strength of zirconia ceramics

2010 ◽  
Vol 21 (6) ◽  
pp. 528-532 ◽  
Author(s):  
Ufuk İşerı ◽  
Zeynep Özkurt ◽  
Ender Kazazoğlu ◽  
Davut Küçükoğlu
Keyword(s):  
Flexural Strength ◽  
High Speed ◽  
Testing Machine ◽  
Fracture Load ◽  
Bending Test ◽  
Control Group ◽  
Zirconia Ceramics ◽  
Significance Level ◽  
Universal Testing ◽  
Short Time

The surface of zirconia may be damaged during grinding, influencing the mechanical properties of the material. The purpose of this study was to compare the flexural strength of zirconia after different grinding procedures. Twenty bar-type zirconia specimens (21 x 5 x 2 mm) were divided into 4 groups and ground using a high-speed handpiece or a low-speed straight handpiece until the bars were reduced 1 mm using two different grinding times: continuous grinding and short-time grinding (n=5). Control specimens (n=5) were analyzed without grinding. The flexural strengths of the bars were determined by using 3-point bending test in a universal testing machine at a crosshead speed of 0.5 mm/min. The fracture load (N) was recorded, and the data were analyzed statistically by the Kruskal Wallis test at a significance level of 0.05. In the test groups, high-speed handpiece grinding for a short time had produced the highest mean flexural strength (878.5 ± 194.8 MPa), while micromotor continuous grinding produced the lowest mean flexural strength (733.8 ± 94.2 MPa). The control group was the strongest group (928.4 ± 186.5 MPa). However, there was no statistically significant differences among the groups (p>0.05). Within the limitations of the study, there was no difference in flexural strength of zirconia specimens ground with different procedures.

scholarly journals Evaluation of low-fusing ceramic systems combined with titanium grades II and V by bending test and scanning electron microscopy

2003 ◽  
Vol 11 (4) ◽  
pp. 354-360 ◽  
Author(s):  
Wilson José Garbelini ◽  
Guilherme Elias Pessanha Henriques ◽  
Manoel Troia Junior ◽  
Marcelo Ferraz Mesquita ◽  
Cássia Cilene Dezan
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Bond Strength ◽  
Bending Strength ◽  
Bending Test ◽  
Control Group ◽  
Three Point Bending ◽  
Grade Ii ◽  
Titanium Grade ◽  
Scanning Electron

The bond strength by three point bending strength of two metal substrates (commercially pure titanium or grade II, and Ti-6Al-4V alloy or grade V) combined to three distinct low-fusing ceramic systems (LFC) and the nature of porcelain-metal fracture by scanning electron microscopy (SEM) were evaluated. The results were compared to a combination of palladium-silver (Pd-Ag) alloy and conventional porcelain (Duceram VMK68). Sixty metal strips measuring 25x3x0.5mm were made - 30 of titanium grade II and 30 of titanium grade V, with application of the following types of porcelain: Vita Titankeramik, Triceram or Duceratin (10 specimens for each porcelain). The porcelains were bonded to the strips with dimensions limited to 8x3x1mm. The control group consisted of ten specimens Pd-Ag alloy/Duceram VMK68 porcelain. Statistical analyses were made by one-way analysis of variance (ANOVA) and Tukey test at 5% significance level. Results showed that the bond strength in control group (48.0MPa ± 4.0) was significantly higher than the Ti grade II (26.7MPa ± 4.1) and Ti grade V (25.2MPa ± 2.2) combinations. When Duceratin porcelain was applied in both substrates, Ti grade II and Ti grade V, the results were significantly lower than in Ti grade II/Vitatitankeramik. SEM analysis indicated a predominance of adhesive fractures for the groups Ti grade II and Ti grade V, and cohesive fracture for control group Pd-Ag/Duceram. Control group showed the best bond strength compared to the groups that employed LFC. Among LFC, the worst results were obtained when Duceratin porcelain was used in both substrates. SEM confirmed the results of three point bending strength.

Effects of β-Si3N4 Seeds Addition on Microstructure and Mechanical Properties of Porous Si3N4 Ceramics

2012 ◽  
Vol 724 ◽  
pp. 201-204 ◽  
Author(s):  
Fang Li Yu ◽  
Yu Bai ◽  
Jun Du ◽  
Ping Ping Yu ◽  
Jian Zhi Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Flexural Strength ◽  
Porous Si ◽  
Three Point Bending ◽  
Average Aspect Ratio ◽  
Conventional Sintering ◽  
Porous Microstructure ◽  
Sintering Method ◽  
Scanning Electron

Porous Si3N4 ceramics were prepared by conventional sintering method with the initial Si3N4 powder added different amounts of β-Si3N4 seeds and 5 wt.% Y2O3. The porosity, density and flexural strength were tested by Archimedes and three-point bending methods, respectively. Microstructure of porous Si3N4 ceramics was studied by scanning electron microscopy. The results showed that the fibrous β-Si3N4 grains developed in the bimodal porous microstructure and the average aspect ratio of 6.42 by adjusting the β-Si3N4 seeds content up to 3 wt.%. Under the porosity of about 42%, the flexural strength of the materials could reached 315.98 MPa.

Thermophysical and Mechanical Properties of Carbonated Hydroxyapatite

2012 ◽  
Vol 512-515 ◽  
pp. 989-993 ◽  
Author(s):  
Qing Xia Zhu ◽  
Wei Hui Jiang ◽  
Chuan Shao ◽  
Yi Bao
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Sintering Temperature ◽  
Testing Machine ◽  
Carbonate Content ◽  
Flexure Strength ◽  
Carbonated Hydroxyapatite ◽  
Universal Testing ◽  
Calcination Method ◽  
Scanning Electron

The carbonated hydroxyapatite (CHA) was synthesized by precipitation-calcination method. The influences of carbonate subsitution on high-temperature sintering, thermal expansion coefficient (CET) and flexural strength were investigated by the high-temperature dilatometer, scanning electron microscopy (SEM) and universal testing machine. The results showed that the sintering temperatures of CHA were related to the initial carbonate contents. The sintering temperature decreased with increasing initial carbonate contents. The CET of CHAs decreased with the increase of carbonate content, due to the stoma caused by the partially decompostion of CHAs. The CHA ceramics tested were as strong in flexure strength when compared to non-carbonated hydroxyapatite.

Multiscale Characterization of Nanocomposites Fabricated by Copulverization of Epoxy Resin and Nanoclay

Materials ◽  
2005 ◽  
Author(s):  
Levent Aktas ◽  
Sudha Dharmavaram ◽  
M. Cengiz Altan
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Flexural Strength ◽  
Epoxy Resin ◽  
Fine Powder ◽  
Bending Test ◽  
Scanning Electron Micrographs ◽  
Nanoclay Content ◽  
Scanning Electron

Effect of nanoclay on the thermo-mechanical properties of BT250E-1 epoxy resin is investigated. Nanocomposite parts containing 0, 2 and 10wt. % of Cloisite® 30B nanoclay are fabricated by copulverization of nanoclay with epoxy resin at −25°C. Desired amounts of solid epoxy resin and nanoclay are placed into a grinder and copulverized for 20 seconds. The resulting fine powder is then cured using an APA2000 rheometer by using the time-temperature profile provided by the resin supplier. Five disk-shaped parts for each nanoclay content are fabricated. Two rectangular samples are cut out from each disk and used for characterization of mechanical properties and microstructure. Glass transition temperature is observed to deteriorate by 5% and 10% with the addition of 2 and 10wt. % nanoclay, respectively. Three-point bending test results indicate up to 28% improvement in flexural stiffness whereas flexural strength is observed to degrade by 57% over the range of nanoclay loading. Scanning electron microscopy indicates extensive nanoclay agglomeration. In order to characterize the nanoclay cluster morphology, several scanning electron micrographs are captured at 500x magnification. Nanoclay clusters and their size distribution are then identified by digital image processing. It is found that the average cluster size is 2-fold higher at nanocomposites containing 10wt.% nanoclay compared to 2wt.%. Transmission electron microscopy indicates several nanovoids trapped in the intra-cluster regions. The existence of these voids is also verified by density measurements of the cured samples of the epoxy with and without nanoclay. The reduction observed in the flexural strength is believed to be due to these nanovoids and nanoclay agglomeration.

Sign in / Sign up

Export Citation Format

Share Document