2318 Characterization of Glass-infiltrated Alumina-based Ceramics
A. DELLA BONA1, J.J. MECHOLSKY2, A.A. BARRETT2, and J.A. GRIGGS3, 1Universidade de Passo Fundo, Brazil, 2University of Florida, Gainesville, USA, 3University of Mississippi Medical Center, Jackson, USA

Objective: to characterize the microstructure, composition, and some properties of glass-infiltrated alumina-based ceramics similar to the In-Ceram system (Vita, Germany). Methods:  Materials used were: IA- In-Ceram Alumina (Vita); IAE- In-Ceram Alumina electrophoretically deposited (Vita); AEM- alumina-based ceramic experimental method (Vita); VC- Vitro-Ceram (Angelus, Brazil); TC- Turkom-Cera (Turkom-Ceramic, Malaysia); AG- Alglass (EDG, Brazil); and CC- Ceramcap (Foto-Ceram, Brazil). Ceramic specimens were fabricated following manufacturers' instructions and ISO6872 standard and polished through 1µm alumina abrasive. Semi-quantitative and qualitative analyses were performed using scanning electron microscopy (SEM), electron dispersive spectroscopy (EDS), X-ray diffraction (XRD), and stereology principles for volume fraction (Vv). The elastic modulus (E) and Poisson's ratio (v) were determined using ultrasonic-time-of-flight data measured in an ultrasonic pulser/receiver, and the density (ρ) using a helium pycnometer. Vicker's indenter was used to calculate hardness (H). Bar specimens were loaded in three-point bending to fracture using a universal testing machine with cross-head speed of 1mm/min. Flexural strength (σ3P) was calculated and statistically analyzed using ANOVA, Tukey (α=0.05)* and Weibull (m= modulus)†. Results:

 

σ3P (MPa)*

m†

E (GPa)

v

H (GPa)*

ρ (g/cm3)

Vv (%Al2O3)

IA

489±62a

9.4±4.7

280±1

0.25

12.1±1.1ab

3.8±0.01

74±3

IAE

485±63a

7.0±2.2

277±3

0.26

12.9±1.1a

3.8±0.01

75±3

AEM

517±37a

16.4±5.5

300±4

0.25

11.3±0.5b

4.0±0.01

70±3

VC

529±67a

8.8±2.9

284±5

0.24

12.4±0.4ab

3.8±0.01

62±3

TC

332±44b

8.9±2.0

245±3

0.25

9.3±0.7c

4.2±0.02

63±3

AG

233±26c

11.6±3.5

239±2

0.25

8.5±0.8c

3.6±0.02

57±2

CC

258±28c

9.0±2.0

167±1

0.23

7.4±0.5d

4.2±0.02

42±2

Similar letters* show no statistical difference (p>0.05). SEM, XRD and EDS analyses revealed similar microstructure for all ceramics, but a lead-based matrix for CC and a zirconia phase for VC. TC, AG and CC showed significantly lower mean σ3P value than the other ceramics (p≤0.05). AEM showed the greatest m (16.4). Conclusion: IA, IAE, AEM and VC ceramics seemed to have similar properties.

CNPq-Brasil:300748/2006-0

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