Influence of environment on delayed failure of alumina ceramics

Баринов, С. М.; Ivanov, N. V.; Орлов, С. В.; Shevchenko, V.Ja.

doi:10.1179/bct.2000.99.1.39

Cited by 11 publications

(20 citation statements)

References 12 publications

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“…Actually, a small quantity of glass could seriously deteriorate the subcritical crack growth resistance of alumina ceramics. For example, Barinov et al 28 reported an n value of 60.1 for a high-purity alumina (99.5 wt.% alumina, 0.4 wt.% MgO, and 0.1% silica and alkali oxides). When 5 wt.% glasses were added to the alumina as sintering aids, the n values decrease to 32.3-35.9.…”

Section: Discussionmentioning

confidence: 97%

Subcritical crack growth behavior of Al₂O₃‐glass dental composites

Zhu

Dortmans²,

Feenstra

2003

J Biomed Mater Res

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The purpose of this study is to investigate the subcritical crack growth (SCG) behavior of alumina-glass dental composites. Alumina-glass composites were fabricated by infiltrating molten glass to porous alumina preforms. Rectangular bars of the composite were subject to dynamic loading in air, with stressing rates ranging from 0.01 MPa/s to 2 MPa/s. The SCG parameter n was determined to be 22.1 for the composite, which is substantially lower than those of high-purity dense alumina. Investigations showed that glass phases are responsible for the low n value as cracks propagate preferentially within glass phases or along the interface between glass phases and alumina phases, due to the fact that glasses are more vulnerable to chemical attacks by water molecules under stress corrosion conditions. The SCG behavior of the infiltration glass was also investigated and the SCG parameter n was determined to be 18.7.

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Section: Discussionmentioning

confidence: 97%

Subcritical crack growth behavior of Al₂O₃‐glass dental composites

Zhu

Dortmans²,

Feenstra

2003

J Biomed Mater Res

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“…The glass phase is more susceptible to stress-corrosion, and SCG occurs through the bulk glass phase or the glass-ceramic interface [18, 21, 26]. Previous studies also observed significant influence of the glass matrix in the slow crack growth behavior of these glass-infiltrated composites [26, 42, 43]. …”

Section: Discussionmentioning

confidence: 99%

Effect of the microstructure on the lifetime of dental ceramics

et al. 2011

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Objectives To evaluate the effect of the microstructure on the Weibull and slow crack growth (SCG) parameters and on the lifetime of three ceramics used as framework materials for fixed partial dentures (FPDs) (YZ - Vita In-Ceram YZ; IZ - Vita In-Ceram Zirconia; AL - Vita In-Ceram AL) and of two veneering porcelains (VM7 and VM9). Methods Bar-shaped specimens were fabricated according to the manufacturer’s instructions. Specimens were tested in three-point flexure in 37°C artificial saliva. Weibull analysis (n=30) and a constant stress-rate test (n=10) were used to determine the Weibull modulus (m) and SCG coefficient (n), respectively. Microstructural and fractographic analyses were performed using SEM. ANOVA and Tukey’s test (α=0.05) were used to statistically analyze data obtained with both microstructural and fractographic analyses. Results YZ and AL presented high crystalline content and low porosity (0.1–0.2%). YZ had the highest characteristic strength (σ0) value (911 MPa) followed by AL (488 MPa) and IZ (423 MPa). Lower σ0 values were observed for the porcelains (68–75 MPa). Except for IZ and VM7, m values were similar among the ceramic materials. Higher n values were found for YZ (76) and AL (72), followed by IZ (54) and the veneering materials (36–44). Lifetime predictions showed that YZ was the material with the best mechanical performance. The size of the critical flaw was similar among the framework materials (34–48 µm) and among the porcelains (75–86 µm). Significance The microstructure influenced the mechanical and SCG behavior of the studied materials and, consequently, the lifetime predictions.

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“…[34][35][36][37][38][39][40][41][42] However, these tend toward more continuous controlled processes, whereas spallation tends toward instantaneous step events, as shown by the AE experiments of Reference 8. Here it had been argued that moisture provided a trigger for the loaded gun of a sulfurexpanded and weakened interface.…”

Section: Proposed Modelmentioning

confidence: 99%