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Influence of Sintering Temperature on the Mechanical Properties of Alumina Springs
Author(s) -
Barbieri Rodrigo A.,
Perottoni Cláudio A.,
Zorzi Janete E.
Publication year - 2012
Publication title -
international journal of applied ceramic technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 57
eISSN - 1744-7402
pISSN - 1546-542X
DOI - 10.1111/j.1744-7402.2011.02682.x
Subject(s) - materials science , sintering , spring (device) , ceramic , composite material , fracture (geology) , porosity , molding (decorative) , modulus , stress (linguistics) , structural engineering , linguistics , philosophy , engineering
Low‐pressure injection molding ( LPIM ) was used to produce helical alumina springs. Three sets of springs were sintered at 1550°C, 1600°C and 1650°C to observe the effects on spring constant and fracture stress. Sintered alumina springs were obtained with densities ranging from 94.0% to 97.5% of the theoretical limit. Spring constants were measured from room temperature up to 1100°C. Fracture stress data were analyzed according to W eibull statistics and the method of maximum likelihood. Upon increase of sintering temperature from 1550°C to 1650°C, the spring constant and the W eibull characteristic strength of the alumina springs increases by 15% and 32%, respectively. On the other hand, sintering temperature has a negligible influence on W eibull's modulus. This is because internal bubbles and surface defects introduced in the production stage of the ceramic springs — more than the reduction in porosity with increasing sintering temperature — are critical in determining the reliability of the ceramic springs.