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Effect of Gaseous Environment on Fracture Behavior of AI 2 O 3
Author(s) -
MOUNTVALA A. J.,
MURRAY G. T.
Publication year - 1964
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1964.tb14402.x
Subject(s) - moisture , crystallite , materials science , brittleness , composite material , sapphire , hydrogen , nitrogen , water vapor , hydrate , decomposition , atmospheric temperature range , crystal (programming language) , mineralogy , chemistry , metallurgy , laser , physics , organic chemistry , meteorology , computer science , optics , programming language
The effect of various gaseous atmospheres (nitrogen, hydrogen, and water vapor) on the fracture strength of single‐crystal and poly‐crystalline A1203 was investigated. Sapphire specimens exposed to hydrogen and nitrogen at elevated temperatures and subsequently tested at room temperature did not become brittle or lose strength. Sapphire specimens exposed to moisture in a specific temperature range showed a definite impairment of strength in subsequent room‐temperature bend tests. The strength was recovered when the moisture‐exposed specimens were heated to 400°C. It is suggested that the loss of strength and the recovery are due to the formation and decomposition of a surface precipitate, presumably a hydrate of some type. Polycrystalline alumina (Lucalox) did not show any significant loss in strength when exposed to moisture.