Corrosion of Silicon Nitride Materials in Aqueous Solutions. Issue 10 (8th August 2013)

• Record Type: Journal Article
• Authors: Herrmann, M.; Green, D. J.
• Is Part Of: Journal of the American Ceramic Society. Volume 96:Issue 10(2013)
• Page Start: 3009
• Page End: 3022
• Publication Date: 2013-08-08
• Subjects: Ceramics -- Periodicals; 620.1405
• DOI: 10.1111/jace.12509
• Languages: English
• ISSNs: 0002-7820

Abstract

<abstract abstract-type="main" id="jace12509-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <p>Silicon nitride ceramics are used under conditions where high strength, hardness, and wear resistance are necessary. The increasing use of Si₃N₄ ceramics in different environments demands an understanding of the relationships between microstructure and corrosion behavior. This study gives an overview of the behavior of silicon nitride in acids, bases, and hydrothermal conditions. It not only summarizes the literature data but also attempts to explain the mechanisms and to give some guidelines for the use of the materials in different environments. The stability of the ceramics against corrosion in acids and bases up to the boiling point is mostly controlled by the stability of the grain boundary. The stability can be predicted using the glass network theory. Materials with grain boundaries exhibiting a strong network, i.e., a high amount of SiO₂ in the grain boundary, are stable in acids, but less stable under hydrothermal conditions and in basic solutions. Therefore, tailoring the grain boundaries can change the corrosion stability by several orders of magnitude. At temperatures above 200°C–250°C, the dissolution of the Si₃N₄ grains becomes a decisive factor determining the stability.</p> </abstract>