Corrosion Behaviour of Different Technical Ceramics in Acids, Basic Solutions and under Hydrothermal Conditions

Abstract

The corrosion behaviour of different technical ceramics (SSiC ,LPS SiC, GPSN, PSZ, TZP, ZTA and alumina) was investigated in acids, bases and under hydrothermal conditions. Besides the mass loss data, the residual strength and the thickness of the corroded layers were used for the characterisation of the corrosion intensity. Investigations in acids, bases and under hydrothermal conditions show that the stability of the materials strongly depends on the composition and the corrosive medium.

Electrochemical corrosion of silicon-infiltrated silicon carbide ceramics in aqueous solutions

“…SiC materials are used on account of their good tribological properties [1] and high corrosion resistance [1][2][3][4]. Silicon-infiltrated SiC (SiSiC) ceramics are also used for wear applications.…”

Electrochemical corrosion of solid and liquid phase sintered silicon carbide in acidic and alkaline environments

“…The standard procedure for measuring corrosion resistance of ceramic materials is the immersion method that involves immersing samples in a corrosive medium and measuring weight loss, corrosion layer depth, residual strength and sometimes the concentration of the corroded ions in the corrosion media. [1][2][3][4][5][6][7] Electrochemical methods are often used to determine corrosion behaviour of metals and hard metals, but are hardly ever used for the analysis of ceramic materials. However, these techniques can also be used to measure the corrosion behaviour of ceramics as long as the ceramics remain electrically conducting.…”

Corrosion of Si3N4-ceramics in aqueous solutions

“…This explanation of the corrosion stability of MgO/Al 2 O 3 -containing materials is in agreement with the fact, that these materials are normally less stable in F − containing media or under hydrothermal conditions. 4,11 Experiments show that the observed relations between corrosion behaviour and composition of the materials is true also for other acids like HCl, HNO 3 , CH 3 COOH. .…”

“…11) at least up to 130 • C (excluding HF) 15 resulting in the observed very strong corrosion layers (corroded porous material shows still a four point bending strength of 400 MPa). 4,5,11 The reason for the different corrosion rates of the nm thick grain boundary films between the grains and the triple junctions could be caused by kinetic factors. Thin SiO 2 -films were observed at the surface of the Si 3 N 4 grains in the corrosion layer (Fig.…”

“…5,7,8 The proposed mechanism of the formation of a stable hydrated SiO 2 -rich network is also in agreement with the different corrosion behaviour of Si 3 N 4 ceramics in HF and under hydrothermal conditions. 4,11,15,[24][25][26][27] The process of formation of a stable passivating SiO 2 network in the ceramics is strongly accelerated by an increasing concentration of SiO 2 in the grain boundary of the ceramics (Fig. 13).…”