Ceramic material fracture resistance

Therefore, a team, led by the University of Alaska-Fairbanks, was formed to study these practical issues (75), including the composition of the ceramic membrane, seals that would join the ceramic and metal materials, membrane performance, and development of a ceramic that would resist warping and fracturing at the high temperatures of the conversion process. 

Kuebler, J., Fracture toughness of ceramics using the SEVNB method from a preliminary study to a standard test method, in Fracture Resistance Testing of Monolithic and Composite Brittle Materials, ASTM STP 1409, ed. J.A. Salem, M.G. Jenkins and G.D. Quinn, ASTM, West Conshohocken, PA, pp. 93-106, January 2002. 

Alternative approaches, termed indentation thermal shock tests , with pre-cracks of known sizes have been used by several authors to assess thermal shock damage in monolithic ceramics. Knoop (Hasselmann et al., 1978 Faber etal, 1981) or Vickers (Gong etal., 1992 Osterstock, 1993 Andersson and Rowcliffe, 1996 Tancret and Osterstock, 1997 Collin and Rowcliffe, 1999, 2000 Lee et al., 2002) indentations were made on rectangular bars, which were then heated to pre-determined temperatures and quenched into water. Crack extensions from the indentations were measured as a function of quench temperature differential, and the critical temperature for spontaneous crack growth (failure) was determined for the material. Fracture mechanics analyses, which took into account measured resistance-curve (7 -curve) functions, were then used to account for the data trends. 

Different parameters impose different requirements on ceramic materials depending on whether fracture resistance or crack propagation resistance is of prime importance. The values of the above parameters for a range of ceramic materials are presented in Table 15.1, where the property dependence of thermal shock behaviour can be observed. A variety of other parameters... 

Alumina is a well-known bioinert ceramic material which can be used in total hip prosthesis and dental implants since it exhibits good biocompatibility, strength, and excellent corrosion resistance.70,71 The application of alumina has some limitations due to poor fracture toughness. The incorporation of ductile phase may lead to the... 

This chapter discusses the behavior, under thermal shock conditions, of epoxy resins toughened with ceramic particulates. Alumina Al203 and silica Si02, which are usually used as filler for insulation materials, and the new ceramic materials silicon carbide SiC and silicon nitride Si3N4 are employed. For these toughened epoxy resins, the thermal shock resistance is evaluated by using fracture mechanics. The difference between experimental and calculated values of the thermal shock resistance is discussed from a fractographic point of view. 

Zirconia-based materials are very strong and fracture-resistant . In addition, these materials bond well to resin cement when the surface is properly treated or primers are used ". Thus in recent years zirconia-based materials have come to be widely used for making the frameworks of all-ceramic dental restorations. 

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