Fracture surface, ceramics

Figure C2.11.5. Scanning electron micrographs showing the microstmcture of an alumina ceramic spark-plug body (a) fracture surface and (b) polished and thennally etched cross section.

Fig. 2. RepHca electron micrograph of the fracture surface of enstatite—P-spodumene—zirconia glass-ceramic, showing twinning in the enstatite grains...

Fig. 4. Fracture surface (repHca micrograph) of fluorcanasite glass-ceramic showing interlocking blade-shaped crystals and effects of cleavage splintering...

Fig. 11. Micrographs of (a) a hot-pressed alumina—TiC ceramic showing a white TiC phase and a dark alumina phase (3) and (b) a fracture surface of an...

FIGURE 5.6 This is a fractured sample of a ceramic composite (alumina with 30 volume-percent silicon carbide whiskers). The lighter regions of circular or cylindrical shape are randomly oriented whiskers protruding from the fractured surface. The rod-like depressions in the surface mark places where whiskers nearly parallel with the fracture were pulled out. Courtesy, Roy W. Rice, W. R. Grace and Company. 

SEM images of the fractured surfaces of a monolithic SiC ceramic, uncoated MWCNTs/SiC, and SiC-coated MWCNTs/SiC are shown in Fig. 10.13. All samples were dense and pore-free. For the uncoated MWCNTs/SiC composite,... 

Figure 2. SEM micrograph of fracture surfaces of cordierite-bonded porous SiC ceramics (a) without C addition and (b) with 40 vol.% C, sintered at 1350 °C for 2 h, where the weight ratio of...

Fig.6 SEl micrograph of the fracture surface of Si3N4-AlN composite ceramics with 8wt% La203...

C /SiC-BN composite was fabricated via in situ reaction by applying boron as active filler. The influence of pyrolysis temperatures on ceramic yields and linear shrinkages were studied. At I200°C B4C was synthesized and above 1300°C h-BN appeared as a result of the reaction between boron and N2. There are some fiber pull-outs in both C /SiC composite and C /SiC-BN composite on the fracture surface, otherwise, the layered structure of h-BN can be observed on the fiacture surface of C /SiC-BN composite. 

Mirror. The region around the crack origin. The crack travels in a single plane accelerating as it goes. The fracture surface is smooth and highly reflective. This can be seen in polycrystalline ceramics, but reflectivity is lower. 

Mist. The crack deviates either because it reaches a critical velocity, intersects an inclusion, or there is a change in the internal stresses in the glass. The fracture surface is rougher and less reflective. This region is often difficult to see in polycrystalline ceramics. 

Fig. 3.55 Fracture surface SEM images of the Yb Y203 ceramics sintered at 1800 °C for a 5 h and b 12 h. Reproduced with permission from [290], Copyright 2011, Elsevier...

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