Addition of a Ceramic Second Phase

Of these, only (i) and (ii) will be discussed in this chapter. Illustrations of these methods of second-phase strengthening are presented below. 

As previously indicated, the methods and techniques used to form such composite materials are not of interest here. Instead, this and the following sections wiU focus 

Also note that the constituents of the starting powders used to obtain ZTA contain 3Y-TZP as the source for Zr02 in the composite ceramics. Observe the change in the bending stress (and fracture toughness) of the Zr02 content as expressed in Fig. 5.36 in terms of 3Y-TZP. The microstructure of the composites shown was sintered at 1400 °C. In Fig. 5.35a, plate-like grains formed in the 

Alumina may be strengthened by other additives, as weU. The most common additives to alumina are iron oxide, titanium oxide, calcium oxide, magnesium oxide, potassium oxide and sodium oxide. 

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