Alumina grains properties

The effect of whisker-matrix interfaces on mechanical properties becomes clear when the same Al203-SiC materials are hot-pressed at different temperatures. While maintaining similar density, similar sizes of alumina grains, and identical whisker volumes, these composites have different fracture toughnesses as shown in Fig. 19. The differences in Klc values between A1203 with ACMC SC-9 SiC and A1203 with Tateho SCW... 

This class of materials was developed to combine the chemical stability of alumina and properties of Si3N4 with ease of sintering. A beta Sialon is formed by substitution of Al and O ions for Si and N in Si3N4 lattice, as Sie-zAlzOzNg-z- The resultant structure contains elongated beta-Sialon grains, typically with some intergranular phase, which could be amorphous or crystalline. Substitution of alumina adds to the chemical stability... 

A similar strategy was used by Lim and co-workers [27-28] to synthesise CNTs/alumina composites to investigate the effect of CNT composition and distribution on the tribological properties of the composite. A significant improvement was obtained when CNTs were localised at alumina grain boundaries [28]. The resulting properties will be discussed later in this review. 

High purity 50% ferrosihcon containing <0.1% Al and C is used for production of stainless steel and corded wire for tires, where residual aluminum can cause harm fill alumina-type inclusions. These are also useflil in continuous cast heats, where control of aluminum is necessary. High purity grades of 50 and 75% ferrosihcon containing low levels of aluminum, calcium, and titanium are used for sihcon additions to grain-oriented electrical steels, where low residual aluminum content contributes to the attainment of desired electrical properties, eg, significant reduction of eddy currents. 

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