Effect of yttria doping on the microstructure and mechanical properties of Al2O3–FeAl2O4 nanocomposites developed via solid state precipitation

Processing of Alumina and Corresponding Composites

“…Al 2 O 3 -FeAl 2 O 4 nanocomposites, with improved wear resistance as compared to that of single-phase alumina with similar grain sizes, have been produced by solidstate precipitation during the aging of Al 2 O 3 -10 wt% Fe 2 O 3 solid solutions in reducing atmosphere (Mukhopadhyay & Todd, 2010a;Mukhopadhyay & Todd, 2011). The microstructure of the materials was further improved by doping with 250 ppm Y 2 O 3 (Mukhopadhyay & Todd, 2010b. Reaction sintering method has been successfully applied to fabricate alumina-mullite nanocomposites (Burgos-Montes, Moreno, & Baudín, 2010) from mixtures of microsized alumina and colloidal silica.…”

Relationship between microstructure and abrasive wear resistance of Al2O3–FeAl2O4 nanocomposites produced via solid-state precipitation

“…More details about the processing are given in previous reports. [12][13][14] Although several components of the current processing route are not conducive to commercial production (e.g. the use of high purity alumina, ethanol as a dispersion medium, quenching of the specimens) these were included for scientific reasons during the development of these materials and it is anticipated that they can be dispensed with in practice.…”

“…For a given aging time at 1450 • C, the addition of Y 2 O 3 was found to reduce the size of the grain boundary precipitates by approximately a factor of 2, as has been reported previously. 13 This is presumed to be because Y 2 O 3 is known to reduce the grain boundary diffusivity of alumina. [17][18][19] In contrast to the coarser intergranular particles, the intragranular FeAl 2 O 4 particles were in the nanosized regime (<100 nm) even on aging for 20 h at 1450 • C ( Fig.…”

“…[1][2][3][4][5][6][7][8][9] However, such techniques possess serious drawbacks with respect to mass scale commercial productions because as well as being very expensive, they are not suitable for continuous batch production and severely limit the shape and size of the components that can be produced. 2,3,[12][13][14] When less refractory, oxide nanoparticles are incorporated into the powder mixture, pressureless sintering is feasible but the particles tend to coarsen beyond the nanosized regime and adhere to the grain boundaries.…”

“…[12][13][14][15] This avoids both the inhibition of sintering by refractory second phases and the coarsening of oxide phases and may allow commercial exploitation of these promising materials.…”