A comparative study between alumina added niobia ceramics and two alumina zirconia
composites from nanostructured TZP (7% and 14% weight) was made. On this composites the
zirconia were yttria stabilized and the alumina were submicron structured. As sintering aid a
mixture of magnesia, niobia and talc were used on all samples. The sintering was performed at
1450 oC during 60 minutes. The characteristic grain size and shape of an alumina and zirconia
powders, aggregates and agglomerates were characterized. The sintering ceramics were evaluated
through hardness, fracture toughness and 4 point bending test. Weibull statistic was applied on the
flexural results. Although the fracture toughness result from ZTA were lower, and seems to be
affected by the liquid fase, the hardness and Weibull modulus were higher than alumina niobia. The
grains size and the homogeneity of its distributions on the microstructure of this ceramics was
correlated to these higher values. The results from these alumina zirconia composites showed a
potential to apply as a ballistic armor material.
Coatings of hydroxyapatite — nanosize alpha alumina composites on Ti-6Al-4V