were pressed and sintered also in the manner described above each sample was sintered for two hours at the temperatures recorded in table viii vickers hardness measurements gpa and fracture toughness values k ic calculated in terms of mpa u221a m were derived using a 10 kg load table viii__________________________________________________________________________ sinteringexamplecomposition temperature gpa k sub ic__________________________________________________________________________47 90 zro sub 2 3 mole y sub 2 o sub 3 1300 u00b0 c 10 6 4 5 10 ytao sub 4 1400 u00b0 c 10 7 12 6 zro sub 2 7 3 mole yo sub 3 2 1500 u00b0 c microcracked 5 2 mole ytao sub 4 48 96 zro sub 2 2 mole y sub 2 o sub 3 1300 u00b0 c 11 3 13 4 4 ytao sub 4 1400 u00b0 c 10 7 15 5 zro sub 2 3 8 mole yo sub 3 2 1500 u00b0 c 9 5 7 1 2 mole ytao sub 4 49 90 zro sub 2 2 mole y sub 2 o sub 3 1300 u00b0 c 10 1 6 4 10 ytao sub 4 1400 u00b0 c 9 8 13 8 zro sub 2 3 7 mole yo sub 3 2 1500 u00b0 c microcracked 5 3 mole ytao sub 4 50 90 zro sub 2 3 mole y sub 2 o sub 3 1300 u00b0 c 10 4 4 9 10 y nb sub 0 5 ta sub 0 5 o sub 4 1400 u00b0 c.