| abstract |
This invention is directed to the production of ceramic alloys consisting essentially of partially stabilized ZrO 2 and/or ZrO 2 -HfO 2 solid solution and/or HfO 2 exhibiting high toughness through the inclusion of about 0.5-8 mole %, as expressed on the oxide basis, of YNb0 4 and/or YTaO 4 and/or MNbO 4 and/or MTaO,, wherein M represents Mg +2 , Ca +2 , Sc +3 and/or a rare earth metal ion selected from the group of La +3 , Ce +4 , Ce +3 , Pr +3 , Nd +3 , Sm +3 , Eu +3 , Gd +3 , Tb +3 , DY +3 , HO +3 , Er +3 , Tm +3 , Yb +3 , and Lu +3 substituted for Y, and the use of at least 5 volume percent of such ceramic alloys to toughen hard refractory ceramics. |