Crack resistance and other characteristics of ceramics of partially stabilized zirconia with an iron oxide additive

The strength, toughness, hardness, and crack resistance of ceramics based on zirconia stabilized by yttrium oxide and having iron oxide as a reinforcing component are investigated. Certain features of this material are studied in detail at low and high temperatures. It is established that the ultimate strength in three-point bending is 977 MPa, and the critical coefficient of stress intensityK _Ic for a notched beam can attain 16.7 MPa · m^1/2. Different testing methods are used and analyzed in the investigation of crack resistance. For example, it is shown that in bending a beam indented under a load of 500 N the value ofK _Ic at room temperature is 9.5 MPa · m^1/2 and after cooling to – 140°CK _Ic is 12.3 MPa · m^1/2. For this testing method the dependence ofK _Ic on the length of a radial crackc _av is established. The results are analyzed with the use of additional data and a fractographic investigation.Translated from Ogneupory, No. 2, pp. 2 – 9, February, 1996.