Surface roughening of single crystal zirconia implanted with xenon

Abstract

Ion implantation is being increasingly used as a means to modify the properties of all classes of material. For example, the hardness of single crystal Y[sub 2]O[sub 3] stabilized cubic zirconia (YSZ) was shown to increase when implanted with Xe[sup +] ions up to a fluence of 7.5 [times] 10[sup 15]Xe[sup +]/cm[sup 2]. Microstructural changes produced in the matrix material as a result of ion implantation included the formation of point defects and dislocation networks. Because the noble gas ions are immiscible with the matrix they may coalesce to from inclusions. At fluences greater than 3 [times] 10[sup 16] Xe[sup +]/cm[sup 2] the formation of fluid and solid noble gas inclusion was found in YSZ. The pressure of the solid inclusions has been calculated to be 1.5 GPa. For shallow implants, the presence of the implanted species can lead to high compressive stresses in the surface layer. These compressive stresses are balanced by tensile stresses in the underlying material and this can lead to the formation of cracks in the subsurface region during fracture which results in copious emission of xenon. In this paper, the first observation of roughening on the as-implanted surface of single crystal ceramics is reported. Themore » materials system which has been considered is the implantation of the (001)-surface of single crystal YSZ by Xe[sup +] ions. These observations were made possible by the use of techniques which have a high sensitivity to changes in surface morphology.« less