Effect of yttria-titanium shell-core structured powder on strength and ageing of zirconia/titanium composites

Abstract

Commercially pure titanium powder was modified by a two-step procedure involving attrition milling and subsequent coating with yttria by sol–gel. Lamellar titanium particles with a high aspect ratio were obtained by mechanical grinding. The existence of an yttria layer covering the milled titanium particles (shell–core structure) was corroborated by X-ray photoelectron spectroscopy. Zirconia/titanium (25 vol% titanium) compact specimens were processed by a wet route using the modified titanium powder, spark plasma sintered, and then characterized in terms of mechanical strength and ageing. A reinforcement mechanism arises from the special shape and disposition of the metallic particles. The stable Y2O3 barrier prevents excessive formation of side products at the metal–ceramic interface. Hence, our innovative procedure allows to develop a new ceramic–matrix composite in the interesting zirconia/titanium system with improved mechanical properties and controlled ageing compared to the composites made with commercially pure titanium.