Influences of phase transformation and ground surface roughness to strength of zirconia/nickel compounds

The phase transformation of zirconia and the deterioration of ground surface are provided in grinding zirconia/nickel compounds. The present paper describes the influences of these phenomena to the strength of compounds. The bending strength of compounds decreases with an increase of nickel contents. The cracks propagate at the interface between zirconia and nickel in the zirconia-enriched compounds. Monoclinic phase contents increase by phase transformation of zirconia in grinding. However, its increase rate lowers with an increase of nickel contents. The bending strength of compounds increases with more zirconia by phase transformation after grinding, and decreases with more nickel than about 50wt% nickel contents due to large ground surface roughness. The increase of compressive residual stress in zirconia depends on phase transformation derived by grinding, and the residual stress in nickel changes from tensile to compressive accompanying with more contents of nickel.