Hot-pressed calcium phosphates as a potential bone substitute: structural and mechanical characterization

Abstract

The compositional similarity of calcium phosphates such as β-TCP and HAp to the inorganic components of human bones makes them excellent candidates for bone substitutes. Regardless of presenting excellent biocompatibility, calcium phosphates present low mechanical strength, which is a major drawback for load-bearing applications. In this sense, achieving Hap or β-TCP with increased density is crucial to enhance their mechanical properties. In the present study, β-TCP and HAp were processed from commercially available powders in order to obtain highly dense specimens aiming to elevate these mechanical properties of calcium phosphates. For this purpose, two sintering strategies were used: in the first, using a single holding time, whereas in the second, two holding times. The obtained phases, their potential degradation, microstructure, porosity, and mechanical strength were investigated. Results revealed that the use of two holding times improved densification, leading to flexural strength improvement, on both materials, but especially on HAp, where a 122% increase was verified.