Implementation of bioactive glass coatings obtained by thermal spraying to improve the properties of bone implants

Abstract

Nowadays human beings stand out for their increased longevity thanks to scientific and technological advances applied to the field of medicine. One of the most important fields is the replacement or repair of bones and body tissues such as a knee operation or a hip prosthesis. Many of these implants are introduced into the body with the addition of a functional ceramic coating such as hydroxyapatite or bioactive glasses like 45S5 which increase the durability of the prostheses and their replacement time. The main problem that many bioactive glasses suffer comes from their ceramic nature. These materials tend to have a low thermal conductivity, so spraying them becomes a challenge, as they fail to adhere optimally. This work focuses on increasing the adhesion of 45S5 glass sprayed using the Atmospheric Plasma Spray technique on Ti4Al6V substrates using two strategies. The first strategy is to introduce one or more hydroxyapatite interlayers using the demonstrated affinity of HA both 45S5 and substrate in APS. Second strategy, 45S5 agglomerates are produced by using PVA solution to increase the contact area of the particles with the spraying substrate. The mechanical tensile strength of the coatings is evaluated, and the failure mode is characterized by Scanning Electron Microscopy (SEM) to determine which strategy provides the highest adhesion. Finally, to complete the work, an in vitro study of bioactivity and biodegradation of the coatings in body fluids simulated medium is performed to evaluate their compatibility