Mechanical Properties of Hydroxyapatite Coatings via Plasma Spray Deposition

Hydroxyapatite (HA) coatings deposited via plasma spray deposition have gained significant attention in the field of biomaterials due to their excellent biocompatibility and bioactivity. Understanding the mechanical properties of HA coatings produced through this deposition technique is crucial for their successful application in various biomedical and dental fields. This review aims to provide a comprehensive overview of the mechanical properties of HA coatings produced via plasma spray deposition, including their adhesion strength, hardness, porosity, and fracture behavior.<br/><br/>Adhesion strength is a critical mechanical property of HA coatings, as it ensures their long-term stability and performance. The review highlights the factors influencing the adhesion strength, such as surface preparation, coating parameters, and substrate properties. Use of a resorbable blast media such as apatitic abrasive to roughen the substrate of medical implants prior to the application of HA coating will provide a residue-free, textured surface for effective coating adhesion. Various characterization techniques, including tensile testing, pull-off tests, and scratch tests, have been effectively used to evaluate the adhesion strength of HA coatings produced via plasma spray deposition.<br/><br/>The hardness of HA coatings is another crucial mechanical property, which determines their resistance against wear and deformation. The review discusses the influence of plasma spray parameters, such as feedstock particle size and distribution, spray distance, feed rate, and temperature, on the hardness of HA coatings. Hardness characterization techniques, including indentation testing, have been utilized to assess the mechanical hardness of these coatings.<br/><br/>Porosity is an inherent characteristic of plasma-sprayed HA coatings and significantly affects their mechanical properties. The review examines the impact of spray parameters, such as spray distance, gas flow rate, and powder feedstock, on the porosity of HA coatings. Various imaging and characterization techniques, including scanning electron microscopy (SEM), have been utilized to quantify the porosity of these coatings.<br/><br/>In conclusion, understanding the mechanical properties of hydroxyapatite coatings produced via plasma spray deposition is crucial for their successful application in biomedical and dental fields. By optimizing the deposition parameters and post-processing techniques, it is possible to tailor the mechanical properties of these coatings to meet specific application requirements of the subjet implantable device. Further research is needed to explore advanced characterization techniques and develop innovative strategies to enhance the mechanical performance of plasma-sprayed HA coatings.