Main characteristics of calcium phosphate coatings obtained by laser cladding

Laser surface cladding has become an extensively used technique in metallurgical applications in order to improve surface properties of materials. We have proposed this technique in the field of biomaterials to coat the surface of titanium alloy substrates used in orthopaedical implants with a calcium phosphate (CaP) bioceramic to promote the growth of the bone when the implant is inserted in the body. An exhaustive study on the influence of the processing parameters on finished surface, microstructure and superficial composition was carried out. Also, the geometrical features of the CaP coatings were correlated to the relevant processing parameters. Simple linear relationships between the studied clad features and processing parameters have been found. Different techniques applied to characterise the coated samples revealed the gradual composition of the coatings starting with a biphasic calcium phosphate on the surface and ending with a compound between the calcium phosphate and the metallic substrate in the coating–substrate interface.