Structural characterisation of apatite coatings

• Published in: Journal of materials science 2004-09, Vol.39 (18), p.5747-5754
• Main Authors: ROGERS, K. D, ETOK, S. E, SCOTT, R
• Format: Article
• Language: English
• Subjects: Apatite; Biological and medical sciences; Cathodic coating (process); Coated electrodes; Coatings; Condensed matter: structure, mechanical and thermal properties; Crystallites; Exact sciences and technology; Hydroxyapatite; Materials science; Medical sciences; Microstrain; Phase composition; Physics; Plasma; Plasma spraying; Preferred orientation; Prostheses; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Sprayed coatings; Structure and morphology; thickness; Substrates; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Technology. Biomaterials. Equipments. Material. Instrumentation; Thin film structure and morphology
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1023/B:JMSC.0000040085.43633.8a

The current, most frequently employed, commercial route to produce hydroxyapatite prosthetic coatings is plasma spraying. However, this has several important limitations especially for textured surfaces. Low temperature methods of coating fabrication such as cathodic electrodeposition are attractive alternatives. However, quantitative characterisation of the phase composition of thin electrodeposited coatings can be problematic. An X-ray diffraction method, which provides quantitative compositional information without reference to external or internal standards, is introduced and validated. The method can also be applied when Bragg peaks from the supporting substrate are apparent within the data and preferred orientation can be tolerated. This method has been used to examine in detail the microstructure of electrodeposited coatings which are compared directly with those formed by a commercial plasma spraying process.We show that, unlike the plasma sprayed coatings, the electrodeposited material consists of a single crystalline phase (hydroxyapatite) and a significantly reduced amorphous phase. The electrodeposited coatings also possess significantly more microstrain and a smaller crystallite size than the corresponding plasma sprayed material.