Stress influence on interface in plasma-sprayed hydroxyapatite coatings on titanium alloy

✍ Scribed by Millet, P. ;Girardin, E. ;Braham, C. ;Lodini, A.

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 298 KB
• Volume: 60
• Category: Article
• ISSN: 0021-9304
• DOI: 10.1002/jbm.10140

✦ Synopsis

Abstract

During clinical use of hydroxyapatite‐coated implants, mechanical stresses are added to pre‐existing residual stresses. The magnitude of these stresses affects the coating's performance. In this work we studied, by neutron diffraction and conventional X‐ray diffraction methods, the macrostresses induced by a plasma‐spraying process in the coating and at the interface. Neutron diffraction is one of the most suitable techniques for studying the strain distribution in a bulk material. X‐ray diffraction was used to determine residual stress in the hydroxyapatite coating. Using a neutron diffraction method at the nearest point to the interface, we saw no real difference between the stress observed on coated and that on non‐coated samples. With the X‐ray diffraction method, it appeared that the stress level was compressive on every sample. The major advantage of the neutron diffraction method is that measurements can be made on a thick coating in a nondestructive way. The disadvantage is the large‐gauge volume that we had to use because of the relatively low intensity of the neutron beam. Polishing is necessary for measurements inside the material when using the X‐ray method. This destructive method may alter the stress field of the deposit. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 60: 679–684, 2002