Surface properties and in vitro bioactivity of fluorapatite/TiO2 coatings deposited on Ti substrates by Nd: YAG laser cladding

Chi Sheng Chien, Yu Sheng Ko, Tsung Yuan Kuo, Tze Yuan Liao, Huan Chang Lin, Tzer-Min Lee, Ting Fu Hong

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3 Citations (Scopus)

Abstract

Fluorapatite (FA)/TiO2 composite coatings were deposited on Ti-6Al-4V substrates with an Nd:YAG laser cladding process. Two TiO2 powder phases, namely anatase (A) and rutile (R), were used. After cladding, the FA/TiO2(R) specimen had a rougher surface morphology than that of FA/TiO2(A). Both coatings had a cellular-like main microstructure near the interface of the coating (CL) and transition layers (TL). However, a fine metallurgical bonding state was found that existed between CL and TL of the FA/TiO2(R) specimen. The X-ray diffraction (XRD) analysis results show that the coatings of both specimens were composed principally of FA, CaTiO3, and Al2O3 phases. With the high-energy-density laser cladding process, a portion of the FA in the original coating material remained, while all of the TiO2 powder was decomposed and reacted with the Ca in the FA (Ca-rich phase) to produce CaTiO3. Upon immersion of the clad specimens in simulated body fluid, apatite grew more rapidly on the FA/ TiO2(R) coating than on the FA/TiO2(A) coating. The Ca/P ratio of the FA/TiO2(R) specimen approached the ideal bioactivity value after just 2 days of immersion. In contrast, that of the FA/TiO2(A) specimen did not reach the ideal value until 7 days of immersion. Furthermore, a peak corresponding to hydroxycarbonated apatite (HCA) appeared in the XRD patterns of both specimens. For the FA/TiO2(R) specimen, this HCA peak appears after a shorter immersion time. The FA/TiO2(R) specimen with a rougher surface morphology had better in vitro bioactivity than that of FA/TiO2(A).

Original languageEnglish
Pages (from-to)357-366
Number of pages10
JournalJournal of Medical and Biological Engineering
Volume35
Issue number3
DOIs
Publication statusPublished - 2015 Jan 1

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All Science Journal Classification (ASJC) codes

  • Biomedical Engineering

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