Fabrication of Carbon Nanotube Reinforced Hydroxyapatite Coating on Stainless Steel 316L by Laser Surface Treatment

Abstract

Carbon nanotube reinforced hydroxyapatitecomposite coating (HA/CNT) was fabricated on stainless steel 316L by laser surface alloying (LSA) with a 2.5-kW CW Nd:YAG laser. Metallographical, compositional and phase analysis of the laser-fabricatedcomposite coating were studied by means of scanningelectronmicroscopy (SEM),energy dispersive spectrometry (EDS) and X-ray diffractometry (XRD). In addition, the corrosion behavior of thecomposite coating was investigated bymeans of potentiodynamic polarization technique andelectrochemical impedance spectroscopy.A strong metallurgical bond was formed betweenthe substrateand the coating which was presence of microcracks. The existence of CNT in laser fabricated layer was confirmed by XRD analysis. In addition,the data of electrochemical corrosion studies illustrated the HA/CNT composite coating possessed outstanding corrosion properties compared with the 316L substrate.