Electrophoretic Deposition of Microwave Combustion Synthesized Hydroxyapatite and Its Carbon Nanotube Reinforced Nanocomposite on 316L Stainless Steel

Nanohydroxyapatite-carbon nanotube Nanocomposite (HA-CNT) coatings were deposited via electrophoretic deposition (EPD). Hydroxyapatite was synthesized via microwave combustion method using calcium nitrate and glycing as starting materials. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) revealed that pure hydroxyapatite nanoparticles have been synthesized. AISI 316L stainless steel and ethanol were used as substrate and dispersing medium, respectively. 5%wt carbon nanotube (CNT) was used as reinforcing phase. Uniform and macrocrack-free coatings were obtained both for HA and HA-5%wt CNT coatings. Scanning electron microscopy (SEM) showed that most of microcracks in HA coating has eliminated after introducing CNT as reinforcing phase. The variation of deposit weight by time and voltage is measured both for HA and HA-5%wt CNT coatings. Thickness measurements indicated that for both coatings, the thickness increases with deposition voltage. X-ray diffraction patterns indicated that HA has not decomposed after sintering at 850 ˚C for 2 hr in argon atmosphere.