TMMOB Metalurji ve Malzeme Mühendisleri Odas ı E ğ itim Merkezi Bildiriler Kitab ı 1053 19. Uluslararas ı Metalurji ve Malzeme Kongresi | IMMC 2018 Fabrication of Duplex Layer on Pure Titanium (CP-Ti) by Using Electric Arc Sprayed and Plasma Electrolytic Oxidation Method Aysun Ayday, M. Cihan Çalışkan, S. Can Kurnaz, Ahmet Özel, Fatih Üstel Sakarya University, Faculty of Engineering, Department of Metallurgical and Materials Engineering, Sakarya, 54187, Turkey Abstract The electric arc spray (EAS) and plasma electrolytic oxidation (PEO) was coated to improve the composite ceramic coatings on the surface of titanium alloy. The composition of the composite coatings was investigated with X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The cross-section microstructure and micro-hardness of the treated specimens were investigated and analyzed with scanning electron microscopy (SEM) and microhardness tester, respectively. The phase composition of the composite coatings is mainly composed of -Al 2 O 3 , AlP and Al. The hardness of the ceramic coatings is about 720HV 0.1 and 3 times higher than that of the base Keywords: Electric Arc Spray (EAS), Plasma Electrolytic Oxidation (PEO), Aluminum Oxide, 1. Introduction Titanium and its alloys have high strength to weight ratio, excellent mechanical properties and biocompatibility. Thus, titanium and its alloys have been used in aerospace, chemical, petrochemical, sports and biomedicine industries [1-3]. However, titanium and its alloys limit to their various applications such as engineering components because they exhibit poor tribological properties, corrosion resistance [4]. These properties were improved by using some surface engineering methods such as ion implantation, thermal oxidation, chemical or physical vapour deposition, micro arc or plasma electrolytic oxidation [2,4-6]. Recently, PEO is much preferred, but adhesion to the substrate after coating is not very good. In this study duplex coating affect were studied to increase adhesion strength. Duplex coating on Ti alloy was produced by using electric arc spray (EAS) and plasma electrolytic oxidation (PEO) methods. The EAS method was carried out in order to deposit a aluminum layer on CP-Ti substrates at the first step. And then, Al 2 O 3 based on a duplex layer was formed to improve mechanical properties of the Al layer on the EAS surface by PEO process at the second step. 2. Experimental Pure Ti (Cp-Ti) was used as the duplex coating. The samples were machined to be plates with a 1 mm × 15 mm × 60 mm in dimension. The fabrication routes for the duplex EAS/PEO coating is shown in Fig. 1. Fig. 1. Fabrication route for duplex EAS/PEO coating. The current employed in arc spraying was 125A and the spraying voltage was 25 V, and the compressed air pressure was 2 Bar. All wire arc sprayed coatings were carried out using robot arm to obtain homogeny coating thickness. The coating thickness was approximately 290±40 m. Wires were sprayed using a electric wire arc spray gun and robotic system (Sulzer-Metco). The plasma electrolytic oxidation process was conducted on a 10 kW high-power bi-polar pulsed electrical source. Aqueous electrolyte was prepared from solutions of C 4 H 6 CaO 4. H 2 O (8.0 g/L) and Na 3 PO 4 (4.0 g/L) in distilled water and pH of 11.5. The temperature of the solutions was kept at 25– Pretreatment of CP-Ti (Grinding) Coating with wire Al by electric arc spray (EAS) Coating with ceramic oxide by plasma electrolytic oxidation (PEO)