Corrosion, wettability and thrombogenicity investigation of ion beam modified HAP/Al 2 O 3 Deep Shikha a , Md. Shahid a , Usha Jha a , Sanjay Kumar Sinha b, * , V. Raghavendra Reddy c , Sunil Ojha d , P. Kumar d , Dinakar Kanjilal d a Department of Chemistry, BIT Mesra, Ranchi 835215, India b Department of Physics, BIT Mesra, Ranchi 835215, India c UGC-DAE Consortium for Scientific Research Indore, India d IUAC, Aruna Asaf Ali road, New Delhi, India highlights . People have worked on HAP coated on metallic alloy and even alumina but the characterization done here are all different.  Throbmobogenicity, corrosion resistance and wetability have all been carried out first time.  Improvement of Surface and interface using energetic inert ions like argon is carried out first time.  The best ion fluence for orthopaedic implants is proposed. article info Article history: Received 5 December 2014 Received in revised form 7 July 2015 Accepted 14 July 2015 Available online 23 July 2015 Keywords: Biomaterials Coatings Surface properties Corrosion abstract Hydroxyapatite Ca 10 (PO4) 6 (OH) 2 , is a biosensitive ceramic which promotes bone growth in human fluid. However due to its weak mechanical strength it is often coated on chemically inert material such as alumina. In the present work hydroxyapatite (HAP) of thickness 1 mm is deposited on alumina using sol egel process and the stoichiometric ratio of Ca:P ¼ 1.67 is maintained. Surface property of HAP is further improved by Ar þ ion implantation. The samples were irradiated with 1.4 MeV Ar þ ions with fluence ranging from 5  10 14 to 1  10 16 ions/cm 2 . After irradiation, the surface is characterized using Atomic Force Microscope (AFM), Scanning Electron Microscope (SEM), electron dispersive X-ray spectroscopy (EDX), Glancing incidence X-ray diffraction (GXRD) and Rutherford backscattering Spectroscopy (RBS) techniques. Corrosion resistances and impedance analysis were carried out in Ringer solution. RBS and EDX were used to confirm the stoichiometric ratio of the film. Compound formation before and after ion implantation was studied using GXRD. Nanohardness, wettability and thrombogenicity of all the samples were studied. Correlation among surface morphology, improvement in corrosion resistance, hardness, wetability and thrombogenicity before and after ion implantation are discussed in this paper. © 2015 Elsevier B.V. All rights reserved. 1. Introduction Human bone and teeth is made up of crystalline form of calcium phosphate which is similar to hydroxyapatite with the chemical formula Ca 10 (PO 4 ) 6 (OH) 2 and often abbreviated as HAP. This com- pound is biocompatible and therefore, has been extensively studied by many research workers [1e6]. However, one of the drawbacks of this compound is its weak mechanical strength, which inhibits the direct implantation into the human body as discussed in literature [1e6]. Many efforts have been made in order to improve the me- chanical properties of this compound [7e10]. Recently, ceramic materials have been given a lot of attention as a candidate for implant material since they possess certain highly desirable characteristics for biomaterial. Ceramics have been used in dentistry for dental crowns owing to their inertness to the body fluids, high compressive strength and good esthetic appearance. The ceramic materials for medical applications were introduced in a given scenario (the 1970s) where failure of the biomaterials, such as steel, Co-alloys and polymethyl methacrylate began to be detected. Such failures lead to the encapsulation of these ceramic * Corresponding author. E-mail address: sksinha@bitmesra.ac.in (S.K. Sinha). Contents lists available at ScienceDirect Materials Chemistry and Physics journal homepage: www.elsevier.com/locate/matchemphys http://dx.doi.org/10.1016/j.matchemphys.2015.07.040 0254-0584/© 2015 Elsevier B.V. All rights reserved. Materials Chemistry and Physics 163 (2015) 272e278