GEP-based method to formulate adhesion strength and hardness of Nb PVD coated on Ti-6Al-7Nb aimed at developing mixed oxide nanotubular arrays

A R Rafieerad; A R Bushroa; B Nasiri-Tabrizi; A Fallahpour; J Vadivelu; S N Musa; S H A Kaboli

doi:10.1016/j.jmbbm.2016.01.028

GEP-based method to formulate adhesion strength and hardness of Nb PVD coated on Ti-6Al-7Nb aimed at developing mixed oxide nanotubular arrays

J Mech Behav Biomed Mater. 2016 Aug:61:182-196. doi: 10.1016/j.jmbbm.2016.01.028. Epub 2016 Feb 1.

Authors

A R Rafieerad¹, A R Bushroa², B Nasiri-Tabrizi³, A Fallahpour¹, J Vadivelu⁴, S N Musa¹, S H A Kaboli⁵

Affiliations

¹ Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia.
² Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia; Department of Mechanical Engineering, Faculty of Engineering, University of UCLA, Los Angeles, CA 90032, United States; Department of Mechanical and Aerospace Engineering, University of California, CA 90095-1597, United States. Electronic address: bushroa@um.edu.my.
³ Advanced Materials Research Center, Materials Engineering Department, Najafabad Branch, Islamic Azad University, Najafabad, Isfahan, Iran. Electronic address: bahman_nasiri@hotmail.com.
⁴ Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia.
⁵ UM Power Energy Dedicated Advanced Centre (UMPEDAC),University of Malaya, Kuala Lumpur, Malaysia.

PMID: 26874249
DOI: 10.1016/j.jmbbm.2016.01.028

Abstract

PVD process as a thin film coating method is highly applicable for both metallic and ceramic materials, which is faced with the necessity of choosing the correct parameters to achieve optimal results. In the present study, a GEP-based model for the first time was proposed as a safe and accurate method to predict the adhesion strength and hardness of the Nb PVD coated aimed at growing the mixed oxide nanotubular arrays on Ti67. Here, the training and testing analysis were executed for both adhesion strength and hardness. The optimum parameter combination for the scratch adhesion strength and micro hardness was determined by the maximum mean S/N ratio, which was 350W, 20 sccm, and a DC bias of 90V. Results showed that the values calculated in the training and testing in GEP model were very close to the actual experiments designed by Taguchi. The as-sputtered Nb coating with highest adhesion strength and microhardness was electrochemically anodized at 20V for 4h. From the FESEM images and EDS results of the annealed sample, a thick layer of bone-like apatite was formed on the sample surface after soaking in SBF for 10 days, which can be connected to the development of a highly ordered nanotube arrays. This novel approach provides an outline for the future design of nanostructured coatings for a wide range of applications.

Keywords: Anodization; GEP-based model; In-vitro bioactivity; PVD sputtering; Ti–6Al–7Nb.

MeSH terms

Coated Materials, Biocompatible / chemistry*
Hardness
Materials Testing
Microscopy, Electron, Scanning
Nanotubes / chemistry*
Oxides / chemistry*
Surface Properties
Titanium / chemistry*

Substances

Coated Materials, Biocompatible
Oxides
Ti-6Al-7Nb alloy
Titanium