Title: Optimal experiment design for plasma thermal spray parameters at bending loads

Authors: M. Azadi; A. Moridi; G.H. Farrahi

Addresses: Materials Life Estimation and Improvement Laboratory, School of Mechanical Engineering, Sharif University of Technology, Post Code: 11155-9567, Azadi Avenue, Tehran, Iran; Fatigue Workgroup, Vehicle/Engine Laboratory and Validation Department, Irankhodro Powertrain Company (IPCo.), Post Code: 13988-13711, 6 km Special Road, Tehran, Iran. ' Materials Life Estimation and Improvement Laboratory, School of Mechanical Engineering, Sharif University of Technology, Post Code: 11155-9567, Azadi Avenue, Tehran, Iran. ' Materials Life Estimation and Improvement Laboratory, School of Mechanical Engineering, Sharif University of Technology, Post Code: 11155-9567, Azadi Avenue, Tehran, Iran

Abstract: Ceramic thermal barrier coatings are applied on gas turbines and diesel engine components to protect metals from heat and this enhances the service lifetime by means of a reduction in working temperature. In the present paper, optimisation of plasma thermal spray parameters, including feed rate and nozzle distance from the specimen surface is performed by using the design of experiment method. Due to factorial approach, by considering two parameters with three variation levels, nine experiments of bending test are needed. The base material is cast aluminium alloy, A356.0-T7. The coating layers consist of a bond coat, Ni-Cr-Al-Y with a thickness of 150 µm and a top coat, ZrO2-8wt%Y2O3 with a thickness of 350 µm. The results of sensitivity analysis show that target functions including maximum bending force, stress and deflection of specimens are optimised at a feed rate of 30 gr/min and nozzle distance of 80 mm.

Keywords: plasma spraying; thermal barrier coatings; optimisation; bending tests; coating parameters; finite element method; FEM; modelling; ceramic coatings; gas turbines; diesel engines; design of experiments; DOE; aluminium alloys; stress; deflection; feed rate; nozzle distance.

DOI: 10.1504/IJSURFSE.2012.046837

International Journal of Surface Science and Engineering, 2012 Vol.6 No.1/2, pp.3 - 14

Published online: 20 Aug 2014 *

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