A Molecular Dynamics Investigation of the Temperature Effect on the Mechanical Properties of Selected Thin Films for Hydrogen Separation

Sunday Oyinbo,Tien-Chien Jen

doi:10.3390/membranes10090241

Abstract

In this study, we performed nanoindentation test using the molecular dynamic (MD) approach on a selected thin film of palladium, vanadium, copper and niobium coated on the vanadium substrate at a loading rate of 0.5 Å/ps. The thermosetting control is applied with temperature variance from 300 to 700 K to study the mechanical characteristics of the selected thin films. The effects of temperature on the structure of the material, piling-up phenomena and sinking-in occurrence were considered. The simulation results of the analysis and the experimental results published in this literature were well correlated. The analysis of temperature demonstrated an understanding of the impact of the behaviour. As the temperature decreases, the indentation load increases for loading and unloading processes. Hence, this increases the strength of the material. In addition, the results demonstrate that the modulus of elasticity and thin-film hardness decreases in the order of niobium, vanadium, copper and palladium as the temperature increases.

Highlights

Over the last few years, large digital computers have been used to study different facets of molecular dynamics in liquids, gasses and solids [1]
This study aimed to use molecular dynamics simulation techniques to investigate the effect of temperature on the mechanical properties of the selected thin films of palladium, vanadium, copper and niobium deposited on the vanadium substrate at 0.5 Å/ps loading rate of nanoindentation process
The deformation experienced by the thin film increases

Summary

Introduction

Over the last few years, large digital computers have been used to study different facets of molecular dynamics in liquids, gasses and solids [1]. A thin layer of the metal composite membrane such as palladium (Pd), vanadium (V), copper (Cu) and niobium (Nb), which are coated on vanadium substrate, is of great importance in fuel reforming (hydrogen separation) processes since the much lower cost of vanadium (V), copper (Cu) and niobium (Nb) materials than that of pure palladium or palladium alloy allows the membrane to have enough strength and thickness for the required operating pressure and temperature. The thin films mechanical properties, which are not the same with their mass samples, should be deduced precisely for the superior performance of the micro-equipment [2,3]. As the thickness of the thin films reduces in industrial operations, their mechanical characteristics are increasingly difficult to calculate. Environmental conditions of the films such as temperature and moisture can have a direct influence on their mechanical properties [4,5,6]. Few methods exist to measure the surface strength of thin films, which in recent years have gained greater attention from the nanoindentation experiment

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Results

Conclusion