EFFECT OF AL2O3 NANOPARTICLES ON CORROSION BEHAVIOR OF ALUIMNUM ALLOY (AL-4.5 WT% CU-1.5 WT% MG) FABRICATED BY POWDER METALLURGY

Muna Khethier Abbass,Bassma Finner Sultan

doi:10.3846/est.2019.8860

Muna Khethier Abbass, Bassma Finner Sultan

Open Access

https://doi.org/10.3846/est.2019.8860

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Abstract

In this research the effect of Al2O3 nanoparticles on corrosion behavior of aluminum base alloy (Al-4.5 wt% Cu-1.5 wt% Mg) has been investigated. Nanocomopsites reinforced with variable contents of 1, 3 and 5 wt% of Al2O3 nanoparticles were fabricated using powder metallurgy. All samples were prepared from the base alloy powders under the best powder metallurgy processing conditions of 6 hr of mixing time, 450 MPa of compaction pressure and 560 °C of sintering temperature. Density and micro hardness measurements, and electrochemical corrosion tests are performed for all prepared samples in 3.5 wt% NaCl solution at room temperature using potentiostate instrument. It has been found that density and micro hardness of the nanocomposite increase with increasing of wt% Al2O3 nanoparticles to Al matrix. It was found from Tafel extrapolation method that corrosion rates of the nanocomposites reinforced with alumina nanoparticles were lower than that of base alloy. From results of corrosion test by potentiodynamic cyclic polarization method, it was found the pitting corrosion resistance improves with adding of Al2O3 nanoparticles. It was noticed that the pits disappear and the hysteresis loop disappears also from anodic polarization curve.

Highlights

Aluminum matrix composites (AMCs) have been widely studied due to their low density, their good physical and mechanical properties, their good corrosion resistance, high thermal and electrical conductivity (Khichadi, Lande, & Pathan, 2016)
The best method to prepare the nanocomposite material is powder metallurgy (PM) processes due to PM parts that can be mass produced to net shapes or near net shapes, eliminating or reducing the need for subsequent machining operation, wastes very little material – about 97% of the starting powders are converted to product, can be made with a specified level of porosity, to produce porous metal part, better control of compaction and structure and production of impossible parts (Groover, 2010)
The images given by AFM microscope are like topographical maps

Summary

Introduction

Aluminum matrix composites (AMCs) have been widely studied due to their low density, their good physical and mechanical properties, their good corrosion resistance, high thermal and electrical conductivity (Khichadi, Lande, & Pathan, 2016). Aluminum oxide (alumina, Al2O3) is currently one of the most useful oxide ceramics, as it has been used in many fields of engineering such as coatings, heat-resistant materials, abrasive grains, cutting materials and advanced ceramics. This is because alumina is hard, highly resistant towards bases and acids, allows very high temperature applications and has excellent wear resistance (Tok, Boey, & Zhao, 2006). The best method to prepare the nanocomposite material is powder metallurgy (PM) processes due to PM parts that can be mass produced to net shapes or near net shapes, eliminating or reducing the need for subsequent machining operation, wastes very little material – about 97% of the starting powders are converted to product, can be made with a specified level of porosity, to produce porous metal part, better control of compaction and structure and production of impossible parts (Groover, 2010)

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