Microstructure and Properties of Electroless Ni-P/Si3N4 Nanocomposite Coatings Deposited on the AW-7075 Aluminum Alloy.

Kazimierz Czapczyk,Paweł Zawadzki,Rafał Talar,Natalia Wierzbicka

doi:10.3390/ma14164487

Kazimierz Czapczyk, Paweł Zawadzki + Show 2 more

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https://doi.org/10.3390/ma14164487

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Abstract

The article presents the results of mechanical and tribological tests of Ni-P/Si3N4 nanocomposite coatings deposited on the AW-7075 aluminum alloy using the chemical reduction method. The influence of the chemical composition on the Vickers microhardness determined by the DSI method was examined. The nanocomposite layers were made of Si3N4 silicon nitride in a polydisperse powder with a particle size ranging from 20 to 25 nm. The influence of the content of the dispersion layer material on the adhesion to the substrate was analyzed. The abrasive wear was tested and determined in the reciprocating motion using the “ball-on-flat” method. The surface topography was examined by the contact method with the use of a profilometer. Based on the obtained test results, it was found that the Ni-P/Si3N4 layers produced in the bath with the Si3N4 nanoparticle content in the amount of 2 g/dm3 are more resistant to wear and show greater adhesion than the Ni-P/Si3N4 layers deposited in the bath with 5 g/dm3 of the dispersion phase. NiP/Si3N4 layers provide protection against abrasive wear under various loads and environmental conditions.

Highlights

The matrix of the composite of layers produced was a solid solution of phosphorus in nickel Ni−P containing
Mazurek et al [24] showed that Ni-B/Si3 N4 composite layers and Ni-B composite layers are characterized by compact structures and a good adhesion to the substrate material
The results show that nanocomposite coatings have better mechanical and tribological properties than the AW-7075 alloy

Summary

Introduction

AW-7075 aluminum alloy is an important construction material in any industry because of its lighter weight and better corrosion resistance compared to steel. Some aluminum alloys have similar mechanical properties to structural steels, such as C45 or C46. In this case, the AW-7075 alloy is often used in the shipbuilding, automotive, railway and especially aviation industries [1]. Aluminum alloys are less resistant to abrasive wear than steel parts. Increasing the tribological properties can be achieved through an anti-wear layer; the appropriate matching of the coating and the substrate depends on their mutual synergism. It is an essential element that determines the proper cooperation of the deposited layer with the aluminum core in selected operating conditions. Aluminum alloys can be coated with various coatings for technical applications [2]

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