Structure and Tribological Properties of Ni–Cr–Al-Based Gradient Coating Prepared by Detonation Spraying

Bauyrzhan Rakhadilov,Madi Abilev,Meruyert Maulet,Zhuldyz Sagdoldina,Rauan Kozhanova

doi:10.3390/coatings11020218

Abstract

In this paper, Ni–Cr–Al coatings were deposited using the detonation spraying method. The aim was to investigate how technological parameters influence coating structure formation, phase composition and tribological performances. We observed that the degree to which the barrel is filled with an O2/C2H2 gas mixture strongly influences the chemical composition of manufactured coatings. High degrees of barrel filling led to a decrease in aluminum content in the coating. Filling degrees of 40% and 50% produced sprayed coatings in which only Ni–Cr phases could be found. When the filling degree was reduced up to 25%, Ni–Al phases began to form in the sprayed coatings. Gradient Ni–Cr–Al coatings were produced by gradually reducing the filling degree from 50% to 25%. These coatings are characterized by Ni–Cr near the substrate level with Ni–Cr and Ni–Al phases at higher levels. The results obtained confirm that gradient Ni–Cr–Al coatings exhibit high hardness as well as good wear resistance.

Highlights

Coatings 2021, 11, 218. https://High-velocity spraying technologies have been intensively investigated of late because of their high-efficiency and properties that allow the development of processes that are easy to automate and apply to practically unlimited sizes of coated surfaces [1,2,3]
We obtained 3.Ni–Cr–Al composite coatings by detonation spraying with varying fill
For spraying powder based on Ni–Cr–Al, the chemical and phase composition coatings produced strongly depend on the degree to which the barrel is filled with an O2 /C2 H2 gas mixture

Summary

Introduction

High-velocity spraying technologies have been intensively investigated of late because of their high-efficiency and properties that allow the development of processes that are easy to automate and apply to practically unlimited sizes of coated surfaces [1,2,3]. These methods can significantly expand the possibilities of conventional flame powder spraying in the field of wear and corrosion protection coatings. Detonation spraying, in particular, offers great promise In this method, a spark plug ignites an explosive reaction and detonates a gas mixture (mainly oxygen and acetylene) that melts and accelerates powder particles. Al and Cr are important components in MCrAl coatings that protect critical turbine components under oxidation and hot corrosion conditions

Methods

Results

Conclusion