Abstract
The aim of this study is to obtain, by optimizing the deposit parameters, optimal structural and mechanical properties of Ni20Al layers to be applied on a radar station part. The powder was deposited by the process of atmospheric plasma spraying (APS), with a plasma spray (PS) distance of 80, 90 and 100 mm. The coating with the best characteristics was deposited on the hardener of the GTD 2PV8 turbo gas engine for a radar station, in order to reduce the effect of oxidation and vibration on the wear at 450-500°C. The quality of Ni20Al coating layers was assessed on the basis of their microstructure, microhardness and tensile strength. The best structure and mechanical properties were found in the layers deposited with a distance of plasma spray of 80 mm. The surfaces morphology of the deposited coatings and the fracture morphology of the best layers were examined with the SEM (scanning electron microscope). The microstructure of the deposited layers of coatings was examined by light microscopy. The microstructural analysis of the deposited layers was performed according to the Pratt- Whitney standard. The evaluation of the mechanical properties of the layers was done by examining microhardness with the HV0.,3 method and tensile testing was used for the bond strength. Studies have shown that the plasma spray distance significantly affects the mechanical properties and the microstructure of coatings. The effect of Ni20Al coating application has been tested on a hardener of the GTD 2PV8 turbo gas engine on a radar station.
Highlights
The composite Ni20Al nickel - aluminide powder was developed for aviation industry
This paper presents the results of experimental investigations of the influence of the plasma spray distance (PS) on the microstructure and the mechanical properties of the Ni20Al coating layers
The measured values of the microhardness and the bond strength of deposited Ni20Al coatings depending on the plasma spray (PS) distance are shown in Figs. 1 and 2
Summary
The composite Ni20Al nickel - aluminide powder was developed for aviation industry. Its important characteristic is a good deposition by plasma spray at the atmospheric pressure APS. During the plasma spray process, nickel and aluminum react chemically above 660°C and form nickel - aluminide with an exothermic reaction which further transmits heat to the melted particles and to the surface The products of this reaction are formed intermetallic compounds Ni3Al, Ni2Al3 and NiAl which increase the strength and the adhesion of coatings. Aluminum is a chemical element that protects the coating of Ni from oxidation by forming Al2O3 oxide and an intermetallic compound γ'-Ni3Al in the basic alloy α-Ni. At the atmospheric pressure, the Ni20Al powder deposited by the plasma spraying process produces a lamellar coating which consists of the α-Ni solid solution which includes γ'-Ni3Al phases and the NiAl phase in traces (Knotek, Lugscheider, 1976, pp.244251), (Knotek, et al, 1980, pp.282286). The NiO oxides and γ-Al2O3 and pores are between the base lamellas at the interfaces
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
