Properties of HVAF-coatings from Al-Cu-Fe quasicrystalline alloy

DOI: 10.62564/M4-YY1802

Yuriy Yevdokymenko, Mykola Iefimov, Gennadii Frolov, Kateryna Iefimova

Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


Alloys of Al-Cu-Fe system containing quasicrystalline ψ-phase are perspective as thermal barrier, wear-resistant, corrosion-resistant and anti-adhesion coatings. Typically, such alloys are compositions of quasicrystalline and crystalline metallic phases, making them similar to metal ceramics [1]. Until now, high quality thermal spraying coatings from alloys containing ψ-phase more than 70 %(mass) have not been obtained due to its low plasticity at temperatures up to 500°C, phase transition to λ-phase and β-phase at 880°C and narrow area of existence in the diagram of states. The spraying was carried out by HVAF spraying method with liquid fuel burner GVO-RV with flow rate control of two-phase flow parameters, developed in IPMS of NASU [2]. The burner provides spraying powder with temperature 700-1000°C and velocity at least 500 m/s. In this mode the formation of coatings occurs from solid particles due to their plastic deformation. This allows to avoid typical for traditional technologies heating of particles above Tm=1080°С leading to oxidation and evaporation of aluminum resulting in the alloy composition leaving the limits of the existence of ψ-phase. The coatings were sprayed from water atomized Al63Cu25Fe12 powders [3] of fractions +20/-40 µm, +40/-63 µm, +63/-80 µm with the content of ψ-phase 65-75 %(mass). The content of ψ-phase in the coatings was ±5 % compared to powder; in some cases it came to 90 %. The thickness of the coatings is a controllable parameter and may reach 1000 µm. The porosity of coatings on substrates from copper, titanium, steels, aluminum alloys is 4-8 %. The adhesive/cohesive strength of coatings on 1044 steel substrates, determined by the pin method equals to 31±3 MPa. The thermal conductivity coefficient of Al-Cu-Fe coatings increases from 1.9±0.15 W/(m×K) at 20°C to 2.2±0.2 W/(m×K) at 800°C. The resistance of coatings to erosion at jet-abrasive processing is at the level of an HVAF-coating made of stainless steel AISI 301.

Keywords
alloys of Al-Cu-Fe system, quasicrystalline ψ-phase, HVAF-coating

Acknowledgments
Not provided

References
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