Heat-Treatment of Aluminium-Nickel Composite Cold Sprayed Coating

Abstract

Intermetallic compounds, especially aluminides, show good high-temperature strength, oxidation resistance, high melting points, and thus have received considerable attention as potential substitutes for superalloys in high-temperature applications. Aluminides are especially interesting because they are stable up to the critical temperature of ordering, which is close to the melting temperature. In the Al-Ni system, the most studied intermetallics are Ni3Al, NiAl and NiAl3. In the presented study, Al and Ni powders were mixed together with Al2O3 in various proportions to produce dense coatings by low-temperature cold spraying. Two types of post-deposition treatments were applied to produce aluminides, namely furnace heating and resistance spot welding. The former caused a long time diffusion while the latter a self-propagating high temperature synthesis. Both heating methods enabled formations of intermetallic phases. However, the furnace heating provides high porosity. The microstructure of the samples was analyzed by SEM (scanning electron microscope), EDS (energy dispersive X-ray spectroscopy) and XRD (X-ray diffraction) together with microhardness measurements.

Perspectives on Developing Burn Resistant Titanium Based Coatings—An Opportunity for Cold Spraying

“…Furthermore, heat treatment of a Ni-Al bimetallic precursor coating may lead to the formation of Ni3Al, NiAl, and NiAl3, with an augmented increase in porosity observed particularly in cases of low Al content and high heat treatment temperatures [70]. However, heat treatment of Ni-Al bimetallic precursor coating can also result in the formation The investigation of producing composite coatings containing intermetallic compounds via low-temperature post-heat treatment of cold-sprayed bimetallic coatings has been explored in various systems, including Al-Ni, Ni-Ti, Fe-Al, and others.…”

“…Furthermore, heat treatment of a Ni-Al bimetallic precursor coating may lead to the formation of Ni 3 Al, NiAl, and NiAl 3 , with an augmented increase in porosity observed particularly in cases of low Al content and high heat treatment temperatures [70]. However, heat treatment of Ni-Al bimetallic precursor coating can also result in the formation of NiAl 3 and Ni 2 Al 3 without affecting the porosity [71].…”

Advanced Functional Metal-Ceramic and Ceramic Coatings Deposited by Low-Pressure Cold Spraying: A Review

“…Other metals with higher mechanical properties can be deposited in the form of metal-metal composite, e.g., Fe/Al [150], Ti/Al [151], Ni/Zn [152], or by specific powder preparation method, e.g., DLC film by CVD on Ti powder [121]. Nevertheless, some materials are mixed for further intermetallic phase generation in additional PSHT [150,151,153].…”

“…Nevertheless, high porosity forms in the coating. To eliminate the porosity, I proposed resistance spot welder (RSW) heat treatment with simultaneous compression of the electrodes [153]. As a result, the porosity of the coating decreased from 20.8% to 4.6% in conventionally and RSW heat-treated coatings, respectively.…”

Fabrication of In Situ rGO Reinforced Ni–Al Intermetallic Composite Coatings by Low Pressure Cold Spraying with Desired High Temperature Wear Characteristics

“…Recent studies have demonstrated that aluminum-rich alloy coatings exhibit excellent high-temperature oxidation resistance and anti-wear properties [1,2], making them widely applied in the aerospace and automobile industries [3]. Traditional high-temperature oxidation-resistant coatings mainly rely on ceramic coatings such as SiO 2 and Al 2 O 3 .…”