Effect of powder morphology on the microstructure and properties of cold sprayed Ni coatings

Góral, A.; Żórawski, W.; Czaja, Paweł; Lityńska‐Dobrzyńska, Lidia; Makrenek, M.; Kowalski, S.

doi:10.3139/146.111698

Cited by 6 publications

(5 citation statements)

References 26 publications

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“…Therefore, the main advantage of cold-sprayed coatings is the lack of defects typical of thermally sprayed coatings, such as oxidation, evaporation, gas release, and shrinkage porosity. The absence of oxides in cold-sprayed titanium coatings has also been reported by other researchers in the case of powders with angular morphology but different particle size distribution applied as the feedstock material [ 54 , 56 , 66 , 67 , 68 , 69 ]. However, some reports show a negligible increase in the contents of oxygen and nitrogen in the cold-sprayed coatings in comparison with the starting feedstock [ 52 , 57 ].…”

Section: Resultssupporting

confidence: 72%

Experimental and Numerical Investigations of Titanium Deposition for Cold Spray Additive Manufacturing as a Function of Standoff Distance

et al. 2021

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In this research, the cold spray process as an additive manufacturing method was applied to deposit thick titanium coatings onto 7075 aluminium alloy. An analysis of changes in the microstructure and mechanical properties of the coatings depending on the standoff distance was carried out to obtain the maximum deposition efficiency. The process parameters were selected in such a way as to ensure the spraying of irregular titanium powder at the highest velocity and temperature and changing the standoff distance from 20 to 100 mm. Experimental studies demonstrated that the standoff distance had a significant effect on the microstructure of the coatings and their adhesion. Moreover, its rise significantly increased the deposition efficiency. The standoff distance also significantly affected the coating microstructure and their adhesion to the substrate, but did not cause any changes in their phase composition. The standoff distance also influenced the coating porosity, which first decreased to a minimum level of 0.2% and then increased significantly to 9.8%. At the same time, the hardness of the coatings increased by 30%. Numerical simulations confirmed the results of the tests.

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Section: Resultssupporting

confidence: 72%

Experimental and Numerical Investigations of Titanium Deposition for Cold Spray Additive Manufacturing as a Function of Standoff Distance

et al. 2021

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“…The very high roughness of Ni coatings (Table 3) with visible craters confirmed this assumption. On the other hand, the application of finer powders allowed the microstructure to be improved [38,39]. Moreover, quiet crackling was heard during indentation, which confirmed very high stress inside the coatings caused by particles impacting the previously deposited layer with very high velocity.…”

Section: Mechanical Characteristicsmentioning

confidence: 85%

Influence of Surface Preparation on the Microstructure and Mechanical Properties of Cold-Sprayed Nickel Coatings on Al 7075 Alloy

Żórawski,

Góral,

Makrenek

et al. 2023

Materials

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This work presents the effect of surface roughness (Al 7075) on the microstructure and mechanical properties of cold-sprayed nickel coatings. Coating analysis included substrate surfaces and coating geometry, microstructure characterization, microhardness, nanohardness, elastic modulus, and adhesion. The results show that the surface preparation had a significant effect on coating adhesion and microstructure. The coating deposited at the highest gas temperature revealed a dense microstructure, showing very good adhesion of the impacting powder particles to the substrate and good bonding between deposited layers. The Ni grains with different shapes (elongated, equiaxed) and sizes of a few dozen to several hundred nanometres were present in the splats. An increase in temperature caused significant growth in coating thickness as a result of the powder grains’ higher velocity. Moreover, higher gas temperature resulted in the enhancement of micro- and nanohardness, elastic modulus, and adhesion. The adhesive bond strength of Ni coatings in the tested temperature ranges from 500 °C to 800 °C increased with the increase in the surface roughness of the substrate. For the Al 7075 coarse grit-blasted (CG) substrate with the highest roughness, the adhesion reached the highest value of 44.6 MPa when the working gas was at a temperature of 800 °C. There were no distinct dependencies of surface roughness and thickness on the mechanical properties of the cold-sprayed nickel coating.

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“…Adiabatic shear instability takes place when the critical velocity of particles is exceeded, which causes the occurrence of shearing at high pressure, followed by an increase in temperature at the high strain rate of the deformation. The heat generation and high deformation of the powder were mainly localized near the interface region causing the generation of shear bands by adiabatic shear localization [27]. An adiabatic softening of particles favors the good connection of their surfaces by plastic deformation.…”

Section: Residual Stressmentioning

confidence: 99%

“…Ajdelsztajn et al [26] reported that Ni powders of irregular shape are more suitable to obtain a dense coating than spherical ones, because they acquire much higher impact velocity. Góral et al [27] showed that it is possible to produce dense coatings using both dendritic and irregular spherical Ni powders. However, the coating sprayed with dendritic powder exhibited better mechanical properties and significantly lower surface roughness in comparison with the deposit sprayed with spheroidal particles.…”

Section: Introductionmentioning

confidence: 99%

Influence of Nickel Powders on Corrosion Resistance of Cold Sprayed Coatings on Al7075 Substrate

Scendo

Żórawski

Góral

2019

Metals

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The influence of the size and structure of nickel powder grains on the corrosion resistance of nickel coatings on an Al7075 substrate in an acidic chloride solution was investigated. The Ni coating was produced by the cold spraying (CS) method. The surface and microstructure of specimens were observed by a scanning electron microscope (SEM). The corrosion test of the materials was carried out by using the electrochemical method. It has been found that the size of Ni powders has a significant effect on the corrosion resistance of nickel coatings. The porosity of nickel coatings on the Al7075 alloy increases with the increasing size of nickel powders. The corrosion rate of nickel coatings in the chloride environment decreases as the diameter of the nickel powders decreases. On the other hand, the highest corrosion resistance of nickel coatings was obtained using the Ni powders of the irregular spherical or dendritic structure. Moreover, the large particles of nickel powder cause strong residual stress (compared to small grains) in the depth of the nickel coatings.

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Effect of powder morphology on the microstructure and properties of cold sprayed Ni coatings

Cited by 6 publications

References 26 publications

Experimental and Numerical Investigations of Titanium Deposition for Cold Spray Additive Manufacturing as a Function of Standoff Distance

Experimental and Numerical Investigations of Titanium Deposition for Cold Spray Additive Manufacturing as a Function of Standoff Distance

Influence of Surface Preparation on the Microstructure and Mechanical Properties of Cold-Sprayed Nickel Coatings on Al 7075 Alloy

Influence of Nickel Powders on Corrosion Resistance of Cold Sprayed Coatings on Al7075 Substrate

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