Microstructure and properties of DC magnetron sputtered NiAl–Hf coatings (original) (raw)
Related papers
Surface and Coatings Technology
NiAl-0.1 at.% Hf coatings were successfully deposited via direct current magnetron sputtering from an alloy target onto a variety of substrates, including: glass; (1 1 1) oriented Si wafers and CMSX-4 (registered trademark of the Cannon-Muskegon ᭨ Corporation, Muskegon, MI), a second generation Ni-base superalloy. The coatings were characterized using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The as-deposited coatings were found to be crystalline, consisting of the B2 structured NiAl phase, and to exhibit dense columnar Zone T microstructures. Many of the coatings were textured and the degree of texturing was observed to change with the deposition power used and substrates that were used. NiAl coatings deposited on Si at low powers ((50 W) tended to develop random orientations, whereas coatings deposited at higher powers developed strong growth textures. Coatings deposited on Si(1 1 1) exhibited (1 1 1) textures, while coatings deposited on glass exhibited (2 1 1) textures. Thicker coatings (10-mm thick) deposited on CMSX-4 superalloy substrates at 400 W exhibited ᭨ random textures, which could be attributed to the use of higher Ar pressure during deposition. The hardness and the modulus of the different coatings, as measured via nanoindentation testing, varied with crystallographic orientation. Coatings with (1 1 1) and (2 1 1) textures exhibited higher reduced moduli and lower hardness values than randomly oriented coatings, which is in agreement with prior reports on the mechanical behavior of bulk NiAl alloys. Heat treatment of the coatings in argon gas at 500 and 1000 8C for 1 h resulted in decreases in coating hardness, but in no change in the coating modulus. The hardness change is attributed to a combination of grain growth and the annihilation of defects. ᮊ
A preliminary study of DC magnetron sputtered NiAl–Hf coatings
Surface and Coatings Technology, 2003
Crystalline NiAl-0.1Hf coatings, ;20-mm thick, were deposited onto CMSX-4 substrates using direct current (DC) magnetron ᭨ sputtering. The as-deposited coatings were found to be single phase, consisting of b-NiAl (B2 structure). Annealing in argon at 1000 8C for 1 h resulted in densification of the coatings and in increased adhesion between the coatings and the substrate. Microstructural and compositional changes of the coating system after isothermal oxidation were studied using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) techniques. The mechanical properties of the coatings were studied via nanoindentation in the as-deposited condition, after annealing, and following various oxidation heat treatments. The hardness and modulus of the coatings were observed to correlate with oxidation time. Extended oxidation resulted in decreased hardness due to grain growth, precipitate coarsening and the diffusion of solutes into and out of the coating. The results are discussed relative to conventional CVD aluminide coatings.
Microstructure and property analysis of DC magnetron sputtered NiAl–0.6Hf coatings
Surface & Coatings Technology, 2005
In this study NiAl coatings containing 0.6 at.% Hf have been deposited onto CMSX-4 \ substrates via direct current magnetron sputtering. Microstructural analysis using X-ray diffraction (XRD) and transmission electron microscopy (TEM) shows that the as deposited coatings consist of a B2 h-NiAl solid solution phase with no evidence of precipitation. However, it was found that the post-deposition annealing conditions had a great influence on the microstructure of the sputtered coatings. In monolithic coatings extracted from their substrates, nanometer-sized precipitates formed at grain boundaries and within the grain interiors during annealing in argon for 1 h at 1273 K. An increase in the annealing time to 4 h resulted in recrystallization and some grain growth. The microstructure changes of the coatings after isothermal oxidation tests were examined by scanning electron microscopy (SEM) and XRD analysis. The results showed that the heat treatment conditions and Hf concentration in these coatings had a great influence on their oxidation resistance. D
The Influence of Fe Content on the Mechanical Properties of NiAl Coatings Processed In-Situ
Journal of Materials Engineering and Performance, 2014
Your article is protected by copyright and all rights are held exclusively by ASM International. This e-offprint is for personal use only and shall not be self-archived in electronic repositories. If you wish to selfarchive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".
IOP Conference Series: Materials Science and Engineering, 2020
In the present study the thin NiAl intermetallic foils formed on different types of substrates by magnetron sputtering technique were investigated. To provide the deposition of intermetallic NiAl compound in one step without additional heat treatment the composite targets assembled from parts of Al and Al plates were used. The structure of formed thin NiAl coatings was studied using scanning electron microscopy and X-ray diffraction analysis. Mechanical properties were assessed by nanohardness indentation and wear testing of deposited coatings. During sputtering the distance from the target to the substrates varied from 60 to 100 mm to estimate the effect of this parameter on structure and properties of the coatings. The results revealed that thin coatings sputtered at the closer distance from the target to the substrates had the higher hardness about 11 GPa and exhibited the high level of wear properties.
The fine structure of coatings on the basis Ni-Al formed by the magnetron method
2014
Phase composition, fine structure and surface morphology of intermetallic coatings are investigated by X-ray analysis and TEM. It is shown that Ni 3 Al is the main phase of the intermetallic coating for all the investigated samples. There is a Ni-Al phase in the samples of the first type. Three types of grains, differing in size, are discovered in the structure of nanocrystalline coatings: dislocation free, dislocation, and fragmented. The internal stresses, obtained by TEM and X-ray analysis, have close values.
Metals, 2019
By using nc-Ni coatings as a model system, systematic experiments were designed to evaluate the interaction between the microstructural and mechanical properties tailored by electrodeposition conditions. A direct correlation between grain size and texture was established for the first time. The grain size of the (111) crystalline plane decreases with the texture coefficient (RTC) regardless of the process conditions, and that of the (220) plane has different trends. Then, a peculiar phenomenon is revealed that the dependence of hardness on grain size is accurately described by the Hall-Petch relationship when changing the temperature or pH, but with different slopes, while it deviates from such a relationship with changing current density, denoting more underlying mechanisms related to texture. Finally, a surprising degree of influence of texture on hardness and elastic modulus is also presented, with the overall trend of hardness increasing with texture; and when the RTC of (111) e...
Surface and Coatings Technology, 2009
In this study, (Al 0.5 CrFeNiTi 0.25)N x high-entropy films are prepared by a reactive direct current (DC) magnetron sputtering at different N 2 flow rates on silicon wafers. It is found that the structure of (Al 0.5 CrFeNiTi 0.25)N x high-entropy films is amorphous, with x = 0. It transforms from amorphous to a face-centered-cubic (FCC) structure with the increase of nitrogen content, while the bulk Al 0.5 CrFeNiTi 0.25 counterpart prepared by casting features a body-centered-cubic (BCC) phase structure. The phase formation can be explained by the atomic size difference (δ). Lacking nitrogen, δ is approximately 6.4% for the five metal elements, which is relatively large and might form a BCC or ordered-BCC structure, while the metallic elements in this alloy system all have a trend to form nitrides like TiN, CrN, AlN, and FeN. Therefore, nitride components are becoming very similar in size and structure and solve each other easily, thus, an FCC (Al-Cr-Fe-Ni-Ti)N solid solution forms. The calculated value of δ is approximately 23% for this multicomponent nitride solid solution. The (Al 0.5 CrFeNiTi 0.25)N x films achieve a pronounced hardness and a Young's modulus of 21.45 GPa and 253.8 GPa, respectively, which is obviously much higher than that of the as-cast Al 0.5 CrFeNiTi 0.25 bulk alloys.
Electrochemical Behavior of NiAl and Ni3Al Intermetallic Coatings in 1.0 M NaOH Solution
International journal of electrochemical science
Three different grain sizes were used to deposit NiAl and Ni3Al intermetallic coatings on 304 type SS by thermal spraying powder and HVOF (High Velocity Oxygen Fuel) processes. Coatings were characterized by scanning electron microscopy and their characteristics are described as a function of particle size and coating process applied. The corrosion resistance of coatings was evaluated through open circuit potential, potentiodynamic polarization and linear polarization resistance tests in a 1.0 M NaOH solution at room temperature (25 °C). It was observed that the spray process and the particle size have an effect on the electrochemical behavior of coatings tested. Different coatings showed no significant variations in current densities, but were one order of magnitude greater than those of the base alloy; corrosion potentials of coatings were more negative than those of its base alloy regardless of particle size and have similar values.