High temperature degradation behavior of sputtered nanostructured Co–Al coatings on superalloy

Rahman, Atikur; Jayaganthan, R.; Chandra, Ramesh; Ambardar, R.

doi:10.1016/j.apsusc.2012.10.002

Cited by 12 publications

(5 citation statements)

References 30 publications

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“…The high-temperature oxidation behaviour of the bare substrate and CeO 2 coated Superni-75 at 0.1, 0.2 and 0.3 M concentration was also studied by plotting (weight gain/area) 2 versus the number of thermal cycles (Figure 3(b)). The parabolic rate constant k p was calculated from the equation ( W / A ) 2 = k p t , where W / A is the weight gain per unit surface area (mg/cm 2 ) and ‘ t ’ is the time of exposure and k p (g 2 cm 4 s −1 ) is the parabolic rate constant [18,19]. The parabolic rate constants have been listed in Table 2.…”

Section: Resultsmentioning

confidence: 99%

“…Ceria deposited on carbon steel [16] and low alloy steel [17] has also shown to improve the corrosion resistance of the substrate. Since the nature of the scale formed at high temperatures depends on the alloy chemistry as well as on the grain size of the coatings [18,19], so the nano-structured coatings are being extensively studied. It has been proposed by Wang that a higher number of grain boundaries per unit area improve the adherence of the scale [20].…”

Section: Introductionmentioning

confidence: 99%

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Electroless nanoceria films on nickel-based superalloy

Lone

Rahman

2019

Surface Engineering

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Ceria films were deposited by electroless method on a nickel-based superalloy, Superni 75, to improve its performance at high temperatures. Ceria was produced from cerium acetate using triethanolamine as the reducing agent. The films were produced at three concentrations -0.1, 0.2 and 0.3 M of cerium acetate, to study the effect of increasing cerium concentration. For comparative study, the coated and bare substrates were oxidized at 1173 K for 100 h in air. The morphology and the chemistry of the oxide scale formed were analysed using FEG-SEM/EDS and XRD. It has been observed that increasing the cerium concentration in the film increases the oxidation resistance of the substrate which is evident from the calculated parabolic rate constant. It was also observed that the morphology of the scale improves with the increase in the concentration of cerium in the film. The scale formed on the ceria-coated substrate at 0.3 M concentration is dense and more uniform.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electroless nanoceria films on nickel-based superalloy

Lone

Rahman

2019

Surface Engineering

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“…With the increase of temperature and wear debris, the continuous tribofilms were formed on the worn surface like the CoCrAlYTa-10%Al 2 O 3 coatings, as shown in Figure 9c. During the wear process, the Al, Co elements in the coatings would form a compact and continues oxide layer under high temperature and block the diffusion of oxygen from the surface to the inside [39]. The wear debris without serious oxidation had good plasticity, so that the wear debris could be sintered together to form tribofilms.…”

Section: Wear Mechanismsmentioning

confidence: 99%

Effects of Temperature on Wear Properties and Mechanisms of HVOF Sprayed CoCrAlYTa-10%Al2O3 Coatings and H13 Steel

Wei

Hong

et al. 2019

Metals

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In this study, the CoCrAlYTa-10%Al2O3 coatings were prepared by the high-velocity oxygen-fuel (HVOF) spraying. A series of ball-on-disk sliding wear tests were conducted to evaluate the tribological properties of the coatings at different temperatures (25 °C, 200 °C, 400 °C, and 600 °C). The results showed that the average coefficients of friction (COFs) of the CoCrAlYTa-10%Al2O3 coatings were lower than that of H13 steel at different temperatures. The average COFs of the CoCrAlYTa-10%Al2O3 coatings and H13 steel both decreased with increasing temperature. The wear rate of the CoCrAlYTa-10%Al2O3 coatings increased first and then decreased. The microhardness of worn surface of the CoCrAlYTa-10%Al2O3 coatings increased with increasing temperature, while the microhardness of worn surface of H13 steel at 25 °C and 200°C was higher than that at 400 °C and 600 °C. The wear mechanism of the two materials was mainly abrasive wear. The tribofilms were formed on the worn surface of the CoCrAlYTa-10%Al2O3 coatings, which had a good protective effect. Due to thermal softening and low binding strength of debris, it was difficult for H13 steel to form the tribofilms. The wear rate of H13 steel was much higher than that of the CoCrAlYTa-10%Al2O3 coatings at 400 °C and 600 °C, indicating that the high temperature wear resistance of the coatings was much better than that of H13 steel.

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“…The formation of alumina scales may be achieved by pack aluminizing the alloy’s surface [ 13 , 14 , 15 ]. The application of Al-Co coatings could significantly extend the alloy’s lifetime [ 16 , 17 , 18 , 19 , 20 , 21 , 22 ].…”

Section: Introductionmentioning

confidence: 99%

Oxidation of Al-Co Alloys at High Temperatures

et al. 2020

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In this work, the high temperature oxidation behavior of Al71Co29 and Al76Co24 alloys (concentration in at.%) is presented. The alloys were prepared by controlled arc-melting of Co and Al granules in high purity argon. The as-solidified alloys were found to consist of several different phases, including structurally complex m-Al13Co4 and Z-Al3Co phases. The high temperature oxidation behavior of the alloys was studied by simultaneous thermal analysis in flowing synthetic air at 773–1173 K. A protective Al2O3 scale was formed on the sample surface. A parabolic rate law was observed. The rate constants of the alloys have been found between 1.63 × 10−14 and 8.83 × 10−12 g cm−4 s−1. The experimental activation energies of oxidation are 90 and 123 kJ mol−1 for the Al71Co29 and Al76Co24 alloys, respectively. The oxidation mechanism of the Al-Co alloys is discussed and implications towards practical applications of these alloys at high temperatures are provided.

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High temperature degradation behavior of sputtered nanostructured Co–Al coatings on superalloy

Cited by 12 publications

References 30 publications

Electroless nanoceria films on nickel-based superalloy

Electroless nanoceria films on nickel-based superalloy

Effects of Temperature on Wear Properties and Mechanisms of HVOF Sprayed CoCrAlYTa-10%Al2O3 Coatings and H13 Steel

Oxidation of Al-Co Alloys at High Temperatures

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