Preparation of MCrAlY–Al2O3 Composite Coatings with Enhanced Oxidation Resistance through a Novel Powder Manufacturing Process

Bai, Mingwen; Song, Bo; Reddy, Liam; Hussain, Tanvir

doi:10.1007/s11666-019-00830-y

Cited by 37 publications

(19 citation statements)

References 50 publications

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“…The reason why XRD did not detect the θ-Al 2 O 3 could because the transformation of θ-α had been completed after the oxidation test [26,27]. However, the morphology of θ-Al 2 O 3 is similar to whiskers, and the whisker-like oxide will be preserved on the surface of α-Al 2 O 3 after the transformation of θ-α [25,[28][29][30]. Hence, we inferred that the surface of the coatings did not generate θ-Al 2 O 3 after VHT but directly generated α-Al 2 O 3 .…”

Section: Discussionmentioning

confidence: 99%

Effect of Vacuum Heat Treatment on the High-Temperature Oxidation Resistance of NiCrAlY Coating

Zheng¹,

Yang²,

Gao³

2020

Coatings

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NiCrAlY coatings were prepared using high-velocity oxygen fuel spraying (HVOF), and the coatings were removed from the substrate to achieve a uniform shape. Vacuum heat treatment (VHT) of the as-sprayed coatings was conducted at different temperatures (1000, 1100, and 1200 °C), and the specimens were subjected to isothermal oxidation exposure testing in air at 1100 °C for up to 21 h. The results show that the high temperature oxidation resistance of the coating increased gradually with the increase in VHT temperature, and the coating of VHT1200 had higher oxidation resistance. The high temperature oxidation resistance of the coating was related to the microstructure transformation of the coating. In VHT coatings, β-NiAl became a dispersed irregular block morphology. The γ’-Ni3Al in VHT1000 presented a granular morphology. However, in VHT1100 and VHT1200, γ’-Ni3Al became a lamellar morphology. This transformation of microstructure promotes the form of exclusive α-Al2O3 scale. With the increase in VHT temperature, the content of yttrium on coatings’ surface was increased and the pores were gradually eliminated. The concentration of yttrium on coatings’ surface prevented the formation of θ-Al2O3 and low porosity was beneficial in improving the internal oxidation of the coating.

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Section: Discussionmentioning

confidence: 99%

Effect of Vacuum Heat Treatment on the High-Temperature Oxidation Resistance of NiCrAlY Coating

Zheng¹,

Yang²,

Gao³

2020

Coatings

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“…Upon the impact, the bonding of coating material takes place by mechanical interlocking. After the solidification of the impacted particles, they form splats in a lamellar manner [36].…”

Section: Coating Characterizationmentioning

confidence: 99%

Effect of powder manufacturing process on characteristics of nanostructured MCrAlY coatings: dry vs. wet ball milling

Zakeri

Tahvili

Bahmani

et al. 2021

jcc

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“…Також протягом останнього десятиліття у практиці газотермічного напилення проводяться дослідження, направлені на створення композиційних покриттів з ультрадисперсними складовими, що забезпечують отримання комплексу підвищених фізико-механічних та експлуатаційних властивостей (зносостійкості, корозійної та ерозійної стійкості, жароміцності). Для отримання таких композиційних покриттів застосовують в основному газополуменеве [1], атмосферне плазмове [2], високошвидкісне газополуменеве [3] або холодне газодинамічне напилення [4,5]. До недоліків покриттів, нанесених зазначеними методами, слід віднести їх високу собівартість, пов'язану із застосуванням горючих та інертних газів; дорогих плакованих або отриманих механічним легуванням порошків; обов'язкове використання дорогого устаткування для нанесення; високі вимоги до кваліфікації робітників.…”

Section: вступunclassified

Formation of Composite Metal-Ceramic and Metal-Carbide Electric Arc Sprayed Coatings

Karpechenko¹,

Bobrov²,

Dubovyу³

et al. 2021

Вісник НТУ "ХПІ"

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The paper studies the possibility of forming composite metal-ceramic (Sv-08G2S-О-Al2O3) and metal-carbide (Sv-08G2S-О-TiC) electric arc sprayed coatings using a hardening phase in the form of powder particles in a free form. For this, a modernized cap of the spray head of an EM-14M electric arc spray gun was used, equipped with a unit for continuous powder feed supply. A laboratory batch of samples was obtained in various technological modes of spraying. Microstructures of the deposited coatings are investigated using a scanning electron microscope. It has been established that composite coatings are characterized by a lamellar structure and a rather low porosity from 8 to 12% (depending on the deposition mode and the hardening phase content), and phase particles of different shades are well differentiated in the structure. The phases were identified by their microhardness indicators. It has been established that the microhardness of the metal matrix (Sv-08G2S-О) is 1.88GPa, ceramic Al2O3 particles ‑ 17.1GPa, TiC particles‑ 31GPa. The influence of the technological parameters of spraying, namely: current, voltage and powder consumption on the content of the hardening phase in the structure of the composite electric arc coatings has been investigated. It was found that when using the maximum values of technological parameters (current 160A, voltage 35V and powder consumption 35 g/min), the maximum content of the hardening phase in the coatings is obtained: 10.3% Al2O3 in metal-ceramic and 25.6% TiC in metal-carbide. The significantly higher maximum TiC content in comparison with the Al2O3 content in composite coatings is explained by the high density of carbide and, as a consequence, the increased velocity of these particles in the high-temperature heterophase jet. Experimental studies of the influence of the content of the strengthening phase in composite coatings on their bond strength to the substrate have been carried out. It is shown that the maximum value of the bond strength of metal-ceramic coatings is 30 MPa and corresponds to the Al2O3 content of 8.7%. As for metal-carbide coatings, the maximum bond strength value of 32 MPa was obtained with a carbide phase content of 18.4%. At the same time, the bond strength of the convention coating sprayed of Sv-08G2S-О wire is 26 MPa. An increase in this characteristic for composite coatings is explained by the additional activation of the sprayed surface by unmelted solid particles of Al2O3 and TiC. It is shown that the decrease in bond strength with an increase in Al2O3 content to 10.3%, and TiC to 25.2% is explained by a significant decrease in the actual contact area of the coating with the substrate.

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Preparation of MCrAlY–Al2O3 Composite Coatings with Enhanced Oxidation Resistance through a Novel Powder Manufacturing Process

Cited by 37 publications

References 50 publications

Effect of Vacuum Heat Treatment on the High-Temperature Oxidation Resistance of NiCrAlY Coating

Effect of Vacuum Heat Treatment on the High-Temperature Oxidation Resistance of NiCrAlY Coating

Effect of powder manufacturing process on characteristics of nanostructured MCrAlY coatings: dry vs. wet ball milling

Formation of Composite Metal-Ceramic and Metal-Carbide Electric Arc Sprayed Coatings

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