Characteristics of MCrAlY Coatings Sprayed by High Velocity Oxygen-Fuel Spraying System

Itoh, Yoshiyasu; Saitoh, Masahiro; Tamura, Masataka

doi:10.1115/1.483173

Cited by 63 publications

(32 citation statements)

References 9 publications

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“…There were difficulties, however, in relating curvature measurements of coating-substrate couples to actual coating stresses on thick, nonbending substrates. Similar effects of HVOF spray parameters have been reported for other material and spray systems, [18,[28][29][30] although spray particle characteristics are frequently not quantified.…”

Section: Introductionsupporting

confidence: 65%

Residual stresses in high-velocity oxy-fuel metallic coatings

Totemeier

Wright

Swank

2004

Metall Mater Trans A

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X-ray based residual stress measurements were made on type 316 stainless steel and Fe 3 Al coatings that were high-velocity oxy-fuel (HVOF) sprayed onto low-carbon and stainless steel substrates. Nominal coating thicknesses varied from 250 to 1500 m. The effect of HVOF spray particle velocity on residual stress and deposition efficiency was assessed by preparing coatings at three different torch chamber pressures. The effect of substrate thickness on residual stress was determined by spraying coatings onto thick (6.4 mm) and thin (1.4 mm) substrates. Residual stresses were compressive for both coating materials and increased in magnitude with spray velocity. For coatings applied to thick substrates, nearsurface residual stresses were essentially constant with increasing coating thickness. Differences in thermal expansion coefficient between low-carbon and stainless steels led to a 180 MPa difference in residual stress for Fe 3 Al coatings. Deposition efficiency for both materials is maximized at an intermediate (ϳ600 m/s) velocity. Considerations for X-ray measurement of residual stresses in HVOF coatings are also presented.

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Section: Introductionsupporting

confidence: 65%

Residual stresses in high-velocity oxy-fuel metallic coatings

Totemeier

Wright

Swank

2004

Metall Mater Trans A

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“…MCrAlY, where M means Co and/or Ni, coatings have been developed to protect gas turbine blades from oxidation and corrosion at high temperature. 1) Itoh et al 2,3) systematically investigated the mechanical properties of MCrAlY coatings by both four points bending test and resonance method. However, the mechanical properties of the thin MCrAlY coatings used in actual turbine system were unknown, because there was not a proper measurement method of thin sprayed coatings.…”

Section: Introductionmentioning

confidence: 99%

Development of Lateral Compression Method of Circular Tube Thin Coating for Mechanical Properties of Plasma Sprayed CoNiCrAlY

Waki

Kobayashi

2006

Mater. Trans.

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CoNiCrAlY coatings have been developed to protect gas turbine blades from oxidation and corrosion at high temperature. However, the mechanical properties of the thin CoNiCrAlY coatings used in actual turbine system were unknown, because there was not a proper measurement method of thin sprayed coatings. Lateral compression test for the circular tube coatings of plasma-sprayed thin coating was newly developed. In considering the deformation of the tubes, the elastic contact with a flat plate jig and a tube surface was taken into account as well as the bending of the curved beam of the tube. Young's moduli of well known materials obtained from the lateral compression tests agreed well with the true values. CoNiCrAlY tube specimens independent of substrates were manufactured by dissolving out the substrates by nitric acid. The thickness of coatings were selected from 150 to 700 mm. The effects of spraying particle size, spraying atmosphere and thermal treatment on mechanical properties, such as Young's modulus and bending strength, of CoNiCrAlY were examined. It was found that Young's modulus and a fracture stress increased with an increase of the coating thickness. Young's modulus was sensitive to the spraying powder size and increased with a decrease of the size. It was found that spraying with small spraying powder was the most effective in increasing the Young's modulus. It was also found that Young's modulus was governed by the porosity if thickness and process were given. It was found that thermal treatment was the most effective in increasing the bending strength.

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“…Due to the high kinetic energy of the particles, the high velocity oxy-fuel (HVOF) process leads to dense coatings. Furthermore, it has been confirmed that MCrAlY coatings can be produced by HVOF spraying with equivalent mechanical properties to vacuum plasma sprayed MCrAlY coatings ( Ref 4,5). Therefore the developed powder will be sprayed by the HVOF system.…”

Section: Introductionmentioning

confidence: 78%

Development of Oxide Dispersion Strengthened MCrAlY Coatings

et al. 2008

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MCrAlY materials are widely used as bond coats for thermal barrier coatings on turbine blades. The aim of this work is to improve mechanical properties and wear resistance of thermal sprayed NiCoCrAlYcoatings by strengthening the coating with hard phase particles. In order to retain the effect of the dispersion reinforcement at high temperatures, the use of temperature-stable oxide hard phases such as ZrO 2 -Y 2 O 3 is necessary. To realize this new material structure, the high-energy ball-milling process is applied and analyzed. The mixture ratio between NiCoCrAlY and ZrO 2 -Y 2 O 3 was varied between 5 and 10 wt.% ZrO 2 -Y 2 O 3 . The influences of the milling time of the high-energy ball-milling process on the distribution of the hard phases in the metal matrix were analyzed. After spraying with a HVOF system the mechanical properties of the coatings are measured and compared with conventional NiCoCrAlY coatings.

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Characteristics of MCrAlY Coatings Sprayed by High Velocity Oxygen-Fuel Spraying System

Cited by 63 publications

References 9 publications

Residual stresses in high-velocity oxy-fuel metallic coatings

Residual stresses in high-velocity oxy-fuel metallic coatings

Development of Lateral Compression Method of Circular Tube Thin Coating for Mechanical Properties of Plasma Sprayed CoNiCrAlY

Development of Oxide Dispersion Strengthened MCrAlY Coatings

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