Fabrication of Oxide Dispersion Strengthened Bond Coats with Low Al$_{2}$O$_{3}$ Content

Bergholz, Jan; Unocic, Kinga A.; Vassen, Robert; Pint, Bruce A.

doi:10.1007/s11666-017-0550-9

Journal Article

FZJ-2017-04373

Fabrication of Oxide Dispersion Strengthened Bond Coats with Low Al$_{2}$O$_{3}$ Content

Bergholz, J. (Corresponding author)FZJ* ; Pint, B. A. ; Unocic, K. A. ; Vassen, R.FZJ*

2017
Springer Boston, Mass.

Journal of thermal spray technology 26(5), 868 - 879 (2017) [10.1007/s11666-017-0550-9]

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Please use a persistent id in citations: doi:10.1007/s11666-017-0550-9

Abstract: Nanoscale oxide dispersions have long been used to increase the oxidation and wear resistance of alloys used as bond coatings in thermal barrier coatings. Their manufacturing via mechanical alloying is often accompanied by difficulties regarding their particle size, homogeneous distribution of the oxide dispersions inside the powder, involving considerable costs, due to cold welding of the powder during milling. A significant improvement in this process can be achieved by the use of process control agent (PCA) to achieve the critical balance between cold welding and fracturing, thereby enhancing the process efficiency. In this investigation, the influence of the organic additive stearic acid on the manufacturing process of Al2O3-doped CoNiCrAlY powder was investigated. Powders were fabricated via mechanical alloying at different milling times and PCA concentrations. The results showed a decrease in particle size, without hindering the homogeneous incorporation of the oxide dispersions. Two powders manufactured with 0.5 and 1.0 wt.% PCA were deposited by high velocity oxygen fuel (HVOF) spraying. Results showed that a higher content of elongated particles in the powder with the higher PCA content led to increased surface roughness, porosity and decreased coating thickness, with areas without embedded oxide particles.

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