Inhibition of metal dusting using thermal spray coatings and laser treatment

Voisey, K.T.; Liu, Z.; Stott, F.H.

Abstract

Alloy 600 and Alloy 800H are susceptible to metal dusting. Both alloys were thermally sprayed with two different corrosion resistant coatings: Ni50Cr and Ni31Cr11Al0.6Y. Laser remelting was used to enhance further the effectiveness of these coatings to resist metal dusting by eliminating interconnected porosity and improving coating adhesion.
Uncoated, coated and laser-treated coated samples of Alloy 600 and Alloy 800H were exposed to a mixed gas atmosphere (20% H2, 80% CO at 650°C). Samples were examined in plan and cross-section using optical and scanning electron microscopy, electron probe microanalysis and X-ray diffraction. The extent of carbon deposition was tracked by mass difference measurements at intervals during exposure.
The thermally sprayed coatings enhanced metal dusting resistance by acting as physical barriers to carbon ingress. The NiCrAlY coating performed well on both substrates. The NiCr coating itself underwent metal dusting and spalled from Alloy 800H due partly to CTE mis-match stresses. Laser treatment of both coatings successfully eliminated interconnected porosity and hence enhanced metal dusting resistance.

Citation

Voisey, K., Liu, Z., & Stott, F. (2006). Inhibition of metal dusting using thermal spray coatings and laser treatment. Surface and Coatings Technology, 201(3-4), https://doi.org/10.1016/j.surfcoat.2005.12.020

• Journal Article Type: Article
• Publication Date: Oct 5, 2006
• Deposit Date: Jan 28, 2015
• Publicly Available Date: Jan 28, 2015
• Journal: Surface and Coatings Technology
• Print ISSN: 0257-8972
• Electronic ISSN: 1879-3347
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 201
• Issue: 3-4
• DOI: https://doi.org/10.1016/j.surfcoat.2005.12.020
• Keywords: Metal dusting; Laser alloying; Laser treatment of coatings; Thermal spray coatings; Corrosion prevention; corrosion resistant coatings
• Public URL: https://nottingham-repository.worktribe.com/output/703821
• Publisher URL: http://www.sciencedirect.com/science/article/pii/S0257897205013691
• Additional Information: NOTICE: this is the author’s version of a work that was accepted for publication in Surface and Coatings Technology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Surface and Coatings Technology, v. 201, issues 3-4, (2006) doi: 10.1016/j.surfcoat.2005.12.020