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Passivation of the HAYNES® 214® Nickel-base Superalloy via Pulsed Laser Deposition of Alumina and Chromia Nanocoatings for Degradation Resistance at Elevated Temperatures

Stowe, Eric (2021) Passivation of the HAYNES® 214® Nickel-base Superalloy via Pulsed Laser Deposition of Alumina and Chromia Nanocoatings for Degradation Resistance at Elevated Temperatures. Master's Thesis, University of Pittsburgh. (Unpublished)

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HAYNES® 214® is a nickel-base superalloy that forms a protective alpha alumina (α-Al2O3) scale at temperatures above 950°C, which is necessary for oxidation and corrosion protection. At temperatures lower than 950°C, the formation of a protective α-Al2O3 layer is very difficult due to the significantly slower diffusion of aluminum from within the bulk alloy compared to the faster inward diffusion of oxygen. Due to this, internal precipitates of α-Al2O3 are routinely observed within the subsurface region of the alloy and these precipitates can negatively impact the alloy’s mechanical strength and other material properties.

This thesis investigates the role of using pulsed laser deposited Al2O3 and chromia (Cr2O3) nanocoatings as a means to apply a passivation layer on the surface of the HAYNES® 214® alloy in an effort to provide oxidation and corrosion resistance at a temperature as low as 800°C. Through the use of various material characterization techniques, the use of a Cr2O3 nanocoating about 150 nanometers in thickness is capable of promoting and sustaining the formation of a protective α-Al2O3 scale for durations of at least 100 hours of exposure to air. The Cr2O3-coated alloy also provides superior protection under thermal cycling and hot corrosion conditions. The Al2O3-coated alloy provided intermediate results compared to the uncoated alloy in all isothermal oxidation tests performed; however, when exposed to hot corrosion conditions, the Al2O3-coated alloy performed similarly to the uncoated alloy. The Al2O3-coated alloy did appear to provide some benefit under thermal cycling conditions.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Stowe, Ericers164@pitt.eduers164
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairLee, Jung-Kunjul37@pitt.edujul37
Committee MemberGleeson, Brianbmg36@pitt.edubmg36
Committee MemberChmielus, Markuschmielus@pitt.educhmielus
Date: 3 September 2021
Date Type: Publication
Defense Date: 16 July 2021
Approval Date: 3 September 2021
Submission Date: 21 July 2021
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 205
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Materials Science and Engineering
Degree: MS - Master of Science
Thesis Type: Master's Thesis
Refereed: Yes
Uncontrolled Keywords: HAYNES 214, Oxidation, Hot Corrosion, Nickel-base Superalloys, Al2O3, Cr2O3, Coatings
Date Deposited: 03 Sep 2021 17:36
Last Modified: 03 Sep 2021 17:36


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