Coatings to Protect Materials from Extreme Environments: Coatings and Surface Treatments for Extreme Environments
Sponsored by: ACerS Engineering Ceramics Division
Program Organizers: Kang Lee, NASA Glenn Research Center; Yutaka Kagawa, The University of Tokyo; Daniel Mumm, University of California, Irvine; Rodney Trice, Purdue University; Emmanuel Boakye, UES Inc.; Valerie Wiesner, NASA Langley Research Center; Edward Gorzkowski, Naval Research Laboratory; Scooter Johnson, Naval Research Laboratory
Monday 2:00 PM
October 18, 2021
Room: A222
Location: Greater Columbus Convention Center
Session Chair: Daniel Mumm, University of California, Irvine; Edward Gorzkowski, Naval Research Laboratory
2:00 PM
Now On-Demand Only - Aerosol Deposition and Characterization of Sodium Niobate: Eric Patterson1; Heonjune Ryou1; Edward Gorzkowski1; 1U.S. Naval Research Laboratory
Aerosol deposition was used to produce thick-films with layer thicknesses between 10 to 50 microns. The bonding and densification of the film and film/substrate interface facilitated by high pressure, impact and fracture of the particles, and some form of physical-chemical bonding. The films have microstructures characterized by XRD to have nano-grained crystallites and have been shown to have high residual stresses. This inhibits the formation of ferroelectric domains even in the prototypical ferroelectric system of barium titanate, which correlates to the well-known grain size effect in bulk ceramics. Due to these high residual stresses, materials systems that exhibit either antiferroelectric properties in the bulk (such as NaNbO3) or stress-stabilized ferroelectric materials (such as HfO2), are natural alternatives to be studied via this technique. Deposition was performed onto metal substrates to facilitate the characterization of the electrical properties of the films; including permittivity as a function of temperature.
2:30 PM
Functionally Graded Corrosion Resistant Coatings for Molten Salt Reactor Systems: Holly Garich1; Tim Hall1; Stephen Raiman2; Bruce Pint3; 1Faraday Technology; 2Texas A&M University; 3Oak Ridge National Laboratory
Molten salt advanced nuclear reactors are characterized by their use of molten salts, often molten fluorides, as coolants, enabling operation at low pressures, which provides inherent safety benefits over traditional light water reactor designs. Corrosion resistant coatings/overlays are important to maintain integrity of structural materials in these systems. Currently there is a lack of technology that can apply a uniform coating onto complex internal geometries posed by structures such as standard ASME boiler and pressure vessels. This work demonstrates a novel electrodeposition approach that enables application of uniform, functionally graded NiMo alloys onto ASME certified 316H stainless steel substrates. By controlling the deposition conditions, namely the electric field and electrolyte, precise control of alloy composition and grading of alloy composition can be achieved. Alloy properties, including corrosion resistance properties, are presented as a function of processing and post-treatment (hot isostatic press) conditions.
2:50 PM
Effects of Laser Remediation Treatments on Global vs Local Environmentally-assisted Cracking of 5xxx Series Aluminum Alloy Ship Plate: Yang Liu1; John Lewandowski1; 1Case Western Reserve University
5xxx series Al-Mg alloys are solid solution strengthened by Mg and used in a variety of naval applications. However, service exposures at sufficient time/temperature combinations may sensitize the material to corrosion and/or environmentally-assisted cracking (EAC) via precipitation of Mg-rich grain boundary phases. This work determines the effects of service exposure and changes in laser surface remediation treatments (e.g. power, speed) on EAC for service-sensitized 5xxx ship plates. Fracture experiments were conducted in 0.6M NaCl on both service-sensitized and laser remediated ship plate. Changes in crack growth response due to service-sensitization/laser remediation will be presented along with SEM fractography. In addition, the samples have been tested at various thicknesses to isolate the local effects of the laser-treated regions on EAC. Changes in crack growth response due to service-sensitization/laser remediation and samples designed to isolate the laser-treated surface will be presented along with SEM fractography.
3:10 PM Break
3:30 PM
Electrodeposition of Functionally-graded Interlayers for Joining Plasma-facing Components and Heat-sinks for Nuclear Fusion Reactors: Katherine Lee1; Brian Skinn1; Steve Snyder1; Maria Inman1; 1Faraday Technology, Inc.
The development of robust heat-sink and plasma-facing components (PFCs) suitable for high-heat flux applications is critical for the design of divertors in nuclear fusion reactors. For ITER-type divertor targets, which use tungsten PFCs and copper-alloy heat sinks, the extreme mismatch in the coefficient of thermal expansion (CTE) of these two materials has prevented them from reaching the performance metrics necessary for use in fusion reactors using conventional joining methods. Interlayers comprised of functionally-graded materials (FGMs) can overcome this mismatch by imparting gradual changes in CTE; however, selection of suitable fabrication methods for FGM relevant to fusion applications – such as Cu/WC composites and Fe/W alloys – remains a challenge. In this work, the feasibility of electrodeposition fabrication of FGMs suitable for use as CTE-matching interlayers is demonstrated and the ability to achieve compositional control during electroplating through the use of direct current, pulse, and pulse-reverse waveforms is evaluated.
3:50 PM
The Efficacy of Inorganic Zinc-Rich Primers to Mitigate Stress Corrosion Susceptibility in Al-Mg Alloys: Matthew McMahon1; Allison Akman1; Eric Dau2; 1Naval Surface Warfare Center, Carderock Division; 2Vision Point Systems, LLC.
Al-Mg alloys having 3-5 wt.% Mg content are common alloys used in marine structural applications that require light weight, high strength, and good weldability. Over long periods at 40ᵒC or more, however, the supersaturated Mg content causes sensitization in service, which causes increased susceptibility to intergranular stress corrosion cracking (IG-SCC). Previous work has demonstrated that cathodic protection via Zn-rich primers is selectively effective towards mitigating IG-SCC, however more work is needed before such a solution can be utilized in marine service. The present work evaluates a wide range of high-performing Zn-rich primers through use of the galvanostatic pulse test and accelerated stress corrosion cracking evaluations to understand key coating properties needed for optimal performance. The achieved efficacy of IG-SCC mitigation is compared to coating mechanical properties and ease of application to inform ease of use and likelihood of success in aggressive marine service conditions.