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Smart Coatings for Autonomous Corrosion Detection and Control

Corrosion is the degradation of a material that results from its interaction with the environment. The environment at the Kennedy Space Center’s (KSC) Beachside Atmospheric Exposure Test Site near the launch pads have been documented by ASM International (formerly American Society for Metals) as the most corrosive in the United States. The 70 tons of highly corrosive hydrochloric acid that are generated by the solid rocket boosters during a launch exacerbate the natural corrosiveness of the coastal environment at the pads. Numerous failures at the pads are caused by corrosion of stainless steels, rebar corrosion, and the degradation of refractory concrete. Corrosion control of launch pad structures relies on the use of coatings and materials that can withstand the marine atmosphere as well as the launch conditions. Coatings are selected from the qualified products list (QPL) of the NASA Standard 5008A for Protective Coating of Carbon Steel, Stainless Steel, and Aluminum on Launch Structures, Facilities, and Ground Support Equipment. This standard was developed to establish uniform engineering practices and methods and to ensure the inclusion of essential criteria in the coating of ground support equipment (GSE) and facilities used by or for NASA. This standard is applicable to GSE and facilities that support space vehicle or payload programs or projects and to critical facilities at all NASA locations worldwide. In recent years, environmental regulation changes have dramatically reduced the availability of conventional corrosion protective coatings. Current attrition rate of qualified KSC coatings will drastically limit the number of commercial off the shelf (COTS) products available for future ground operations in support of launch operations at KSC. For this reason, corrosion detection and control technologies have been identified as a critical, initial capability technology need for ground processing of future launch vehicles, reduced ground processing complexity, streamlined integrated testing, and operations phase affordability and sustainability. Researchers at NASA’s Corrosion Technology Laboratory at KSC are developing a smart, environmentally friendly coating system for early corrosion detection, inhibition, and self healing of mechanical damage without external intervention. This coating is being developed using corrosion sensitive microcapsules and particles designed to deliver corrosion indicators, corrosion inhibitors, and self healing agents on demand when corrosion or mechanical damage to the coating occurs. This paper presents the results from progress made to date in developing a coating for the smart corrosion control of launch pad structures and GSC.

Environmentally friendly corrosion preventive compounds for ground support structures

The need to use environmentally friendly technologies throughout future space-related launch programs prompted a study aimed at replacing current petroleum and solvent-based corrosion preventive compounds (CPCs) with environmentally friendly alternatives. The work in this paper focused on the identification and evaluation of environmentally friendly CPCs for use in protecting flight hardware and ground support equipment from atmospheric corrosion. CPCs are used as temporary protective coatings and must survive in the aggressive coastal marine environment that exists throughout the Kennedy Space Center, Florida. The different protection behaviors of fifteen different oily film CPCs, both common petroleum-based and newer environmentally friendly types, were evaluated on various steel and aluminum substrates. CPC and substrate systems were subjected to atmospheric testing at the Kennedy Space Centers Beachside Atmospheric Corrosion Test Site, as well as cyclic accelerated corrosion testing. Each CPC also underwent physical characterization and launch-related compatibility testing. The results for the fifteen CPC systems are presented in this paper.

Refractory Materials for Flame Deflector Protection

Fondu Fyre (FF) is currently the only refractory material qualified for use in the flame trench at KSCs Shuttle Launch Pads 39A and 3913. However, the material is not used as it was qualified and has undergone increasingly frequent and severe degradation due to the launch blasts. This degradation is costly as well as dangerous for launch infrastructure, crew and vehicle. The launch environment at KSC is unique. The refractory material is subject to the normal seacoast environment, is completely saturated with water before launch, and is subjected to vibrations and aggressive heat/blast conditions during launch. This report presents results comparing two alternate materials, Ultra-Tek FS gun mix and Kruzite GR Plus, with Fondu Fyre. The materials were subjected to bulk density, porosity, compression strength, modulus of rupture and thermal shock tests. In addition, test specimens were exposed to conditions meant to simulate the launch environment at KSC to help better understand how the materials will perform once installed.

Predicting the Long-Term Field Performance of Coating Systems on Steel Using a Rapid Electrochemical Test: The Damage Tolerance Test

Abstract The pace of coatings development is limited by the time required to assess their corrosion protection properties. This study takes a step forward from past studies and correlates the corrosion performance of protective coatings assessed by a series of short-term electrochemical measurements with 18 month and 60 month beachside atmospheric exposure results of coated panels. A series of 11 coating systems on A36 steel (UNS K02600) substrates were tested in a blind study using the damage tolerance test (DTT). In the DTT, a through-film pinhole defect is created, and the electrochemical characteristics of the defect are then monitored over the next 1 to 7 days while immersed in 0.5 M sodium chloride (NaCl). The results from open-circuit potential, anodic potentiostatic polarization, and electrochemical impedance spectroscopy tests were used to characterize the corrosion behavior of the coating systems. The beachside exposure tests were conducted at the Kennedy Space Center (Kennedy Space Center, Flor...

Launch Pad Coatings for Smart Corrosion Control

Corrosion is the degradation of a material as a result of its interaction with the environment. The environment at the KSC launch pads has been documented by ASM International (formerly American Society for Metals) as the most corrosive in the US. The 70 tons of highly corrosive hydrochloric acid that are generated by the solid rocket boosters during a launch exacerbate the corrosiveness of the environment at the pads. Numerous failures at the pads are caused by the pitting of stainless steels, rebar corrosion, and the degradation of concrete. Corrosion control of launch pad structures relies on the use of coatings selected from the qualified products list (QPL) of the NASA Standard 5008A for Protective Coating of Carbon Steel, Stainless Steel, and Aluminum on Launch Structures, Facilities, and Ground Support Equipment. This standard was developed to establish uniform engineering practices and methods and to ensure the inclusion of essential criteria in the coating of ground support equipment (GSE) and facilities used by or for NASA. This standard is applicable to GSE and facilities that support space vehicle or payload programs or projects and to critical facilities at all NASA locations worldwide. Environmental regulation changes have dramatically reduced the production, handling, use, and availability of conventional protective coatings for application to KSC launch structures and ground support equipment. Current attrition rate of qualified KSC coatings will drastically limit the number of commercial off the shelf (COTS) products available for the Constellation Program (CxP) ground operations (GO). CxP GO identified corrosion detection and control technologies as a critical, initial capability technology need for ground processing of Ares I and Ares V to meet Constellation Architecture Requirements Document (CARD) CxP 70000 operability requirements for reduced ground processing complexity, streamlined integrated testing, and operations phase affordability. Researchers at NASAs Corrosion Technology Laboratory at KSC are developing a smart, environmentally friendly coating system for early corrosion detection, inhibition, and self healing of mechanical damage without external intervention. This smart coating will detect and respond actively to corrosion and mechanical damage such as abrasion and scratches, in a functional and predictable manner, and will be capable of adapting its properties dynamically. This coating is being developed using corrosion sensitive microcapsules that deliver the contents of their core (corrosion inhibiting compounds, corrosion indicators, and self healing agents) on demand when corrosion or mechanical damage to the coating occurs.

Electrochemical Evaluation of Alloys for Spaceport Design

Corrosion studies began at the Kennedy Space Center (KSC) in 1966 during the Gemini/Apollo Programs with the evaluation of long‐term protective coatings for the corrosion protection of carbon steel. NASA’s KSC Beach Corrosion Test Site, which was established at that time, has been documented by the American Society of Materials (ASM) as one of the most corrosive naturally occurring environments in the world. With the introduction of the Space Shuttle in 1981, the already highly corrosive conditions at the launch pad were rendered even more severe by the acidic exhaust from the solid rocker boosters. In the years that followed, numerous studies have identified materials, coatings, and maintenance procedures for launch hardware and equipment exposed to the highly corrosive environment at the launch pad. The Corrosion Laboratory was established at KSC in 1985 and was outfitted with state‐of‐the‐art electrochemistry equipment to conduct research and materials characterization in many different corrosive envir...