2
Corrosion Research Grand Challenges
This chapter presents the committee’s thoughts about grand challenges for the broad field of corrosion science. The committee developed a working definition of a corrosion grand challenge, applied that definition to guide the identification of specific corrosion grand challenges, and then explored ways to prioritize these grand challenges. The results of the three steps—definition, identification, and prioritization—are presented in this chapter. Chapter 3 then describes representative samples of leading-edge research opportunities within each corrosion grand challenge area.
It is clear that this committee is not the first to have thought about grand challenges. Various agencies and organizations have used different approaches to the development of grand challenges, some of which are outlined in Box 2.1.
DISCOVERING THE CORROSION GRAND CHALLENGES
For the purposes of this study, the committee established the following as the criteria that a corrosion research grand challenge must meet:
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The corrosion research problem is demonstrably difficult to solve.
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The problem involves something that was not solved in the past, but may prove to be readily solvable if modern techniques are applied to the research.
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The problem requires significant contributions from multiple scientific disciplines.
BOX 2.1 Examples of Other Grand Challenges and Their Uses In March 2009 the National Academy of Engineering organized a grand challenge summit that defined a list of 14 leading engineering challenges for the 21st century.1 These grand challenges encompassed broad areas of human concern—sustainability, health, vulnerability, and joy of living—and encouraged the technical community to forge a better future by addressing the challenge areas. Although “corrosion” was not specifically mentioned in the resulting report, a case can be made that corrosion does affect each of the above four areas of human concern.2 The high-performance computing (HPC) community has effectively used grand challenge problems to define and focus resources on accomplishing “really difficult” tasks.3 The HPC grand challenges have been in the vanguard of the supercomputing revolution. Another example is evident in the grand challenges developed by the computational astrophysics community to stimulate interchanges among computational astrophysicists and applied mathematicians. A result has been identification of current barriers to algorithmic efficiency and accuracy, which has motivated a search for creative ways to surmount those barriers, or to decisively demonstrate that certain limitations are unavoidable.4 The National Science and Technology Council sponsored the report Grand Challenges for Disaster Reduction,5 which provided a framework for prioritizing federal investments in science and technology with the goal of reducing the impact of disasters. If met, the resulting six grand challenges targeting America’s capacity to prevent and recover from disasters would enhance the safety and economic well-being of the country. The American Association of State Highway and Transportation Officials adopted the grand strategy approach to identify seven high-level critical problem areas for bridge engineering that, if solved, would lead to significant advances in bridge design and reduced life-cycle costs. The resultant study Grand Challenges: A Strategic Plan for Bridge Engineering6 included a grand challenge, “extending service life,” that highlighted the need for improved corrosion-resistant materials and coatings, and improved corrosion-mitigation methods. The Department of Energy’s Basic Energy Sciences organization has consistently used the grand challenge approach to identify difficult science problems across a range of basic research areas.7
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The focus is on mitigation and prevention of detrimental corrosion processes, as opposed to beneficial applications of corrosion processes.1
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The solution will have a significant economic and/or social impact or overcome obstacles to desirable key technology required by society such as clean water and abundant environmentally benign energy.
The committee then considered two main approaches to developing a set of corrosion grand challenges:
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Hierarchical (top-down), starting with an overarching context for a grand challenge. For example:
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Formulate a set of societal grand challenges, and then identify corrosion research grand challenges that support these societal challenges.
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Identify major barriers to engineering accomplishments caused by corrosion.2
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Technological (bottom-up), developing grand challenges based on difficult technical problems. For example:
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Identify the critical gaps in understanding of the various forms of corrosion, and select those that might have the most far-reaching or transformative consequences. This mechanistic approach could be divided between classical aqueous metallic corrosion, corrosion issues related to non-metallic materials, and non-aqueous metallic corrosion such as high-temperature gaseous oxidation.
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Determine how recent fundamental breakthroughs in the underlying enabling science might be used to solve corrosion problems that have long been considered unsolvable, or applied to advanced materials subject to extreme environments.
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The committee decided to combine the hierarchical and technological approaches (see Figure 2.1). First, it identified the top national priorities or goals, which are the far-reaching societal demands that trigger future technology advancements. The committee then linked those drivers to the various U.S. federal agencies with missions in each of those areas. Applying its members’ knowledge of gaps in knowledge of corrosion, the committee identified key areas for corrosion research and correlated them with the societal drivers to formulate a list of challenges for
future research.3 Finally, the committee aggregated and generalized the list of challenges to avoid narrowing the range of corrosion problems. The result was a small set of corrosion grand challenges.
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This approach was similar to that taken by the Department of Transportation in developing decision-making strategies for the future: a set of external forces and trends were identified and cross-matched with a set of research focus areas; see “Long Range Strategic Issues Facing the Transportation Industry—Final Research Plan Framework,” prepared for National Cooperative Highway Research Program Project 20-80, Task 2, by ICF International, October 17, 2008, available at http://onlinepubs.trb.org/onlinepubs/archive/NotesDocs/NCHRP20-80(2)_FR.pdf. |
LINKING TECHNICAL GRAND CHALLENGES TO SOCIETAL NEEDS
Top-level priorities for federal investment are contained within each federal agency’s strategic plan, budget requests to Congress, presidential speeches, congressional hearings, and so on. It is these high-level national priorities that guided the committee in its identification of overarching societal priorities for protection against and mitigation of corrosion. The top national priorities were categorized as infrastructure, health and safety, energy, environment, national security, and education.4
The federal agencies and departments associated with these national priorities have distinct roles in corrosion research, as outlined in Figure 2.2. Additional details are given in Appendix E.
In broad terms, the issues in corrosion science and engineering can be subdivided into four key areas for research and development:
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Design (materials modeling tools),
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Mitigation (corrosion protection and maintenance methods, corrosion modeling tools and databases, design rules, lessons learned),
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Detection (corrosion damage assessment), and
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Prediction (life extension, prognosis).
Following the approach to analysis depicted in Figure 2.1, the committee considered critical gaps in current understanding of corrosion science that affect each of the societal drivers for the four key corrosion research areas. The committee developed a set of 11 representative corrosion challenges (Table 2.1) that, although not intended to be a comprehensive compilation of all the important challenges in corrosion research and development, does reveal many connections to the societal drivers. When coupled with Figure 2.2, the information in Table 2.1 suggests the relevance of corrosion research challenges to the intended goals of federal agencies with missions in these societal areas.
CORROSION GRAND CHALLENGES
The list of 11 challenges in Table 2.1 was sufficiently comprehensive to allow the next step of analysis—identifying the corrosion grand challenges. With the challenge “constructive uses of corrosion” eliminated as not applicable to materials
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These are essentially the same priorities as those identified in National Research Council, Assessment of Corrosion Education, The National Academies Press, Washington, D.C., 2009, available at http://www.nap.edu/catalog.php?record_id=12560. |
TABLE 2.1 Matrix of Challenges and Societal Drivers That Lead to Corrosion Research Opportunities
Challenges |
Infrastructure |
Health and Safety |
Energy |
Environment |
National Security |
Education |
Cost-effective corrosion- and stress corrosion/hydrogen embrittlement-resistant materials |
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Environmentally friendly materials, coatings, and inhibitors |
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Understanding the nature of protective films and scales, including structure |
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Complete and comprehensive understanding of electrochemistry and other interfaces from the electronic to the microscale level |
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Lifetime modeling and prediction, design for specific corrosion properties, quantitative environmental corrosion intensity factor |
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Advanced coatings, including long-lasting paint and functional coatings |
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Science of accelerated testing; quantitative assessment technique for corrosion rate in “difficult” electrolytes |
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Product and reaction pathways in systems with multiple environmental stresses |
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Constructive uses of corrosion (synthesis, mechanistic understanding of functional processes) |
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Effects of stress and cracking |
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Prognosis—sensors, detection, remote monitoring |
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degradation, Table 2.2 indicates how the 10 remaining challenges were grouped by the committee to yield four corrosion grand challenges (CGCs):
CGC I—Development of cost-effective, environment-friendly corrosion-resistant materials and coatings;
CGC II—High-fidelity modeling for the prediction of corrosion degradation in actual service environments;
CGC III—Accelerated corrosion testing under controlled laboratory conditions that quantitatively correlates to observed long-term behavior in service environments; and
CGC IV—Accurate forecasting of remaining service time until major repair, replacement, or overhaul becomes necessary—i.e., corrosion prognosis.
TABLE 2.2 Correlation of Corrosion Challenges to Corrosion Grand Challenges
Challenge |
Key Area for R&D |
Grand Challenge |
Cost-effective corrosion- and stress corrosion/hydrogen embrittlement-resistant materials |
Design, Mitigation |
CGC I Development of cost-effective, environmentally friendly corrosion-resistant materials and coatings |
Environmentally friendly materials, coatings, and inhibitors |
Design |
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Advanced coatings, including long-lasting paint and functional coatings |
Design |
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Understanding the nature of protective films and scales, including structure |
Prediction |
CGC II High-fidelity modeling for the prediction of corrosion degradation in actual service environments |
Complete and comprehensive understanding of electrochemistry and other interfaces from the electronic to the microscale level |
Prediction |
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Lifetime modeling and prediction, design for specific corrosion properties, quantitative environmental corrosion intensity factor |
Prediction, Mitigation |
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Product and reaction pathways in systems with multiple environmental stresses |
Prediction |
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Effects of stress and cracking |
Prediction |
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Science of accelerated testing; quantitative assessment technique for corrosion rate in “difficult” electrolytes |
Prediction |
CGC III Accelerated corrosion testing under controlled laboratory conditions that quantitatively correlates to observed long-term behavior in service environments |
Prognosis—sensors, detection, remote monitoring |
Detection, Prediction |
CGC IV Accurate forecasting of remaining service time until major repair, replacement, or overhaul becomes necessary—i.e., corrosion prognosis |
The four CGCs developed by the committee represent engineering, science, and technology challenges deemed to incorporate the drivers and guiding principles of a framework for prioritizing research and development activities. However, the committee strongly notes that addressing these challenges will demand an integrated body of cross-disciplinary and interdisciplinary scientific and engineering research targeted at specific needs and coordinated to minimize duplication and to take advantage of synergism.
As depicted in Figure 2.3—a hierarchical representation of the four corrosion grand challenges, supported, as they must be, by the body of corrosion science and engineering research—the ultimate proactive challenge is the development of materials that resist corrosion for a given application (CGC I). The remaining three corrosion grand challenges effectively address the design and in-service life cycle of functional components: (a) CGC II leads to the development of modeling tools and databases that will allow calculation of the degree of corrosion attack and the effort required to reduce its impact, for a particular application given the material of interest, sufficient knowledge of the anticipated corrosion environment, and the different corrosion processes of concern. This capability will allow quantitative consideration of the life-cycle costs for different design solutions during the acquisition phase of a system that will be subject to corrosive environments. (b) CGC III attacks the thorny issue of extrapolating, with high fidelity, expected field performance based on laboratory-scale testing. The crux of the challenge is that there is a large mismatch between the time available for laboratory testing,
typically on the order of months, and the time that a structural or functional component will be in service, typically many years. Therefore, laboratory testing must be accelerated, requiring significant knowledge of the underlying corrosion mechanisms and the expected corrosive environment, including temporal variations in key environmental parameters. (c) CGC IV addresses the critical need to monitor the actual deterioration of a component once it is placed in service in a corrosive environment and then provide a reasonable forecast of the remaining time before a maintenance or replacement action is required.
Underlying all these applied issues is a strong need to resolve basic mechanistic issues that are barriers to progress in CGCs I through IV. The committee felt that addressing these mechanistic issues is essential to reducing gaps in understanding. Also essential is the dissemination of the fundamental information that will enable other grand challenges to be addressed.
ADDRESSING THE GRAND CHALLENGES: A NATIONAL CORROSION STRATEGY
Each of the four corrosion grand challenges (see Figure 2.3) addresses important societal needs. The committee recognizes that each federal agency and department must establish its own priorities for investing in corrosion research, depending on the nature and relevance of corrosion damage with respect to their individual missions and their underlying science and technology capabilities. Their diverse responsibilities may include funding and performing research as well as leveraging what is already known about corrosion control and mitigation to reduce the cost of corrosion for their mission applications. Accordingly, the committee recommends that each agency and department utilize the corrosion grand challenges proposed here and the underlying research opportunities as a framework for prioritization, based on expected benefits for its mission, and using methodologies consistent with an appropriate plan for allocating resources. Furthermore, the committee encourages development of a process that involves industry and professional and scientific societies to facilitate rapid dissemination of results. Examples are shown in Box 2.2.
The corrosion research opportunities presented in Chapter 3 of this report support the corrosion grand challenges presented above. In prioritizing these research opportunities, various factors should be taken into account, including expected societal value, degree of scientific difficulty, and the time required to attain a meaningful benefit. (See Box 2.2 for some examples.) Societal impact can be measured in different ways, such as the magnitude of the potential problem or the probability (or frequency) of its occurrence. Some corrosion problems might be solved fairly readily, and priorities could be established by identifying which research avenues are likely to yield the greatest or most rapid payoff, as measured
BOX 2.2 Examples of Corrosion Challenges and Societal Needs Challenge: Cost-effective corrosion-resistant materials Societal Driver: Energy Need: Lack of cost-effective materials leads to high energy costs, including inability to fully develop energy resources. Example: Deep offshore oil and gas wells—current piping materials suitable for harsh corrosion environments are quite expensive and can account for an appreciable fraction of the cost of developing these resources. Also, some oil and gas fields are not economical to develop as a result. Research Opportunity: Surface modification of lower-cost materials to impart required corrosion resistance, and use of fundamental materials understanding and combinatorial methods to develop new corrosion-resistant alloys that are inherently less expensive to manufacture and field Challenge: Remote detection and monitoring of corrosion Societal Driver: Safety Need: Manage aging infrastructure structures that suffer from corrosive degradation. Example: Dams and bridges (highway and railroad) Research Opportunity: Development of highly durable, accurate corrosion sensors suitable for remote application; development and validation of algorithms that use sensor information to determine extent of life degradation and predict when maintenance actions will be necessary Challenge: Cutting by half the cost of materials for energy systems Societal Driver: Energy Need: Lack of cost-effective materials leads to high energy costs, including inability to fully develop energy resources. Example: Solar concentrating technologies such as parabolic dish, trough, and Scheffler reflectors can provide process heat for commercial and industrial applications. However, the reflectors need to retain their surface properties and not corrode. Research Opportunity: New production methods to produce coatings that can protect the surface of reflectors for solar concentrating technologies Challenge: Improving the safety of the built infrastructure by 10 percent Societal Driver: Safety Need: Manage aging infrastructure that suffers from corrosive degradation. Example: As infrastructure is built or rehabilitated, life-cycle cost analysis should be performed for all infrastructure systems to account for initial construction, operation, maintenance, environmental, safety, and other costs reasonably anticipated during the life of the project. Research Opportunity: Algorithms to better predict costs of maintenance and protection against corrosion of infrastructure, which could enable effective up-front decisions about, for example, materials selection |
Challenge: Advanced coatings, including long-lasting paints and functional coatings Societal Driver: Safety Need: Lack of cost-effective materials creates maintenance problems leading to safety problems. Example: Bridge paint is often incorrectly applied or incorrectly chosen, causing many corrosion problems, especially in areas not open to direct human inspection; underperforming corrosion-protective paint was part of the Minneapolis I-35W Bridge failure in 2007 Research Opportunity: New polymers; new application methods; new inspection methods; new coating materials (pigments, inhibitors); improved durability in the face of exposure to ultraviolet radiation Challenge: Environmentally friendly inhibitors Societal Driver: National security Need: For environmental and health reasons, future military systems may be required to eliminate use of chromate inhibitors and heavy-metal coatings. Use of composite structures (e.g., polymer composites that contain carbon fibers) can exacerbate the corrosion attack of contacting metals. Example: Advanced fighter aircraft utilize advanced carbon-reinforced composites in contact with metallic structural elements. Research Opportunity: Design of environmentally benign barrier coatings using fundamental understanding of materials science and mechanisms of active corrosion |
by the potential return on investment or savings, increased safety, or enhanced quality of life. Alternatively, priorities could be based on selecting research that is expected to be the most transformative and far-reaching.
To tackle the full range of research opportunities that address societal needs, a robust research portfolio must contain a balance of programs that provide both incremental benefits and large, transformative benefits. The matrix in Figure 2.4 shows one strategy that a federal agency could use in building a balanced corrosion research portfolio and indicates examples of research projects in each quadrant.
Recommendation: Using as guidance the four corrosion grand challenges developed by the committee, each federal agency or department should identify the areas of corrosion research pertinent to its mission and draw up a road map for fulfilling its related responsibilities. In doing so, each should take a cross-organizational approach to planning and execution and should include input from industrial sectors that have experience in handling corrosion.
For most federal agencies, with the exception of DOD and NASA, the committee was unable to discern a coherent, integrated top-level corrosion strategy or roadmap. In general, federal agencies play multiple roles by which they could influence the corrosion community and supporting industries: as purchasers of equipment and facilities, as sponsors of scientific research and engineering developmental work, as developers and enforcers of regulations and standards, and as sources of best-practice information for use by state governments, industries, and small businesses. For agencies that do not have a strategic plan, corrosion research appears fragmented, and funding is allocated without considering the full impact on agency activities. While each agency and department must play a role consistent with its own mission, isolated government programs can lead to duplicative efforts, reduced opportunities for synergistic progress, and difficulty in focusing interdisciplinary research teams on addressing large-impact research opportunities.
To address such issues and to establish its proposed national corrosion strategy as a multi-agency effort that must be aimed at maximizing societal benefit, the committee emphasizes the need for cross-agency coordination and policy oversight.
Recommendation: The Office of Science and Technology Policy (OSTP) should acknowledge the adverse impact of corrosion on the nation and launch a multi-agency effort for high-risk, high-reward research to mitigate this impact. OSTP should set up a multiagency committee on the environmental degradation of materials. It should begin by documenting current federal expenditures on corrosion research and mitigation and then encouraging multiagency attention to issues of research, mitigation, and information dissemination. Collaboration among departments and agencies should be strengthened by collaboration with state governments, professional societies, industry consortia, and standards-making bodies.