Abstract
Raw materials are the foundation of all technologies. They are the often unseen building blocks of everything that we use and interact with daily. Critical minerals are one such raw material that have received increased attention in recent years due to their global importance and supply chain threats. Rare earth elements (REEs) are critical minerals that are used in a wide variety of technologies but are especially critical for several green technologies. In my engineering capstone, I have worked with aerospace RE oxide coatings that are used in jet engines. While green technologies and jet engines appear dissimilar, they both depend on REEs; this piqued my curiosity about the intersection of these two technologies, which arises at the very beginning of the manufacturing process: mining. Rather than centering my research paper on REE criticality and supply chain issues, I have chosen to focus on the upstream effects of REE mining on communities. Understanding how REEs are sourced is critical to understanding the full global impacts of the technologies that we use, help produce, and interact with throughout our lives.
Aircraft engines are complex systems that are exposed to a variety of extreme environments during operation. As an engine operates, corrosive media is ingested which can find its way into extremely high temperature areas, creating a highly corrosive environment. Environmental barrier coatings (EBCs) have been developed as a protective layer between the underlying material and the harsh engine environment. Rolls-Royce uses ytterbium disilicate, a RE oxide, as the EBC to protect SiC engine components. Current coating techniques used to apply the EBC impose thickness limitations which are not improved by layering the coatings, as it leads to spallation during operation. In my technical capstone, my team is laser surface texturing the interface between two EBC coating layers to determine if mechanical interlocking and adhesion strength is improved. Assessing the viability of this new technique is critical to advancing the aerospace industry and ensuring that engines are as efficient as possible while being safe and dependable.
Transitioning the global economy to one that depends on green technologies rather than fossil fuels is essential for limiting global warming and preventing devastating climate change. However, implementing more of these clean innovations does not come without a cost. REEs are used in a wide array of technologies, highly valued for their chemical uniqueness; they are specifically desirable for use in technologies like wind turbines and electric vehicles. REEs must be mined before incorporating them into products; these mines are incredibly destructive not only to the surrounding environment and the health of mining communities, but also to the social dynamics within them. Often, these mines further entrench existing problems and hinder growth and improvement. My research will focus on understanding the struggles that mining communities face and investigating proposed solutions to these problems. In understanding the mining communities and the ways in which they have been affected by REE mines, I will propose a brighter path forward that involves efforts from both governments and mining corporations.
This engineering thesis has given me a broader perspective on the global supply chain, and I have learned to be more cognizant of the underlying impacts of major technologies, especially those that are touted as clean energy breakthroughs and landmarks on the path to a better future. Throughout my career I will continue to be aware of the ethicality of material sourcing and I will continue to ask myself the question: who falls behind as the rest of the world progresses?
