Laser Surface Texturing of Ytterbium Disilicate to Improve Adhesion; Impact of anti-Asian racism in the United States on the development of technology 4 views

My STS project concerns the impact of anti-Asian racism in the United States on the development of technology. The research question investigated in this project is: “How has the presence of anti-Asian racism in the United States affected the development of technology?”. The methodology involved to answer this research question involved qualitative analysis of various literatures related to anti-Asian racism and technology. The first section of this paper covers the emergence of “prediction science” along with the growing feelings of Japanese “unpredictability” in Japanese internment camps in 1942. The second section explores the interplay between law and logistics in the history of global semiconductor production, and it focuses on anti-Asian legislation in the United States. The third section covers how the rhetoric of an ‘AI arms race’ between the United States and China has become increasingly prominent despite being unnecessarily polarizing. The United States desire to be a global economic-political hegemony through the alienation of Asians has altered how social media functions, constricted the advancement of semiconductors, and undermined the safe development of AI. These histories of anti-Asian racism and rhetoric being integrated in technological history indicates how Asian racism is at the roots of modern-day technology. My Capstone project concerned laser surface texturing of ytterbium disilicate to improve adhesion. The life of environmental barrier coating (EBC) systems can be limited by the growth rate of thermally grown oxide (TGO) and degradation from CMAS (calcia-magnesia-alumino silicate), which comes in the form of molten siliceous debris such as sand or dust. A single or multi-layer dense ceramic coating can be incorporated into the EBC system in order to improve the hermeticity and CMAS resistance. Different ceramic coating methods such as chemical vapor deposition (CVD), physical vapor deposition (PVD), sol-gel, and slurry can be used to achieve the needed density and eliminate the typical defects associated with a thermal spray coating. Even though these coating methods produce a dense coating, the thicknesses are limited to less than 100 µm and the surface roughness can be extremely low. Due to the low roughness, applications of additional coating layers to increase thickness result in spallation of the added layers due to lack of adhesion. As such, dense coatings manufactured by the methods specified enough cannot be used to achieve “thick” multi-layered coatings for applications that need it to achieve performance requirements. Laser surface texturing is posed as a potential method so that additional layers can be applied and then adhered. Laser surface micro-texturing can be employed to create surface roughness and features that promote the mechanical interlocking and bonding between coating layers. The first goal of this project was to determine how surface texture variables influence adhesion between EBC layers. The second goal of this project was to determine if a heat treatment could be utilized to improve the adhesion between two layers of ceramic coatings. The third goal was to determine if laser surface texturing induces changes in coating chemistry/microstructure. To do this, we selected three texture patterns applied at PulseTex using ultrashort-pulsed lasering, and we investigated their impact on composition and microstructure. We also applied a first heat treatment (HT1) prior to texturing to select samples and a second heat treatment (HT2) after the second coating was applied. We performed adhesion texting using an extensometer. Using a specified analysis framework we found that texture B (HT1, HT2) group performed significantly better than the untextured control group. EDS conducted on the top of the initial YbDS coating layer resulted statistically significant differences, but no other conclusions could be made. EDS conducted on the top of the initial YbDS coating layer revealed statistically significant compositional differences between textured and nontextured samples. Definitive conclusions regarding the effects of HT1 and HT2 could not be fully established due to variability amongst samples.

BS (Bachelor of Science)

Anti-asian racism; Japanese; Technology; Ceramic coating; Ultra-pulsed lasering; Digital

School of Engineering and Applied Science Bachelor of Science in Materials Science & Engineering Technical Advisor: James Fitz-Gerald STS Advisor: Karina Ripley Technical Team Members: Andrea Watson, Finley Pettitt, Joey Giordano, Michael Hann, Aaron Sweeney

English

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2026-05-11