Amanda Napier, MSE, at NASA Kennedy Space Center

National Aeronautics and Space Administration

Kennedy Space Center , Florida

Corrosion Technology Laboratory, KT-E

Amanda Napier

Materials Science & Engineering

Summer 2007 - Co-op Tour 4

Graduated Lafayette High School, Lexington , KY

A note to middle and high school students:

"In high school I was a music major at the School for the Creative and Performing Arts, and although I was considered good at math and science I had no real interest in them. During my senior year I did five academic internships through the Experience Based Career Education (EBCE) program, and my time shadowing a chemical engineer actually caused me to set my track in the Materials Science program at UK . I couldn't be happier with that decision, and let's just say my high school friends are shocked when they learn that I've worked for NASA for 13 months. Engineering may seem daunting or even boring if you think "Ugh, math and science..." as I once did, but the wide open opportunity for challenging, exciting, creative work is truly its distinguishing quality."

My first project this summer focused on the sintering properties of four minerals known to be found in lunar soil (feldspar, spodumene, olivine, and ilmenite) as well as a mixture of all four. This general investigation served as a preliminary step in the "brainstorming" phase of finding and developing a resourceful method for constructing a lunar landing pad. Figure 1 shows the minerals in their original powder form before sintering.

Figure 1 . Raw minerals known to exist in lunar regolith.

Equal amounts of these minerals were manually compacted into crucibles and were sintered at 1000 degrees Celsius in a muffle furnace for 2 hours. The resulting "compacts" are shown in Figure 2.

Figure 2 . Minerals after sintering at 1000°C for 2 hours.

The feldspar and spodumene did not sinter at all, while the olivine underwent a color change and formed an extremely loose compact that broke apart easily upon removal from the crucible. The ilmenite formed a strong compact, while the mix of all four minerals formed an even stronger compact. The "edge" in the photo of the mix compact is actually part of the crucible that remains stuck to the bottom as it shattered upon several removal attempts.

I spent the bulk of my summer working with the new scanning electrochemical microscope recently purchased by my lab. As no one in my group has used it yet, my job was to perform experiments until I obtained one "realistic and useful" piece of data. Realistic data was easy to obtain using the gold specimen that came along with the demo of the instrument, however, useful data was another matter.

Scanning electrochemical microscopy is used to map the surface of a metallic specimen using the current produced by mediator reactions at the probe tip. (For the purposes of this report, I will spare the lecture on all the details and simply show my results.) Bulk aluminum often contains copper inclusions which will selectively corrode away and weaken the material. Cerium is a known corrosion inhibitor that will form a protective oxide layer on copper under basic conditions. To simulate such an instance on a macroscopic scale, I wound aluminum wire in a spiral around the end of a copper wire so that they were electrically coupled together. After finally finding a mediator that worked, ferrocenemethanol, I was able to perform cyclic voltammetry and approach curve experiments on bulk aluminum and copper substrates as well as the wound aluminum-copper specimen.

I was then able to perform area scans on the simulated aluminum-copper specimen before and after the addition of cerium into the solution. Before the cerium addition, the copper was conductive while the aluminum and polymer mold were insulation. Figure 3 shows the wound aluminum-copper specimen before the cerium addition.

Figure 3 . Area scan of aluminum-copper sample.

I then added a small amount of cerium to the solution and after waiting for a period of time performed another area scan over the same area. Figure 4 shows the resulting area scan in which the copper has become insulting.

Figure 4 . Area scan of aluminum-copper sample with cerium addition.

To determine if these SECM results were true, I had electron dispersive spectroscopy (EDS) performed on the specimen via the scanning electron microscope (SEM). The resulting EDS maps are showing in Figure 5. Figure 5a. is the SEM image of the specimen area, while 5b. indicates carbon in the area where the polymer was present, 5c. shows the aluminum part of the specimen, 5d. faintly shows some copper, and 5e. indicates a strong presence of cerium on the surface of the copper.

Figure 5 . EDS maps of aluminum-copper specimen;

electron image, b. carbon, c. aluminum, d. copper, e. cerium.

These results concluded that the SECM results were correct and therefore not only realistic but useful. Upon repeating the same experiment, I obtained the same results. My group can now consider this new instrument operational and ready for use with lab research.

Throughout the course of my four co-op terms, my responsibilities have increased along with my knowledge and confidence to perform the tasks at hand. This co-op term was different from the last in that my project was to prove a brand new instrument operational as opposed to working on a more research oriented project. Given that the summer is a much shorter term than my summer-fall co-op last year, this project fit well within the time frame. Both types of work were challenging and interesting.

Two classes that I took in the semester before I returned to work were very beneficial to me - my Corrosion elective was extremely useful as I do work in the Corrosion Technology Laboratory and the electrochemical analysis I performed relied heavily on the basic knowledge I gained from that course. The COM 181 course required of engineering students also drastically improved my public speaking skills. When I gave my final presentation my supervisors and coworkers were much impressed, and their feedback indicated that the course had been beneficial to me.

My typical work days still involve a mix of lab and office time. I have noticed that the days where I spend nearly all my time in the lab are not my favorites, so I am now more confident in the career and educational path I intend to take upon graduating with my BS. I do plan to return to KSC full time if possible and take graduate courses to earn a Master's degree in Engineering Management. My co-op has shown me that while I do enjoy some lab work and research, I am not driven to get my PhD in MSE at the present time and would be better suited in a path that involves both science and business.

In closing, I will provide some details about general life in this area. Living in Florida is not cheap. My rent and utilities this summer were roughly 35% of my income, and gas and food on top of that didn't leave me very much to play around with (although I never really found myself hard pressed for money to do anything I really wanted to do). This summer I lived in Orlando instead of at the beach as there is a lot more going on for the younger crowd and I was in close proximity to the University of Central Florida . The drive to work is about an hour from there, so gas would have been terrible had it not been for the vanpool I joined. I paid $4/day to ride a van with up to 10 other people to and from work.

As always, I enjoyed my time with NASA and in Florida . I watched my fifth shuttle launch while working at a guest viewing spot on the NASA causeway, I took a tour inside the orbiter Discovery, and saw Atlantis piggy-backing on a Boeing 747 fly over my head. I doubt work gets much more exciting than this, and I can't wait to get back.