Thermodynamic Study of the Mg-Ca-Zn system Shanae Henry Philadelphia, Pennsylvania, Sophomore,...
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Transcript of Thermodynamic Study of the Mg-Ca-Zn system Shanae Henry Philadelphia, Pennsylvania, Sophomore,...
Thermodynamic Study of the Mg-Ca-Zn system
Shanae HenryPhiladelphia, Pennsylvania, Sophomore, Lankenau High School
Hakeem JacksonPhiladelphia, Pennsylvania, Junior, Lankenau High School
Ryan RobinsonPhiladelphia, Pennsylvania, Senior, Lankenau High School
Presentation Outline:
• Introduction
• Background
• Methods
• Experiment
• Results
• Microstructural Analysis
What is Thermodynamics?
Thermodynamics is the study of Gibbs free energy.
• Gibbs free energy– G=H-TS
• Phase stability– Lowest Gibbs free
energy
www.humanthermodynamics.com
Objective
Purpose:
Perform a Diffusion Couple to validate the existence of the Ca2Mg5Zn13 that was predicted by previous researchers.
Hypothesis:
The predicted phase Ca2Mg5Zn13 exists [ is stable] at 335 and 160 degrees Celsius.
What is Diffusion?
Diffusion is the movement of molecules from an area of high concentration to an area of low concentration.
Materials Properties:
Magnesium
• Flexible
• Light Weight
Calcium:
• Rather soft
• Reacts with water
Zinc:
• Reasonable conductor of electricity
• Good corrosion resistance
Phase Transformation
•The process of one phase to another
•The rate at which a phase will become stable
•Also we can use Phase Transformations to see when two or more substances co-exist
Phase Diagram
• Graphical representation that shows the phases that are present
What can be seen by the phase diagram?• Number of phases present• Composition of each phase
Materials
• 70 wt% Mg-30 wt% Ca, pure Zn
• 600 Grit paper• Diffusion couple• Lathe Machine• Didymium Glasses• 335o Celsius furnace • 160o Celsius furnace• Vacuum
• Wet Saw Machine• Glass Tube• Fiber Glass• Epoxy Resin• Hardener• Liquid nitrogen• Oxygen• Gloves
Procedures
Step 1- Initial Polishing
Step 2- Make the Diffusion Couple
Step 3-Turn on each furnace to the destination temperatures [335 and 160 degrees Celsius]
Step 4-Place the samples inside each furnace for a period of two weeks
Step 5- Microstructural Analysis
Results
Due to lack of time there was not sufficient diffusion that took place.
As a result- we could not predict whether the phase existed or not, although the surfaces of our samples were clearly different.
Conclusion/ Future References
If scientists wish to conduct this experiment again then they should:
• Allow more time for diffusion
• Change the percentages of each metal
• Increase the temperature to decrease the time for diffusion
Acknowledgements
We will like to give special thanks to:• EMS Faculty: Professor Zi-Kui-Liu• EMS Graduate Students: Swetha Ganeshan,
and Hui Zhang• The College of Earth and Mineral Sciences• EMS Glass Maker: Doug Smith• UBMS Instructor: Mrs. Pam Monk• UBMS Director: Ms. Jody Markley• UBMS Assist. Director: Mrs. Annie Holmes• UBMS Staff