Grey leaf shaped objects against a dull copper background.
Leaves in the backyard
was created by the idea that I would like to connect the black and white world of scanning electron microscopy (SEM) images with more vivid and relatable objects. Objects that can easily represent our daily life, such as the falling leaves in everybody’s backyard in the fall.

This SEM image was captured on a copper surface after it was corroded in an aqueous solution containing sodium chloride and sodium sulfide. To be more specific, this image was acquired at an accelerating voltage of 1 kV to minimize the decomposition of copper sulfide species since they may decompose under exposure to the high-energy primary electron beam when imaging the surface using SEM.  As shown in the SEM image, the “leaves” occupy most of the examined surface, representing the morphology of copper sulfide formed on copper under these particular experimental conditions. Buried under the “leaves” are the small platelet-like features, which are also distributed uniformly across the copper surface.  When looking at this image, I was astonished by the beauty of the fine features (≤ 1 μm) and how vividly it reminded me of the nature of corrosion. Additionally, in the view of art, there is a subtle connection between inorganic species (copper sulfide) and the organic creature (leaves).

This particular scientific research was funded by the Nuclear Waste Management Organization (NWMO) and the Swedish Nuclear Fuel and Waste Management Organization (SKB) during my PhD studies at the department of chemistry,  Western University, under the supervision of Dr. Dave Shoesmith and Dr. Jamie Noël.  This research was conducted to assist in the understanding of the corrosion/degradation behavior of copper-coated used nuclear fuel containers. Copper acts as the corrosion barrier and has been chosen for the fabrication of used nuclear fuel containers due to its stability under the oxygen-free and cool conditions anticipated in deep geologic repositories for the permanent disposal of the high-level nuclear waste.  As of June 2019, Canadian nuclear reactors had produced 2.9 million spent fuel bundles, which is equivalent to around 52,000 tonnes of high-level waste.  Hence, it is of vital importance to study the degradation mechanism of copper under the simulated repository conditions and apply knowledge obtained from current research to safely encapsulating these nuclear wastes using the proposed waste containers in fulfilling a million-year disposal plan.

Lastly, I would like to acknowledge both my PhD supervisors, Dr. Dave Shoesmith and Dr. Jamie Noël, for their endless support and encouragement during my PhD study. In addition, special thanks goes to Dr. Jian Chen and Dr. Todd W. Simpson, who assisted me in preparing my corrosion experiments and using SEM at Western nanofabrication facility, respectively.