Transient Metal Alloy Oxidation Kinetics Visualized by In situ UHV-TEM

Judith C. Yang, University of Pittsburgh, DMR 0706171

GOAL: Fundamental understanding of the complex nano-scale oxidation kinetics and energetics of metal alloys by using in situ ultra high vacuum transmission electron microscope (UHV-TEM); this research bridges the gap between surface science and bulk oxidation studies.

METHOD: We are currently studying CuxNi1-x as a model binary alloy system to gain insights into selective oxidation behavior. Cu and Ni are 100% solid-soluble down to ~300 °C but Cu2O and NiO show very limited miscibility.

IMPACT: Advanced coating materials contain multiple elements to form a protective,slow-growing, thermodynamically stable oxide. This research will provide critical knowledge into the important parameters (surfaces, surfactants, strain, environmental conditions) that control selective oxidation and possibly a new paradigm of metal oxidation.

In situ oxidation of Cu (100) at T= 1000°C, pO2 = 5 X 10-4 Torr

In situ oxidation of Cu-15 at%Au (100) at T= 600°C, pO2 = 5 X 10-4 Torr

In situ oxidation of Cu-2.4 at% Ni (100) and Cu-13.6 at% Ni (100) at T= 600°C, pO2 = 5 X 10-4 Torr

Only cube-on-cube oxide islands formed on Cu(100) surface

Dendritic structured oxide islands formed on Cu-15%Au (100) surface

Epitaxial oxide islands and secondary nucleation of small oxide particles formed on Cu-Ni (100) surface

Transient Metal Alloy Oxidation Kinetics Visualized by In situ UHV-TEM

Judith C. Yang, University of Pittsburgh, DMR 0706171

Research Experience:

Graduate Education:

This grant provides the support for one female graduate student:

Ms. Zhuoqun Li (01/08-present)

High School Outreach:

Figure: 2nd annual PJAS and PECAP “Visualization of Nanotechnololgy” workshop. U. Pittsburgh. 10/11/08

The PI participates in the annual Pennsylvania Junior Academy of Science (PJAS) workshop where local high school students visit the the Nanofacility at U. Pittsburgh for hands-on demonstrations for a day, including electron microscopy. The recent PJAS includes Pitt Engineering Career Access Program (PECAP) students. PECAP is a U. Pittsburgh program to recruit, retain and graduate students from under-represented groups in STEM fields.

Undergraduate Research Experience:

This grant provides the support three undergraduate student (one female) for summer research and senior design project:

Ms. Katherine D. Rodger (5/09-present) Mr. Malay D. Shah (5/09-present) Mr. Steve Ziemak (5/08-5/09)

Malay D. Shah, Katherine D. Rodger and Zhuoqun Li (Left to right)