A pulse oxidation facility for the study of oxide nucleation behavior

Area of Science:

• Materials Science
• Surface Science
• Oxidation Kinetics

Background:

• Understanding initial oxidation behavior is crucial for material durability.
• Oxide nucleation and growth are influenced by temperature, oxygen partial pressure, and substrate crystallography.
• Previous studies often lacked precise control over initial oxidation conditions and substrate orientation.

Purpose of the Study:

• To develop and validate a pulse oxidation experimental facility for studying oxide nucleation.
• To investigate the influence of crystallographic orientation on oxide nucleation and growth behavior.
• To explore oxidation kinetics under controlled, short-duration, high-temperature conditions.

Main Methods:

• Development of a pulse oxidation facility with electromagnetic induction heating, controlled oxygen atmosphere (1.3 × 10⁻⁵ to 0.1 Pa), and temperature control up to 1200 °C.
• Utilizing single grain-orientation-mapped Ni-30%Cr samples for controlled oxidation experiments.
• Analyzing oxide island nucleation density and growth morphology on grains of known crystallographic orientation (e.g., (111) and (100)).

Main Results:

• Demonstrated the facility's capability to study oxidation at 600 °C for 45 s at 1.3 × 10⁻² Pa.
• Observed distinct oxide island formation: corundum on (111) grains (2.9 × 10¹¹ islands/m², inward growth) and rock salt on (100) grains (7 × 10¹² islands/m², outward growth).
• Characterized oxide island sizes: corundum (50-300 nm) and rock salt (50-600 nm).

Conclusions:

• The developed pulse oxidation facility enables precise investigation of initial oxidation phenomena on bulk samples.
• Crystallographic orientation profoundly affects oxide nucleation density and growth mechanisms.
• This study opens new avenues for understanding oxidation under realistic exposure conditions.