Discovering novel platinum structures

• Main Author: Mabunda, Khanyisa Prudence
• Other Authors: Lang, Candy
• Format: Dissertation
• Language: English
• Published: University of Cape Town 2015
• Subjects: Engineering
• Online Access: http://hdl.handle.net/11427/11747

Includes abstract. === Includes bibliographical references. === The Pt[8]Zr ordering transformation in Pt 11 at. % Zr alloys has been studied. The study included determination of the formation of the Pt[8]Zr phase and its order/disorder transformation temperature (Tc). Electron diffraction patterns and dark field images were obtained from transmission electron microscopy to characterize the Pt[8]Zr phase. Microhardness measurements and light microscopy were used to investigate the Pt[8]Zr ordered phase and its effects on hardness and microstructure respectively. The Pt[8]Zr ordered phase was found to be present in the initial as-cast condition and in specimens heat treated up to a temperature of 1070 °C. This is consistent with the DSC measurements of Tc, determined to be 1068 °C. The nucleation of the ordered phase was found to be rapid at any temperature below Tc but the growth of this ordered phase was rather slow, probably due to inadequate vacancies present in the alloy. The domain size of the Pt[8]Zr phase was found to be approximately 10 nm for specimens heat treated at 1000 °C for up to 600 hours.