Transformation of cuprite to tenorite through a martensitic-like type process in copper-doped glasses annealed in reduced atmosphere with the metal copper formation

Abstract

The incorporation of copper nanoparticles into the glass matrix has attracted great interest in many fields due to their significant physical and chemical properties and their applications (e.g. opto-electronic and bio-medical tools). Several methodologies, such as the doping method and subsequent annealing of the glass in oxidizing and reducing atmospheres to synthesize copper nanoparticles in a glass are widely used. In this work, the doping method and subsequent annealing of the glass in a Ar/H2 atmosphere has been used. This treatment caused a martensitic-type transformation which, to our knowledge, has not been mentioned in the literature. The result was the transformation from cuprite to tenorite about 300°C, and the presence of dispersed rounded and polyhedral copper nanoparticles and dendritic shapes of nanoparticles. The reaction of CuO and H2, between 250 and 300°C, originated metallic copper particles. The mechanism of the martensitic-type transformation has been derived from the characterization results of copper-doped glasses annealed in reduced atmosphere by optical microscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. The martensitic-like type structure could have imparted shape memory characteristics to the copper-doped glasses annealed in reduced atmosphere, opening a window for future research.