Papers by Author: Ramiro Pérez

Abstract: Mechanical milled powders of boron nitride were obtained. The microstructural characterization of these milled powders was carried out using X-ray diffraction technique. Insights on the nature of the crystalline phases obtained in these milled powders were obtained between comparisons of theoretical and experimental X-ray diffraction patterns. Observations on the phase transformations have been carried out using calorimetry and thermogravity experiments. Morphological and microstructural characteristics of nanocrystals are obtained using SEM and HRTEM instruments.

Abstract: The microstructure of FeAl40 intermetallic alloy produced by spray atomization and deposition, with boron additions and reinforced with Al2O3 particles was studied. This technique allowed the co-deposition of particulate reinforcement and the addition of boron in order to obtain a boron concentration of 0.4 at. %. The additions of alumina particles produce a grain refinement. High resolution transmission electron microscopy observations shows a precipitation of boron in the FeAl matrix in despite of the rapid solidification process. Fe3B precipitates were found which is a metastable phase formed during the rapid solidification process. In addition, FeB precipitates were observed.