RAYANNE REINALDO - Academia.edu (original) (raw)

Papers by RAYANNE REINALDO

Anais do X Congresso Nacional de Engenharia Mecânica, 2018

Ceramics International, 2021

Abstract In the present work, Al2O3-10 wt% Fe composite powders were manufactured by mechanical a... more Abstract In the present work, Al2O3-10 wt% Fe composite powders were manufactured by mechanical alloy using different milling times. The morphology, structure and magnetic properties were carefully investigated and explained through the results of SEM, XRD (with Rietveld refinement), Mossbauer spectroscopy and magnetic measurements at low-temperatures. After 50 h of milling, the results reveal α-Fe particles uniformly distributed in Al2O3 and a decrease of the average particle size of Al2O3–Fe composite. Besides, XRD data show a decrease of crystallite sizes, accompanied by an increase of the lattice micro-strain. For samples milled for 30 h and 50 h, the Mossbauer spectra recorded at 300 K showed a superparamagnetic component related to very fine hematite crystallites with a maximum absorption relative area of 10%. The M − H curves recorded at 6 K showed a small reduction in saturation magnetization, and an improvement in remanence magnetization and coercivity field with milling time, while the M-T curve of the sample milled for 50 h shows a peak at 185 K, related to the Morin transition of the hematite phase.

International Journal of Refractory Metals and Hard Materials, 2020

A mixture of Cu-20wt%WC was milled in a high energy mill for up to 50 h. The WC powder was recycl... more A mixture of Cu-20wt%WC was milled in a high energy mill for up to 50 h. The WC powder was recycled from hard metal scrap. It presents agglomerates of faceted WC particles and residual Co and Fe. In the first hours of milling, the Cu particles are deformed into plates, the agglomerates of WC are broken apart, the primary WC particles are fragmented and embedded in the Cu phase. Composite particles are formed. As milling proceeds, different plates are welded together and folded. The particle size increases. However, the hardened Cu becomes fragile and begin to break, decreasing the particle size. Both, Cu and WC are under compressive strain. Residual Co and Fe present in the recycled powder are dissolved in Cu and behave like the soft Cu phase.

Modo de acesso: World Wide Web Inclui bibliografia 1. Petróleo 2. Combustíveis. I. Andrade, Davil... more Modo de acesso: World Wide Web Inclui bibliografia 1. Petróleo 2. Combustíveis. I. Andrade, Davilson Eduardo CDD338.2728 O conteúdo dos artigos e seus dados em sua forma, correção e confiabilidade são de responsabilidade exclusiva dos seus respectivos autores.

Anais do X Congresso Nacional de Engenharia Mecânica, 2018

Ceramics International, 2021

Abstract In the present work, Al2O3-10 wt% Fe composite powders were manufactured by mechanical a... more Abstract In the present work, Al2O3-10 wt% Fe composite powders were manufactured by mechanical alloy using different milling times. The morphology, structure and magnetic properties were carefully investigated and explained through the results of SEM, XRD (with Rietveld refinement), Mossbauer spectroscopy and magnetic measurements at low-temperatures. After 50 h of milling, the results reveal α-Fe particles uniformly distributed in Al2O3 and a decrease of the average particle size of Al2O3–Fe composite. Besides, XRD data show a decrease of crystallite sizes, accompanied by an increase of the lattice micro-strain. For samples milled for 30 h and 50 h, the Mossbauer spectra recorded at 300 K showed a superparamagnetic component related to very fine hematite crystallites with a maximum absorption relative area of 10%. The M − H curves recorded at 6 K showed a small reduction in saturation magnetization, and an improvement in remanence magnetization and coercivity field with milling time, while the M-T curve of the sample milled for 50 h shows a peak at 185 K, related to the Morin transition of the hematite phase.

International Journal of Refractory Metals and Hard Materials, 2020

A mixture of Cu-20wt%WC was milled in a high energy mill for up to 50 h. The WC powder was recycl... more A mixture of Cu-20wt%WC was milled in a high energy mill for up to 50 h. The WC powder was recycled from hard metal scrap. It presents agglomerates of faceted WC particles and residual Co and Fe. In the first hours of milling, the Cu particles are deformed into plates, the agglomerates of WC are broken apart, the primary WC particles are fragmented and embedded in the Cu phase. Composite particles are formed. As milling proceeds, different plates are welded together and folded. The particle size increases. However, the hardened Cu becomes fragile and begin to break, decreasing the particle size. Both, Cu and WC are under compressive strain. Residual Co and Fe present in the recycled powder are dissolved in Cu and behave like the soft Cu phase.

Modo de acesso: World Wide Web Inclui bibliografia 1. Petróleo 2. Combustíveis. I. Andrade, Davil... more Modo de acesso: World Wide Web Inclui bibliografia 1. Petróleo 2. Combustíveis. I. Andrade, Davilson Eduardo CDD338.2728 O conteúdo dos artigos e seus dados em sua forma, correção e confiabilidade são de responsabilidade exclusiva dos seus respectivos autores.