Sample records for copper base alloys
from WorldWideScience.org

Sample records 1 - 2 shown.



1

Desenvolvimento de um dispositivo para obtenção de monocristais de ligas à base de cobre/ Development of a device for obtaining single crystals of copper-based alloys

Blanco, Matildes; Barelli, Nilso; Benedetti, Assis Vicente; Flor, Samuel Waldemar Andrade
2003-10-01

Resumo em inglês This paper describes the drawing, construction and optimization of a device, which can be used to obtain single crystals of different metallic materials with melting point from 550 to 1050 ºC. Components of ease obtaining and of low cost were used. The device was based on the modified Bridgman technique and it was used to obtain single crystals of copper-based alloys. The temperature axial profiles and a difference less then 1% in the temperature between the wall and the (mais) center of the ceramic tube in the critical region for obtaining single crystals of good quality indicated that the oven presents a good thermal stability. Single crystals of CuZnAl and CuAlAg alloys of good quality were growth and characterized using optical microscopy and Laüe X-ray back reflection.

Scientific Electronic Library Online (Portuguese)

2

O Escurecimento do Altar da Sé do Porto: Um Caso de Corrosão Atmosférica/ The Tarnishing of the Silver Altar of Porto’s Cathedral: An Atmospheric Corrosion Case

Homem, Paula M.; Fonseca, Inês T. E.; Cavalheiro, José T.
2008-09-01

Resumo em português O objecto deste estudo, o Retábulo da Sé do Porto, foi caracterizado através da análise morfológica e microanalítica de amostras recolhidas em diferentes zonas do Retábulo, correspondentes às várias fases de construção. Concluiu-se que as ligas usadas na construção do Retábulo são ligas de prata:cobre com percentagens em Ag entre 62,59% e 97,98%, esta correspondente ao elemento mais importante do conjunto, o primeiro a ser construído, o sacrário. No que r (mais) espeita aos produtos de corrosão, com base na análise feita por espectroscopia de difracção de raios-X (EDX), foi possível postular a existência de compostos de prata, tipo cloretos, e de cobre, tipo, óxidos e sulfatos. Foram ainda identificados sulfatos de sódio e de potássio e aluminosilicatos, além de vestígios dos produtos de limpeza. Resumo em inglês Samples taken from the different zones of the silver altar of Porto’s Cathedral were characterized by morphological and analytical techniques. It was concluded that the material used in the altar piece was Ag:Cu alloys with Ag ranging between 62.9 % and 97.8 %. Concerning to the corrosion products it was possible to postulate the existence of silver compounds, as chlorides, and copper compounds, as oxides and sulphates. Other products identified related with the environment were the sodium and potassium sulphates and aluminosilicates, apart from some cleaning residues.

Scientific Electronic Library Online (Portuguese)