Fusão, refinamento e extrusão de vidros compostos para aplicações em fibras opticas

AUTOR(ES)
DATA DE PUBLICAÇÃO

1987

RESUMO

Using induction furnace to glass melting is one of the purest methods, because the glass is melted directly, removing, for example, the contamination caused by refractories. In this work we will show the raw materials preparation and the characteristics that envolve the compound glasses melting in na induction furnace (RF) , specifying the kind of initial heating used for mullite and quartz crucibles. During the melting, it is necessary to remove the bubbles that remain inside the melted glass. We had tested the following three methods: (a) vacuum, (b) gas bubbling, (c) accelerated crucible. These methods present a great efficiency, and (a) and (b) are better, as we will see in details in this work. For practical reasons, the selected method was He bubbling. Besides, the glass melting and refinement experiences, we had made a preliminary study related to the sliding mechanisms that the glasses suffer during extrusion. This method can be used to rods and tubes production, that will serve to fiber optics to short distances fabrication by the method rod-in-tube. Three basic different glasses compositions were tested: A = 70% B2O3 + 30% PbO; B = 37,3% B2O3 + 42,3% SiO2 + 19,4% Na2O + 1% Al2O3; C = 34,25% PbO + 25,04% P2O5 + 23,91% Nb2O5 + 16,80% K2O (% em mo1) . We will see that the glass flow is explained by the "Channel adhesion" mechanism, and B and C glasses are explained by the "sliding film" mechanism. During the extrusion, we will also observe "flow anomalies" that are caused by glass viscosity variety due to "shear stress" that the glass suffer when flows through the "die" channel

ASSUNTO(S)

fibras oticas vidro

ACESSO AO ARTIGO

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