Float reaction between sodium aluminoborosilicate glassmelts and copper-base liquid metal alloys

摘要

Wavelength-dispersive X-ray spectroscopy (WDS) has been utilized in a study of redox chemical diffusion dynamics in reaction couples of two sodium aluminoborosilicate glassmelts - both lightly doped with Fe3+ - with two copper-base liquid metal alloys: Cu-37 at.%Ge and Cu-36 at.%Sn. The glassmelts were floated on the alloys for 30 min in a controlled, reducing atmosphere at temperatures in the range 1200-1350 &DEG; C. Despite there being a significant driving potential to incorporate Cu+.2+ into the glassmelt, such does not occur: ionic Cu concentration in the glassmelts was below the detection limits of WDS (i.e., X-Cu < 100 ppm atomic). As a generalization, the Ge2+.4+ and Sn2+.4+ diffused into the glassmelt to a depth of &SIM; 50 μ m, a distance similar to that seen for ionic Sn in the soda-lime silicate on pure Sn float process that is operated at notably lower temperatures and for dramatically shorter reaction times. For reactions with Cu-37 at.%Ge, doping the glass with ferric iron had a profound effect on the depth of penetration Ge4+, a network of ionic Ge, decreasing it significantly: Fe3+ acts as an electron acceptor from Ge2+; the resultant tetravalent cation (Ge-4, a network former) is all-but immobile. A similar result was not seen for reactions with the Cu-Sn alloy, a consequence of considerable reduction of the glassmelt by its pre-reaction with molybdenum components of a delivery system. The reaction morphologies seen are consistent with the Wagner/Schmalzried formulation for dynamic redox reactions. © 2005 Elsevier B.V. All rights reserved.