1994 Volume 12 Issue 4 Pages 485-494
This experiment, the behavior of Cadmium (Cd) during brazing, reports the cases of fumes, flux and filler metal in case of using BAg-1 BAg-3. And at the same time the authors observed the floating fumes during brazing by EPMA, farthermore they examind number frequency (%) about particle size of fumes, and were made clear particle size (μm) distribution of fumes.
This experiment was conducted to clarify the behavior of Cd on brazing more correctly and completely so as to obtain a guideline for executing more proper brazing and for finding the safety measures.
As a result, the following conclusion was obtained :
(1) The amount of Cd content in flux (slag), compared with that in fumes, was approx. 300 up the 700 times when brazing was done at the optimum heating temperature, it was reduced to approx. 3 up to 30 times, due to increasing movement of Cd content to fumes, when the optimum temperature was exceeded. The result suggests the necessity of an effective consideration to be given to flux cleaning.
(2) Of fumes, flux and filler metal, filler metal is the largest in terms of Cd percentage by weight. It was clarified however that flux contained 10-1 or so of Cd even at the optimum heating temperature and that both fumes and flux contained 10-1 up the 1 of Cd when the optimum heating temperature was exceeded.
(3) Particle size of fumes signify same tendency regardless of heating temperature. Number fre-quency is the most highest below fume size 0.43, um, and this phenomenon means that these fume size are generally very fine. Also, up about 95% are below 7.07, um fume size which are absorbed fumes, and so we must be careful of the fumes which are produced in case of using filler metals containing Cd.