Abstract
The oxidation and drossing characteristics of molten solders are especially important in the high-production mass-soldering processes used in industry. A reduction in loss of solder as dross has become increasingly desirable from an economic viewpoint but there is a lack of information on methods of achieving this. The oxidation results reported in this paper were achieved by using a method which simulates one form of agitation occurring in a mass-soldering machine. The simulation was effected in the laboratory by stirring the surface of a small bath of solder in such a manner that the rotating stirrer continuously disrupted the layers of oxide to produce dross. The effects on oxidation of temperature, time, stirring rate, and the ratio of tin/lead in the solder were investigated. Several drosses were analysed. In order to comment on a possible correlation with oxidation data for static surfaces, several solder alloys were oxidized in a thermobalance. An addition of about 10% of tin to molten lead reduced oxidation to a minimum under standard stirring conditions. Drosses were found to contain 90–95% by weight of unoxidized solder despite their powdery appearance.
Get full access to this article
View all access options for this article.