Soldering terminology

Halogens are considered essential components of solder flux. Even if no chlorides are used, bromides or fluorides are still in use. Since halogens are not completely used up during soldering, they may be present in the flux residue. Specific olefin compounds, which bind the halogens, may be added to the fluxing agent in order to remove halogens completely (see figure). Because these substances deactivate the halogens contained in flux residues, they are referred to as deactivators. Data suggests that the use of deactivators reduces halogen content from 1.0% of the solids content prior to soldering to only 0.04% after soldering. (Onishi & Takemoto: Materials Associated with soldering, 11th Research Conference on Microjoining, Japan Welding Society, p. 39-42.)