Galvanizing Flux and Soldering

Most metal surfaces develop scale, rust, and oxides when they are exposed to air, and heating speeds up this process. These pollutants are to be removed to make solder adhere to or wet the metal. During the soldering process, chemical compounds like flux are used to clean and maintain metal surfaces. Fluxes help solder become a better wetting agent with a decrease in surface tension.

Fluxes are available in the forms of paste, cake, liquid, or powder. They are classified into noncorrosive and corrosive. Corrosive fluxes provide the most efficient metal surface cleaning action. Any trace of corrosive flux left on the work can cause later corrosion. In this sense, corrosive fluxes are not employed on electrical connections due to corrosion, which causes a serious problem.

In metallurgy, flux chemically cleans the metals to be joined that are used in soldering, welding, and brazing. The primary purpose of flux is to prevent surface oxidation in high-temperature metal joining processes such as welding, soldering, and brazing.

Zinc chloride has three basic uses as a flux on metal surfaces.

• Removal of oxides
• Promote wetting
• Prevents re-oxidation of the surfaces during heating.

Zinc chloride (corrosive flux) acts as a reducing agent to remove oxides from the surface of metals. It also helps in cleaning the surface of metals with other impurities or deposits. If metal surfaces are oxidized, good solder contact cannot be obtained. Molten solder can easily wet and sticks onto the oxide-free iron and zinc metal surfaces upon cooling.

Zinc chloride provides surface protection by preventing the subsequent entry of oxygen onto the surface. Additionally, it prevents heated surfaces from re-oxidation, which could otherwise quickly get oxidized. It also allows solder to flow easily on the working piece and avoid bead formation.

Zinc chloride is used in soldering galvanized Iron, Tin sheet, Brass, and other Zinc surfaces.