Halide, halide-oxide, and oxide fluxes are commonly used in various chemical and metallurgical processes, including soldering, brazing, and metal casting. Here's a general overview of how these fluxes are prepared:
Halide Fluxes: Halide fluxes are typically prepared by dissolving metal halides (such as chlorides, bromides, or fluorides) in an appropriate solvent. The solvent can be water or an organic solvent depending on the specific flux requirements. The metal halides used in the flux depend on the desired application and the metals involved. For example, zinc chloride (ZnCl2) or ammonium chloride (NH4Cl) are commonly used as halide fluxes in soldering processes.
Halide-Oxide Fluxes: Halide-oxide fluxes combine the properties of both halide and oxide fluxes. They are prepared by mixing metal halides and metal oxides. The specific metal halides and metal oxides used depend on the application and the metals involved. For instance, a common halide-oxide flux used in aluminum brazing contains a mixture of aluminum chloride (AlCl3) and aluminum oxide (Al2O3). The ratio of halide to oxide components can be adjusted based on the desired reactivity and melting characteristics of the flux.
Oxide Fluxes: Oxide fluxes are prepared by combining metal oxides with suitable binders or carriers. The metal oxides used in these fluxes vary depending on the application and the metals being processed. Some commonly used metal oxides include boron oxide (B2O3), zinc oxide (ZnO), and phosphorous pentoxide (P2O5). The metal oxides are often mixed with organic binders or solvents to form a paste or powder flux. The binder or carrier helps adhere the flux to the metal surfaces during the process.
It's important to note that the specific preparation methods and compositions of fluxes can vary based on the intended application and the desired properties of the flux. Different flux formulations are optimized for specific processes, temperatures, and materials being worked with.