Novel rubidium and cesium brazing flux

The invention provides a novel rubidium and cesium brazing flux and belongs to the field of brazing materials for non-metallic materials. The novel rubidium and cesium brazing flux comprise 0.12-0.5 mole of rubidium fluoride (RbF), 0.12-0.5 mole of cesium fluoride (CsF), 0.001-0.2 mole of aluminum oxide (Al2O3), 0.001-0.02 mole of lithium fluoride (LiF), 0.0001-0.02 mole of gallium oxide (Ga2O3) and the balance aluminum fluoride (AlF3). The novel rubidium and cesium brazing flux has the advantages that the brazing requirements of aluminum-copper, aluminum-steel and aluminum-aluminum can be met at the same time, and the activity is high.