Material and its preparation method and application of the multilayer of ladder silicone content without brazing flux

The invention discloses a kind of multilayers of ladder silicone content without material of brazing flux and its preparation method and application, the multilayer of the ladder silicone content is without the material of brazing flux, including successively compound sandwich layer, brazing layer and coating, brazing layer is different with the silicon mass content of coating.Coating and brazing layer of the present invention all contain silicon material, using the brazing layer concentration difference different with coating silicone content, flow soldering acid from high concentration to low concentration direction, effectively break through oxidation film.Highly concentrated Mg is also flowed with silicon material simultaneously, it is diffused near oxidation film, the magnesium diffused out is in the case where oxygen content is relatively low, magnesium occurs to generate point crystalline substance first with Process on Aluminum Alloy Oxidation Film, the sharp crystalline substance of generation, which is easy to be brazed liquid (silicon material), is rolled onto liquid internal, the soldering acid of welding is come into full contact with, along with capillary, the effects of profit is invaded, soldered fitting welding quality is made to reach saturation.Bi element is added in coating or brazing layer, so that it takes the lead in breaking through oxidation film.