Water-solubility dip coating tin scaling powder and preparation thereof

Abstract

The invention relates to a water soluble thermal leaching tin plating flux and a preparing method thereof. The components and the weight proportions of the flux are as follows: 5 to 10 percent of oxidization film removing agent; 5 to 15 percent of copper-tin ion complexing agent; 0.01 to 5 percent of surfactant; the rest of solvent. Compared with the prior art, the flux has the advantages of excellent chemical activity, good wettability, avoiding wicking substrate and good oxidation susceptibility of solder material.

Description

Water-soluble hot-dip tin-plating flux and preparation method thereof technical field The invention relates to a flux used in the hot-dip tinning process of a metal substrate, in particular to a water-soluble hot-dip tinning flux and a preparation method thereof. Background technique One of the ways to realize the solderability and oxidation resistance of the outer leads of glass-encapsulated diodes and other electronic products is hot-dip tinning. The hot-dip tinning process requires the use of flux to improve soldering quality. The function of the flux is mainly chemical reaction, it must be able to react with the metal oxide film and generate a flux-soluble compound, and at the same time prevent oxidation, reduce surface tension, and improve the wettability of solder to the surface of the substrate. When using the lead-tin plating process, the temperature of the tin furnace is only about 260°C, and there is lead at the same time, the melting point is low, the surface i...

AI Technical Summary

Problems solved by technology

Now the RoHS environmental protection system has strict restrictions on the content of heavy metals such as lead, and it is no longer possible to add lead and other environmentally harmful substances to solder, so lead-containing substances cannot be used in hot-dip tin plating

At the same time, due to lead-free solder, the melting temperature of soldering is greatly increased, and the tin furnace is severely oxidized in the air, which will cause the solder material in the soldering furnace to oxidize and produce a large amount of oxidized tin slag. The use of ordinary flux can no longer meet the process requirements. , it will seriously deteriorate the soldering conditions, so that the surface of the hot-dip tin layer is rough, or even hot-dip tin-plated, which is prone to produce more "tips", the height of the tin dipping is not enough, the solder layer is not full, not smooth, and the solder layer Easy to darken and other bad phenomena

In patent 00112453.6, substances such as hydrazine hydrate and hydrazine are used as the reducing atmosphere and protective atmosphere of hot-dip tinning, but hydrazine hydrate is carcinogenic, and must be pickled with 9% hydrochloric acid before dipping flux, which increases the process