Sn-Zn-Ga-Ce leadless brazing filler metal

Abstract

The invention relates to Sn-Zn-Ga-Ce lead-free brazing filler metal, which belongs to a metal material and a braze welding material of the metallurgic field. The chemical constitution according to a mass percentage is as follows: 5 to 10 percent of zinc, 0.05 to 3 percent of gallium, 0.001 to 0.5 percent of cerium, 0.01 to 3 percent of silver, 0.001 to 0.5 percent of aluminum, and rest percent of tin. Market sold tin ingot, zinc ingot metal, gallium, silver ingot (or silver plate), aluminum ingot and metal cerium are in a mixture ratio according to requirements; when smelting, optimization screened and determined covering agentia is added or inactive gas protection is adopted for smelting and casting, so as to get a bar. Through extruding and drawing, the brazing filler metal silk material is gained (scaling powder can also be added so as to make flux-cored brace welding wire). With the adoption of a powder manufacturing apparatus, new brazing filler metal can be made to a graininess (the graininess size is between 0.106 mm (140 mu) to 0.0380 mm (400 mu)) so as to be used for BGA packaging or made to the soldering paste for use.

Description

1. Technical field [0001] The invention relates to a green and environment-friendly lead-free solder alloy for component welding and surface assembly in the field of microelectronic packaging, especially a new type of Sn-Zn- The Ga-Ce lead-free solder belongs to metal materials and brazing materials in the field of metallurgy. 2. Background technology [0002] At present, the lead-free solders researched and developed at home and abroad mainly include high-temperature Sn-Ag, Sn-Ag-Cu, Sn-Cu, Sn-Sb, medium-temperature Sn-Zn and low-temperature Sn-Bi, Sn- In alloys, which are widely used at this stage mainly include Sn-Ag-Cu for reflow soldering and Sn-Cu for wave soldering. However, the cost of Sn-Ag-Cu solder is relatively high, while Sn-Cu has a relatively high melting point, which requires high requirements for components and welding equipment. The Sn-Zn series lead-free solder materials have a wide range of sources, low price and cost, good mechanical properties, and si...

AI Technical Summary

Problems solved by technology

However, the cost of Sn-Ag-Cu solder is relatively high, while the melting point of Sn-Cu is relatively high, which requires high requirements for components and welding equipment.

The Sn-Zn series lead-free solder materials have a wide range of sources, low price and cost, good mechanical properties, and similar melting point to Sn-Pb eutectic solder. Solder, however, due to the active chemical properties of Zn, usually Sn-Zn lead-free solder is easy to oxidize, which not only leads to the loss of solder due to oxidation, but also the oxidized slag formed on the surface makes Sn-Zn solder originally poor. The wettability is worse, which restricts the popularization and application of this system of solder

In recent years, ternary alloys and multi-component alloys such as Sn-Zn-In, Sn-Zn-Al, Sn-Zn-Bi, Sn-Zn-Ag have been developed on the basis of Sn-Zn at home and abroad, and binary Sn-Zn Compared with these alloys, alloys have improved in some properties, but in terms of overall performance, they are still not as good as traditional Sn-Pb solder and Sn-Ag-Cu solder which is widely used now. Therefore, the new Sn-Zn solder Still needs further research

Images