Method for preparing gold-tin alloy foil

Abstract

The invention discloses a method for preparing a gold-tin alloy foil. The method comprises the following steps of: 1, pressing a gold-tin laminated body to obtain a composite blank; 2, putting the composite blank into a corundum crucible of a vacuum induction furnace to be heated till the composite blank is completely melted, keeping heating, filling the vacuum induction furnace with argon till positive pressure is formed in the vacuum induction furnace, and moving the corundum crucible in the direction away from an induction heating area at a constant speed till materials in the corundum crucible are solidified into a cast ingot; 3, after heat preservation is carried out on the cast ingot, carrying out rolling to obtain a roughly-rolled foil; 4, rolling the roughly-rolled foil to obtain a finish-rolled foil; 5, under an oil bath condition, carrying out annealing treatment on the foil obtained after finish rolling in the step 4 to obtain an annealed foil; and 6, polishing, trimming and cleaning the foil annealed in the step 5 to obtain a finished foil. According to the method disclosed by the invention, the quality of the cast ingot can be improved, meanwhile, annealing before rolling and intermediate annealing links are omitted, the production efficiency is high and the production cost is low.

Description

technical field [0001] The invention belongs to the technical field of material preparation, and in particular relates to a method for preparing gold-tin alloy foil. Background technique [0002] The melting point of AuSn20 alloy is 280°C, and its brazing temperature is generally 300-330°C. The alloy has high strength at room temperature and high temperature, and can work in high temperature environments or environments with large temperature changes. The alloy has good corrosion resistance and good corrosion resistance. Wettability and excellent thermal and electrical conductivity are widely used in optoelectronic packaging, high-reliability electronic and electrical hermetic packaging and chip packaging. Solder. However, the plastic deformation ability of AuSn20 alloy is poor, and it is difficult to process it by conventional methods. At present, the preparation methods of gold-tin alloy foil include laminated composite method, casting and rolling method and rapid solidi...

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Problems solved by technology

[0003] Patent CN1026394C and literature (Wei Xiaofeng. Preparation of AuSn20 eutectic solder for electronic packaging and its related basic research [D]. Changsha: Central South University, 2013.) adopt laminated composite method to prepare gold-tin solder foil, although this method avoids Solved the problem that the gold-tin solder is difficult to deform, but the welding effect is affected due to the inability to accurately control the content of different metals

Patent CN102912175B adopts casting and rolling method to prepare gold-tin solder foil. Firstly, graphite crucible is used to smelt and cast gold-tin ingot with fine-tuned composition, and then hot rolling method is used to obtain gold-tin solder foil with a thickness of 0.02-0.1mm. The existing problems include : The ingot is easy to oxidize during the smelting process, the ingot needs to be annealed for each pass in the hot rolling process, the production cost is high, the production efficiency is low, and the fine-tuning of the composition affects the welding performance of the alloy, etc.

Patent CN103753057B adopts the extrusion method to process gold-tin ingots into foils of different sizes. This process is simple, but the prepared foils are thick (≥0.3mm), which is difficult to meet market demand

Patents CN102114584B, CN103290251A and literature (Hu Zhebing. Au-20Sn solder strip preparation and interface structure research [D]. Wuhan: Huazhong University of Science and Technology, 2018.) A gold-tin sheet with uniform composition was prepared by a single-roller rapid solidification method , but the method is complex and the surface quality of the prepared strip is poor

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