DD228198A1 - METHOD FOR PRODUCING POWDER-FIRMING BASE SUBSTANCES FOR SOLIDS FROM AL-GE ALLOYS - Google Patents

Abstract

The invention relates to the field of metallurgy. The object of the invention is to create conditions for the production of Al-Ge alloys in powder form, which are suitable as basic substances for solders and in their use Loettemperaturen 500C are sufficient. The task of producing a low-oxide powder is solved when 45-58% by weight of Al and 42-55% by weight of Ge are melted, the melt is cooled by known rapid cooling methods at a rate of 105 Ks 1 and the resulting sproders short tape pieces are ground under O2 exclusion. Parts of the Al and / or Ge can be replaced by Ag. Objects which can be produced by the process according to the invention are powders which have an O 2 content of 0.5% by mass and can be used as base substances for paste-like solders or as solder preforms.

Description

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Process for the preparation of powdery basic substances for solders of Al-Ge alloys

Field of application of the invention

The invention relates to the field of metallurgy and relates to a method for producing powdered metallic base substances from the alloying elements

Al, Ge, and, if necessary, for .Lote.

With additives in paste form or pressed into soldering blanks, these solders are particularly advantageously suitable for joining surfaces coated with Al or Al alloys or surfaces coated with Ag or Ag alloys in automatable soldering processes.

The temperatures required for soldering are ^ 500 ^° C.

Characteristic of the known technical solutions

Process for the production of solder alloys in a compact. Porm from pure Al-Ge alloys are not known. "According to ÜS-PS 3 844 777 a process for the production of Al-Ge-Ag alloys for solders is known in which 13-16 mass $ & L, 38-47 Mass-Ge and 35-40 mass- # Ag melted under inert gas and placed in compact pieces suitable for soldering. The disadvantage of this method is that the solder produced in this way is only

,, is reversible when the surfaces to be soldered are pre-treated by consuming Be ₁ J.ζeir and the soldering is carried out under vacuum at temperatures of> 500 ⁰ C "

Furthermore, according to US-PS 3,697,259 a process for the production of Al-Ge-Si alloys is known, in which 35-55 mass # Al, 25- 6O mass $ Ge and 5-20 mass $ Si melted and be used in the form of compact pieces, wires or sheets for soldering. The shortcoming of the solder produced in this way is that the required soldering temperatures between 548 ⁰ C and 591 ⁰ C.

DD-WP 203 269 also discloses a process for the production of welding powders by comminuting alloys and pasting these powders with plastics into endless elastic strands.

Powder as a base substance for paste-like solders or to process as compacts brings the particular advantage mit.sich that before the shaping soldering surfactants, activators, wetting agents and the like "can be added and soldering processes can be carried out economically with these solders"

To date, it has failed to produce powders from the Al-Ge alloys, - that the powders produced by conventional methods, for example by atomizing the molten metal or crushing boards, have too high an oxygen content that they are used as metallic base substance makes it unsuitable for solders «

A further disadvantage of the previously known Al-Ge solder alloys is that the soldering temperatures in the alloy compositions used are> 5OO ⁰ C and thus the range of application is limited *

Object of the invention

The object of the invention is to create conditions for the production of Al-Ge alloys in powder form, which are suitable as basic substances for solders in paste form or as moldings and in the use of soldering temperatures ^ 500 ⁰ C are sufficient.

Explanation of the essence of the invention

The invention has for its object to provide a production method for low-oxide powder of Al-Ge alloys whose compositions allow soldering temperatures of <£ 500 ⁰ C «

According to the invention, this object is achieved in that alloys with 45-58 mass # Al and 42-55 mass # Ge are melted, the melt by per se known method of "tendon 11 he stung '(melt" spinning, melt extraction) at a speed> 10 ^7-10 Ha is cooled, "which briefly a multiphase microcrystalline band produced" but this is so brittle that it either already broken or the ejection of the cooling surface into short pieces easily crushable is "the pieces of tape are then under exclusion of air further processed into powder.

The powders produced in this way are well suited as a metallic base substance for pasty solders which can be applied to printed circuits by screen printing technology, and the piilver can easily be pressed into soldering blanks by moistening with pressing aids. These solders are particularly suitable for bonding surfaces coated with Al or Al alloys. «

In order to expand the field of application, in particular for connecting the surfaces coated with Ag or Ag alloys, it is expedient to use part of the Al and / or Ge by Ag

so that alloys are melted in which the alloying constituents are within a polygon in the ternary phase diagram Al-Ge-Ag whose vertices are from the points

A (45 mass% Al, 55 mass% Ge, O mass # Ag) B (58% Al, 42% Ge, 0% Ag)

C (37 ti al, 34 ti Ge, 29 » Ag) D (35 H al, 20 ti Ge, 45 η Ag) e (30 ti al, .18 ti , Ge, 52 It Ag) P (32 It al, 46 Il Ge, 22 , Il Ag)

be formed «

The soldering temperatures of the pure Al-Ge alloys and the Ag-containing Al-Ge alloys are between 450 and 500 ^° C. *

The invention will be explained in more detail below with reference to two exemplary embodiments.

Embodiment 1

An alloy with 55 »# 4 mass Al and 44.6 wt $ Ge is melted and the melt is printed at a temperature of 600 ⁰ C on a rapidly rotating cooling roll made of Al and at a speed Ϊ. 5 * 10 ^ Ks "* ¹ cooled by the high cooling rate and the pronounced brittleness of the alloy no coherent band, but short ca * 1 arises -. 10 cm long pieces of tape of 40 / m in thickness and 5 mm in width.

The comminution takes place in a double-walled tube vibrating mill, the spaces between which are filled with liquid nitrogen. After 30 minutes, a flake-form metal powder having an average particle size of 60 μm is formed. The O ₂ content is 0.3 mass #.

Execution game 2

An alloy containing 33 mass # Al, 45 mass # Ge and 22 mass # of Ag is melted and printed at a temperature of ⁰ C 6OO onto a rapidly rotating cooling roll of chromium plated copper und.mit a rate of> 1 · Ks ICK cooled. The resulting ca * 10 cm long pieces of tape of 35 / um thickness and 5 mm in width are used in a vibrating mill with purging of inert gas, N ₂ , 10 min is ground. The resulting metal powder has an average particle size of 50 μm, the O ₂ content is 0.2% by mass.

Claims (2)

invention claim 1 * Process for the preparation of powdery basic substances for solders of Al-Ge alloys, characterized in that alloys with 45-58 mass # • Al and 42-55 mass $ Ge are melted, the melt by known methods of rapid cooling with cooled to a speed of> 1Cr - 10 ITs "and the resulting pieces of tape are ground under exclusion of air. 2 · Method according to item 1, characterized in that parts of the Al and / or Ge are replaced by Ag, so that alloys are melted, in which the alloying constituents are within a polygon in the ternary phase diagram Al-Ge-Ag, whose vertices from the points A (45 mass # Al, 55 mass # Ge, 0 mass # Ag) be formed.