JPH0426704A - Manufacture of fine gold ball - Google Patents

Abstract

PURPOSE:To obtain fine gold ball having the fixed particle size and shape with good yield by crushing and pulling off gold fine wire to make fine gold block, heating this on the way of dropping to make molten ball and then, rapidly cooling. CONSTITUTION:The gold fine wire having the fixed diameter is crushed and pulled off to make the fine gold block. This fine gold block 9 is uncontinuously dropped from a feeder 11. Below outlet 11B in the feeder, a heating cylinder 12 is set and the fine gold block 9 dropped by gravity becomes molten state with heating. Then, this is made to the molten ball 13 with the gravitation and surface tension. The molten ball 13 is further dropped with the dead wt. and rapidly cooled in water 15, etc., in a vessel 14 to make the fine gold ball 16 having about 55mum diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing fine gold spheres having uniform size and shape.

[Conventional technology]

Generally, a gas atomization method or a water atomization method is known as a method for producing metal powder. This is a method of producing metal powder by applying a gas or water jet to a drip stream of molten metal to atomize and rapidly cool the molten metal. FIG. 3 illustrates a method for manufacturing fine gold spheres by this gas atomization method.

Gold is melted in a melting furnace 51, and molten gold 52 at a constant temperature is pooled. This molten gold 52 is dripped from a drip nozzle 53 to form a thread-like drip stream 54.

This drip stream 54 is located within the jet stream of the atomizing nozzle 56 from which the inert gas 55 is jetted. Due to the gas turbulence 57,
The gold drip stream 54 is atomized and becomes fine gold spheres 58 . The fine gold spheres 58 fall into the water 60 of the tank 59 and are rapidly cooled, settling at the bottom of the tank 59. Thereafter, through a sorting process, fine gold spheres of a predetermined particle size are obtained. In addition, in order to make the shape of the fine gold sphere 58 as ball-like as possible,
A high temperature gas may be used as the inert gas 55.

Furthermore, in order to produce finer gold particles, there is also one in which the two atomizing nozzles 56 are arranged in a downward-facing square square shape, with the dripping stream 54 located in the center of the square square shape.

[Problem to be solved by the invention]

In the method for producing fine gold spheres using the gas atomization method described in the conventional technology, molten gold is atomized by gas turbulence, so the particle size distribution is wide and the shape is often irregular rather than a ball. Therefore, a sorting step is required to select those having a predetermined particle size and ball shape from among these fine gold spheres. However, there were problems in that it was extremely difficult to sort out the fine gold spheres, including their shape, and the yield was low.

The present invention has been made in view of the above-mentioned problems of the conventional technology, and its purpose is to provide a method for manufacturing fine gold spheres with a constant particle size and shape with a high yield. It is something.

[Means to solve the problem]

In order to achieve the above object, the method for producing fine gold balls according to the present invention involves crushing and tearing a certain length of thin gold wire into fine gold ingots, dropping the fine gold ingots discontinuously, A fine gold ingot is heated to form a molten ball, and this molten ball is rapidly cooled to form a fine gold ball.

[Function] The fine gold nuggets formed by crushing and tearing a certain length of thin gold wire have a constant weight, and when they are melted into fine gold balls, there is no variation in particle size, and furthermore, there is no variation in particle size during discontinuous falling. Due to heating, gravity and surface tension create a uniform ball shape.

〔Example〕

Examples will be described below with reference to the drawings.

Figure 1 is a diagram showing the process of manufacturing fine gold ingots from fine gold wire;
FIG. 2 is a diagram showing the process of turning fine gold ingots into fine gold spheres.

First, the process of manufacturing fine gold ingots from fine gold wire will be explained.

As shown in FIG. 1(d), a fine gold ingot is manufactured from the gold JR wire by the joint work of the bonder 2 and the substrate 3. The bonder 2 consists of a clamp 8, a capillary 4, and a spark electrode 5. Clamp 8 is gold wire 1
The opening/closing timing is controlled so that the thin gold wire 1 can be controlled to a constant length. The capillary 4 has a central hole 4A through which the thin gold wire 1 is passed.
It has a conical hole 4B at the tip of the center hole 4A, and the whole can be moved up and down. The spark electrode 5 is slidable between a position facing the conical hole 4B and a retracted position. The substrate 3 is, for example, a silver plating layer 3.
It consists of A and a base 3B. The method for manufacturing fine gold ingots using the bonder 2 and substrate 3 having the above structure is as follows. FIG. 1(a) shows the start time. When the thin gold wire 1 is made to protrude from the conical hole 4B and the capillary 4 is pressed against an appropriate base 7, the thin gold wire 1 is exposed to the LA.
crushed by lines. Next, as shown in Figure 1(b),
When the capillary 4 is raised and the clamp 8 is closed at a certain length of the gold wire 1, the gold wire I is torn off. Then, as shown in FIG. 1(C), a certain length of the wire-like thin wire IB protrudes from the conical hole 4B. Next, as shown in FIG. 1(d), when the spark electrode 5 is slid to a position facing the conical hole 4B and a discharge is caused between the spark electrode 5 and the wire-like thin wire IB shown in FIG. 1(c), the fine gold wire 1 A ball IC is formed at the tip of. Next, as shown in FIG. 1(e), the capillary 4 is pressed against the substraight 3 with a predetermined constant pressure. At this time, the clamp 8 is open. Figure 1 (d
) is crushed into a nail-shaped fine gold nugget 9, which adheres closely to the silver plating layer 3A. Next, as shown in FIG. 1(f), when the capillary 4 is raised and the clamp 8 is closed, the thin gold wire 1 is torn off, and as shown in FIG.
As shown in g), the fine gold ingots 9 remain on the silver plating layer 3A of the substrate. And Zabstra 1.
3 or the bonder 2 moves in either the X direction or the Y direction and returns to the state shown in FIG. 1(c). This figure 1 (c) - (
By repeating g) at high speed (for example, 5 times/second), a large number of fine gold ingots 9 are formed in close contact with the silver plating layer 3A of the substrate. When the silver plating layer 3A of this substrate is dissolved with an electrolytic solution or acid, the fine gold nuggets 9 are separated and recovered. Note that a copper plating layer or an unplated copper plate may be used instead of the silver plating layer 3A of the substray l-.

By the way, it is desirable to use the thin gold wire 1 manufactured as follows. Total purity is 99°99% by weight
Using the above electrolytic gold, a trace amount of yttrium, calcium, copper, helium, etc. is added in a total amount of about 50 to 100 ppm by weight to produce a gold alloy with improved room temperature strength and heat resistance. This gold alloy is melted and cast in a high frequency vacuum melting furnace,
After rolling the ingot, it is drawn into a fine gold wire at room temperature.

Although the final wire diameter of such a fine gold wire is not particularly limited, it is preferably 10 to 50 μmφ in practice. The thin gold wire used is one that has been continuously annealed in an air atmosphere and tempered to have an elongation value of 2 to 10%. The diameter of the fine gold spheres obtained in the present application is not particularly limited, but it is preferable to obtain fine gold spheres with a diameter of approximately 20 to 150 μm based on the practical wire diameter size of the fine gold wire described above. To illustrate one embodiment of the present application, first, by using a thin gold wire 1 of 20 μmφ, discharge conditions are controlled so that the diameter of the ball IC is 2.5 times the diameter of the thin gold wire 1, and this ball IC is pushed. Nail head-shaped fine gold ingots of approximately 70 μm in size are obtained by crushing and tearing. By the way, the above-described gold alloy having heat resistance is suitable for cutting the fine gold wire 1 having a high recrystallization temperature near the nail head-shaped fine gold ingot 9 when forming the fine gold ingot 9 in the present application. As a result, fine gold ingots 9 having a constant weight can be obtained.

Next, a process of turning the above-mentioned fine gold ingots into fine gold spheres will be explained. In FIG. 2, fine gold ingots 9 are dropped discontinuously by a feeder 11. Here, discontinuously refers to a state in which the fine gold ingots 9 are supplied separately with distances in the vertical and horizontal directions, as shown in the figure. As such a feeder 11, there is a vibration feeder having a fixed ultrasonic transmitter 11A. A heating cylinder 12 is disposed below the feeder outlet JIB, and the fine gold ingots 9 falling by gravity are heated to become molten. Then, it becomes a molten ball 13 due to gravity and surface tension.

In addition, since it is originally a fine gold nugget 9, it becomes a molten ball 13 as soon as it is melted and JJ. This heating cylinder 12 has a burner 12A on its side, and heats the fine gold ingots 9 while preventing them from coming into contact with each other using a heating swirling flow (2) directed downward. Note that instead of the heating cylinder 12 using the burner 12A, a dielectric heating device filled with inert gas may be used.

Then, the molten ball 13 further falls under its own weight and is rapidly cooled in the water 15 of the container 14, becoming a fine gold ball 16 with a diameter of 55 μm. Note that the cooling means is not limited to rapid cooling using water 15, but may be based on gas air cooling.

According to the above process, a certain length of a thin gold wire of a certain thickness is crushed and torn to pieces to obtain a fine gold ingot 9 of a certain weight, and the fine gold nugget 9 that is freely falling in pieces is melted and finely divided. Since the gold spheres 16 are used, they are easily formed into molten balls, and the particle size and shape are uniform, which greatly improves the yield.

〔Effect of the invention〕

As explained above, the method for producing fine gold balls according to the present invention involves crushing and tearing a certain length of thin gold wire to obtain fine gold nuggets, dropping the fine gold nuggets discontinuously, and discontinuously dropping the fine gold nuggets while they are falling. is heated to form a molten ball, and this molten ball is rapidly cooled to form fine gold spheres.Since a certain weight is melted to form fine gold spheres, there is no variation in particle size.
Furthermore, since the heating is performed discontinuously during falling, the ball becomes uniform in shape due to gravity and surface tension. Therefore, fine gold balls having a uniform ball shape can be produced with constant accuracy and high yield. Furthermore, an extremely complicated sorting process is no longer necessary.

[Brief explanation of drawings]

Figure 1 is a diagram showing the process of manufacturing fine gold ingots from fine gold wire;
Figure 2 is a diagram showing the process of turning fine gold ingots into fine gold balls, Figure 3
The figure shows a method of manufacturing fine gold spheres by the conventional gas atomization method, and the explanations of the main symbols in the figure are as follows. 1... Gold thin wire, 2... Bonder (crushing, pulling and shredding means), 9...
- Fine gold ingot, 12... Heating cylinder (heating means), 13... Molten ball, 15... Water (cooling means), 16... Fine gold ball.

Claims (1)

[Claims] (1) A certain length of thin gold wire is crushed and torn into fine gold ingots, the fine gold ingots are dropped discontinuously, the fine gold ingots are heated in the middle of falling to form molten balls, and the molten balls are rapidly cooled. A method for producing fine gold spheres, characterized in that the fine gold spheres are produced by