FIELD OF THE DISCLOSURE

The field of the disclosure pertains to the production of fine metallic powders for application in the electronic industry, metal injection forming, thermal spraying, thermal spray welding, 3D printing.

BACKGROUND OF THE DISCLOSURE

During the last decades, electronic devices and components have been significantly reduced in size. This has a direct impact on the dimensions of internal components and metallization of such devices. Solder paste is widely used for point contacts between the different components or layers inside electronic devices. These paste are composed of metallic powders and of fluxes, to ensure proper melting and adhesion to other components. The metallic components in the soldering paste is generally in the form of a “low melting point alloy” or “low melting point metal” and the size distribution of such metallic powder depends on size of the point contact. Smaller electronic devices and components requiring smaller contacts, hence a growing demand is seen for solder paste with metallic powders having smaller size distribution. It is not uncommon to have required or requested particle size distribution mostly under 20 and even under 10 microns.

There are multiple other applications for fine metallic powders, such as metal injection forming, thermal spraying, thermal spray welding, 3D printing and many more.

Conventional techniques (atomization, centrifugal disintegration, water atomization . . . ) can produce fine powders, but the particle size standard deviation and the spherical shape of the particles are difficult to achieve from low melting point alloys. This often leads to a low recovery of the produced powder in a defined size fraction from these technologies.

SUMMARY OF THE DISCLOSURE

The present disclosure describes a new production process for metallic powders having low melting points. This process produces fine spherical powders with a small standard deviation on the particle diameter.

In a first aspect, there is provided a low melting point metal or alloy powder atomization manufacturing process. In at least one embodiment, the process may include: providing a melt of said low melting point metal or alloy through a feed tube; diverting said melt at a diverting angle with respect to a central axis of the feed tube to obtain a diverted melt; directing the diverted melt to an atomization area; and providing at least one atomization gas stream to the atomization area.

The atomization process may be being carried out in the presence of water within an atomization chamber used for said atomization process.

In a second aspect, there is provided a low melting point metal or alloy powder atomization manufacturing process. The process may include

providing a melt of said low melting point metal or alloy through a feed tube; delivering said melt through a diverter to an atomization area; providing at least one atomization gas stream to the atomization area; and

delivering water to an atomization chamber used for said atomization process. In such process, prior to being delivered to the atomization area, the melt may be diverted in the diverter at a diverting angle with respect to a central axis of the feed tube.

In a third aspect, there is provided a low melting point metal or alloy powder atomization manufacturing process. The process may include

providing a melt of said low melting point metal or alloy through a feed tube; directing the melt to an atomization area; and

providing at least one atomization gas stream having an average gas velocity of at least 300 m/s, to the atomization area, wherein a ratio of the atomization gas to the low melting point metal in the atomization area is about 5 000 to about 30 000 cm3of gas per cm3of metal to atomize, thereby providing a distribution of powder with an average particle diameter under 20 microns with geometric standard deviation of lower than about 2.0.

In a fourth aspect, there is provided a low melting point metal or alloy powder atomization manufacturing process. The process may includeproviding a melt of said low melting point metal or alloy through a feed tube; optionally diverting said melt at a diverting angle with respect to a central axis of the feed tube to obtain an optionally diverted melt;

directing the optionally diverted melt to an atomization area; and providing at least one atomization gas stream having a velocity of at least 300 m/s, to the atomization area, wherein a ratio of the atomization gas to the low melting point metal in the atomization area is about 5 000 to about 30 000-cm3 of gas per cm3 of metal to atomize, thereby providing a distribution of powder particle sizes having geometric standard deviation of lower than about 2.0.

