KR-102963637-B1 - Method for producing alloy powder and alloy powder, paste, and capacitor produced by said method

Abstract

The present invention discloses a method for producing alloy powder and alloy powder, paste, and capacitors produced by the method. The method can obtain particles with a shape closer to spherical, and the solidified particles form a relatively dense surface layer after quenching. The surface layer, where a chemical passivation reaction has occurred, is compressed by physical impact to form a dense protective layer. The highly stable alloy powder particles have more stable chemical properties and good dispersibility.

Inventors

• 자오, 덩용
• 펑, 지아빈
• 리, 룽청
• 천, 강치앙
• 시, 웨이

Assignees

• 지앙수 보첸 뉴 머티리얼즈 스톡 씨오., 엘티디.

Dates

Publication Date

20260511

Application Date

20220225

Priority Date

20211111

Claims (9)

1. A method for producing alloy powder comprising the following steps: (1) A step of transporting a molten metal droplet by means of a carrier gas at a temperature higher than the melting point of the metal, sending the metal droplet to a thermal radiation region, and cooling until solidified to obtain particles, wherein the metal content in the metal droplet exceeds 99.9 wt% and the metal raw material in the metal droplet is nickel; (2) A step of mixing solidified high-temperature solid particles with a fluid at room temperature and quenching, wherein the average temperature of the particles and carrier gas before quenching is higher than 500℃ and the average temperature of the particles and carrier gas after quenching is lower than 300℃. (3) A step of bringing the surface of a metal droplet or particle into contact with an oxygen group element during the metal droplet formation process, after solidification, or after quenching, so that a chemical passivation layer is formed on the particle surface by reaction with the oxygen group element to produce a nickel compound containing the oxygen group element, wherein the amount of the oxygen group element is controlled so that the mass of the oxygen group element is 0.10 to 15.00 wt% of the mass of the alloy powder. (4) A step of dispersing an alloy powder having a chemical passivation layer containing an oxygen group element into a fluid in a container having a housing with a hard inner wall at room temperature, and the fluid carrying the alloy powder by pressure and rotating it within the container, such that the rotating particles collide with each other or the rotating particles collide with the hard inner wall of the housing of the container, thereby making the chemical passivation layer on the surface of the particles more dense.
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3. A method for producing alloy powder according to claim 1, wherein the carrier gas is at least one of nitrogen or argon.
4. A method for producing alloy powder according to claim 1, wherein the fluid in step 2 is at least one of an inert gas or a liquid.
5. A method for producing an alloy powder according to claim 1, wherein the oxygen group element is at least one of oxygen or sulfur.
6. A method for producing an alloy powder according to claim 1, wherein the average particle size of the alloy powder is 20 to 1000 nm, the single particle is spherical in shape, the metal content in the particle is 84.00 to 99.80 wt%, the content of non-metal and non-oxygen group elements is 0.01 to 1.00 wt%, the content of oxygen group elements is 0.10 to 15.00 wt%, and the oxygen group elements exceeding 90 wt% content are concentrated within the outer surface layer of the particle with a thickness of 5 nm.
7. Alloy powder produced by a method for producing alloy powder according to any one of paragraphs 1 and 3 to 6.
8. A conductive paste comprising alloy powder according to claim 7.
9. A multilayer ceramic capacitor comprising an electrode made of a conductive paste according to claim 8.

Description

Method for producing alloy powder and alloy powder, paste, and capacitor produced by said method The present invention relates to a method for producing metal alloy powder suitable for electronic applications, more specifically, a method for producing a highly stable alloy powder used as a conductive powder in a conductive paste, and also to an alloy powder produced by the method, a conductive paste produced by the alloy powder, and a multilayer ceramic capacitor produced by the conductive paste. The alloy powder, which is the main component of the conductive paste used in the electrode manufacturing process of multilayer ceramic capacitors, is required to contain as little unnecessary impurities as possible so as not to affect conductivity. However, as the number of stacked layers in multilayer ceramic capacitors increases, the conductive powder is required not only to have good conductivity but also to have good adhesion during the simultaneous firing process with the ceramic insulating layer and glass powder. Furthermore, the conductive powder is required to have similar thermal expansion to prevent swelling and cracking between layers or to prevent bending and breakage of the ceramic body due to differences in thermal expansion between layers. Therefore, conductive powders are required to have a relatively high sintering initiation temperature and possess good co-firing characteristics with oxide ceramic powders or glass powders. Furthermore, given the relatively long time required to fabricate multilayer ceramic capacitors from powders under the international division of labor (sometimes exceeding 30 days), metal powders are also required to possess relatively high stability. To maintain powder stability, the powders can be packaged in a vacuum or inert atmosphere, or the powder surfaces can be coated. While powders can be treated using oxygen enrichment or sulfur enrichment processes to improve the co-firing characteristics of metal and ceramic powders, micromaterials, particularly nanomaterials, have very large specific surface areas and high chemical activity. Consequently, chemical reactions are prone to occur within the powder particles during these processes, and uneven and unstable chemical passivation or coating layers on the powder surfaces are also likely to develop. Additionally, if the chemical passivation layer on the powder particle surface is not effectively controlled, reactions can continue to occur within the particles, affecting the stability of the metal powder. Regarding the problems of the background technology, the present invention provides a method for producing high-stability alloy powder by producing high-stability alloy powder through a combination of a thermal radiation solidification process, a quenching cooling process, a surface chemical passivation process, and a surface physical passivation process. To achieve the above objective, the present invention is realized by the following technical method. Specifically, a method for producing high-stability alloy powder comprising the following steps: 1. A step of transporting a molten metal droplet by means of a carrier gas at a temperature higher than the melting point of the metal, sending the metal droplet to a thermal radiation region, and cooling until solidified to obtain particles, wherein the metal content in the metal droplet exceeds 99.9 wt%; 2. A step of mixing solidified high-temperature solid particles with a fluid at room temperature and rapidly quenching, wherein the average temperature of the particles and carrier gas before quenching is higher than 500℃ and the average temperature of the particles and carrier gas after quenching is lower than 300℃, thereby obtaining a dense and stable alloy powder particle structure. 3. A step of contacting the surface of a metal droplet or particle with an oxygen group element during the metal droplet formation process, after solidification, or after quenching, so that a chemical passivation layer is formed on the particle surface by reaction with the oxygen group element to produce a nickel compound containing the oxygen group element, wherein the amount of the oxygen group element is controlled so that the mass of the oxygen group element is 0.10 to 15.00 wt% of the mass of the alloy powder. 4. A step of dispersing an alloy powder having a chemical passivation layer containing an oxygen group element in a fluid of a container having a housing with a hard inner wall at room temperature, wherein the fluid carries the alloy powder by pressure and causes it to rotate within the container, such that the rotating particles collide with each other or the rotating particles collide with the hard inner wall of the housing of the container, thereby causing the chemical passivation layer on the surface of the particles to become denser. In addition, the metal raw material in the above metal droplet is at least one of nickel or copper. In addition, the carrier gas is at least one of n