CN-118663891-B - Preparation method of metal particles with core-shell structure

CN118663891BCN 118663891 BCN118663891 BCN 118663891BCN-118663891-B

Abstract

The invention discloses a preparation method of metal particles with a core-shell structure, which comprises the following steps of preheating inert gas flow loaded with high-melting-point metal powder, and then introducing the inert gas flow into flowing low-melting-point metal steam to enable the low-melting-point metal to be condensed on the surface of the high-melting-point metal powder to form a low-melting-point metal shell layer, wherein the temperature of the low-melting-point metal steam is T 1 , the preheating temperature is T 2 ,T 1 ＞T 2 , and the difference value between T 1 and T 2 is 50-200 ℃. According to the preparation method, the low-temperature high-melting-point metal powder airflow is introduced into the low-melting-point metal steam with higher flowing temperature, and the low-melting-point metal steam is in a flowing state due to the temperature difference, so that the low-melting-point metal can be quickly coagulated on the surface of the high-melting-point metal, a coating layer which is uniform in coating, free of segregation in components and good in interface combination is formed on the surface of the high-melting-point metal powder, and the mechanical property of the composite material made of the metal particles with the core-shell structure is improved.

Inventors

GAO PENGFEI
HAN SHENGLI
ZHANG YUGUI
ZHENG KAIHONG

Assignees

广东省科学院新材料研究所

Dates

Publication Date: 20260508
Application Date: 20240611

Claims (4)

1. The preparation method of the metal particles with the core-shell structure is characterized by comprising the following steps of: Preheating inert gas flow carrying high-melting-point metal powder, and then introducing the inert gas flow into flowing low-melting-point metal steam to enable the low-melting-point metal to be condensed on the surface of the high-melting-point metal powder to form a low-melting-point metal shell layer, so that the low-melting-point metal powder is prepared; The temperature of the low-melting-point metal steam is T 1 , the preheating temperature is T 2 ,T 1 ＞T 2 , and the difference between T 1 and T 2 is 50-200 ℃; the flow rate of the low-melting-point metal steam is 0.5-2 m/min; The flow rate of the inert gas flow loaded with the high-melting-point metal powder is 1-7 m/min; The inert gas flow loaded with the high-melting-point metal powder is introduced from the bottom of the low-melting-point metal steam; The difference between the melting points of the high-melting-point metal and the low-melting-point metal is not lower than 1000 ℃; the mass ratio of the low-melting-point metal to the high-melting-point metal powder is (2-5) 1; The low-melting-point metal is selected from one of Mg, zn and Al; The high-melting point metal is selected from one of Ti, nb and Mo.
2. The method for producing a metal particle of core-shell structure according to claim 1, characterized in that: The steam pressure of the low-melting-point metal steam is 1-3 MPa, and the steam concentration is 25-55%; And/or the thickness of the low-melting-point metal shell layer is 0.1-5 mu m.
3. The method for preparing metal particles with a core-shell structure according to claim 1, wherein the method is characterized in that inert gas flow loaded with high-melting-point metal powder is preheated, then the inert gas flow is introduced into low-melting-point metal steam with the flow rate of 0.5-2 m/min at the flow rate of 1-7 m/min, and the low-melting-point metal steam is pumped, the pumping rate is 0.5-2 m/min, so that the low-melting-point metal is condensed on the surface of the high-melting-point metal powder to form a low-melting-point metal shell layer.
4. A method for preparing metal particles with a core-shell structure according to any one of claims 1 to 3, wherein the preparation method is carried out under the protection of inert gas.

Description

Preparation method of metal particles with core-shell structure Technical Field The invention belongs to the field of materials, and particularly relates to a preparation method of metal particles with a core-shell structure. Background The surface modification of the metal particles is an important component of the engineering technology of the metal composite material, and has important significance for improving the original performance of the metal composite material. Refractory metals have high strength, high hardness and high temperature resistance, but have poor plasticity and are difficult to mold. Low melting point metals have low density and are easy to mold, but have poor strength. The integration of multi-metal characteristics can be realized by coating the metal on the surfaces of the metal particles, and the excellent composite material with multiple metal characteristics is prepared, so that the method has important significance for the development of metal-based composite materials. However, since melting temperature windows between metals with large melting point difference are not overlapped, the coating of the high melting point metal with the low melting point metal cannot be realized by conventional means. In addition, the coating between the mutually insoluble metals prepared in the prior art has the defects of poor interface bonding, component segregation and loose structure, and the defects limit the development of the metal composite material. Disclosure of Invention In order to overcome at least one technical problem of the prior art, one of the purposes of the present invention is to provide a method for preparing metal particles with a core-shell structure. The second purpose of the invention is to provide a metal particle with a core-shell structure. It is a further object of the present invention to provide a metal composite. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: The first aspect of the invention provides a method for preparing metal particles with a core-shell structure, comprising the following steps: Preheating inert gas flow carrying high-melting-point metal powder, and then introducing the inert gas flow into flowing low-melting-point metal steam to enable the low-melting-point metal to be condensed on the surface of the high-melting-point metal powder to form a low-melting-point metal shell layer, so that the low-melting-point metal powder is prepared; The temperature of the low-melting-point metal steam is T 1, the preheating temperature is T 2,T1＞T2, and the difference between T 1 and T 2 is 50-200 ℃. The temperature of the surface of the high-melting-point metal powder is lower than that of the low-melting-point metal vapor, and when the high-melting-point metal powder enters the low-melting-point metal vapor, the low-melting-point metal vapor can be condensed on the surface of the low-temperature high-melting-point metal to form a low-melting-point metal shell. Preferably, the flow rate of the low-melting-point metal steam is 0.5-2 m/min. Preferably, the flowing low-melting-point metal vapor is obtained by introducing heated inert gas into a reaction cavity filled with the low-melting-point metal vapor at a flow rate of 0.5-2 m/min, and the flowing inert gas drives the low-melting-point metal vapor to flow, so that the low-melting-point metal is flowing. Preferably, the flow rate of the inert gas flow loaded with the high-melting-point metal powder is 1-7 m/min. Preferably, the inert gas stream loaded with the refractory metal powder is introduced from the bottom of the low-melting metal vapor. The main purpose of the method of blowing high-melting point metal powder from the bottom upwards is to increase the floating travel of the high-melting point metal particles, provide enough time to help the low-melting point metal to condense on the surface of the high-melting point metal and improve the coating rate. Preferably, the low-melting point metal is selected from one of Mg, zn, and Al. Preferably, the high melting point metal is selected from one of Ti, nb, and Mo. Preferably, the difference in melting point between the high melting point metal and the low melting point metal is not lower than 1000 ℃. Preferably, the mass ratio of the low-melting metal to the high-melting metal powder is (2-5): 1. Preferably, the steam pressure of the low-melting-point metal steam is 1-3 MPa. Preferably, the vapor concentration of the low melting point metal vapor is 25 to 55%. The calculation formula of the steam concentration is V low melting point metal vapor /(V low melting point metal vapor +V Inert gas multiplied by 100 percent. Preferably, the thickness of the low-melting-point metal shell layer is 0.1-5 μm. Preferably, the low-melting point metal and the high-melting point metal are pretreated by acid liquor before use, and further preferably, the low-melting point metal and the high-melting point metal are pret