CN-117733144-B - Lanthanum oxide-added silver-nickel electrical contact material and preparation method thereof

Abstract

The invention discloses a lanthanum oxide-added silver-nickel electrical contact material and a preparation method thereof. The method comprises the steps of calculating the consumption of lanthanum oxide, nickel powder and Ag element required by preparing a contact, weighing the Ag element by silver nitrate and preparing a silver nitrate solution by using water, firstly reacting the lanthanum oxide with the silver nitrate solution, preparing a sodium hydroxide solution by using water according to the total consumption of sodium hydroxide required by completely reacting the lanthanum nitrate and the unreacted silver nitrate with sodium hydroxide respectively according to the amount of lanthanum nitrate and the amount of unreacted silver nitrate generated in the reaction, then reacting the sodium hydroxide solution with the suspension to obtain a composite powder of the silver oxide and the lanthanum hydroxide, washing the composite powder to be neutral, drying and roasting to obtain a silver lanthanum hydroxide composite powder, uniformly mixing the obtained silver lanthanum hydroxide composite powder with the nickel powder, and performing isostatic compaction, sintering and extrusion procedures to obtain the silver lanthanum hydroxide composite powder. The method can lead the lanthanum oxide to be more uniformly distributed in the silver matrix, and obtain a uniform metallographic structure.

Inventors

• HUANG XINGLONG
• XIONG JINGXIAN
• HUANG XIWEN
• XIE XIAOYU
• LUO WEI
• LI BO
• Mo Peisong

Assignees

• 桂林金格电工电子材料科技有限公司

Dates

Publication Date

20260512

Application Date

20231213

Claims (7)

1. 1. A preparation method of a silver-nickel electrical contact material added with lanthanum oxide comprises the following steps: 1) The method comprises the steps of calculating the required dosage of lanthanum oxide, nickel powder and Ag element according to the material proportion of a silver-nickel electrical contact to be prepared, weighing for standby, wherein the Ag element is weighed in a silver nitrate form, and then dissolved by water to prepare a silver nitrate solution; 2) According to the amount of lanthanum nitrate generated in the reaction and the amount of unreacted silver nitrate, the total amount of sodium hydroxide required by the complete reaction of the lanthanum nitrate and the unreacted silver nitrate and sodium hydroxide respectively to generate lanthanum hydroxide and silver oxide, weighing and then preparing a sodium hydroxide solution by using water for standby; 3) Adding sodium hydroxide solution into a suspension containing silver nitrate, lanthanum nitrate and silver oxide, and filtering after the reaction is completed to obtain composite powder of silver oxide and lanthanum hydroxide; 4) Washing the obtained composite powder of silver oxide and lanthanum hydroxide to be neutral, drying and roasting to obtain silver lanthanum hydroxide composite powder; 5) The silver-nickel electrical contact material added with lanthanum oxide is obtained by uniformly mixing the obtained silver-lanthanum hydroxide composite powder and nickel powder, and then performing isostatic pressing, sintering and extrusion processes, wherein the sintering adopts a step-type sintering process, specifically, the sintering is performed for 2-4 hours at 400-600 ℃, then for 1-2 hours at 600-800 ℃ and then for 3-6 hours at 800-920 ℃.
2. 2. The preparation method of claim 1, wherein in the step 1), the lanthanum oxide content is 0.5-5wt%, the silver content is 80-90wt% and the balance is nickel in the silver-nickel electrical contact material to be prepared.
3. 3. The method according to claim 1, wherein in the step 1), the concentration of the silver nitrate solution is 20-50wt%.
4. 4. The preparation method according to claim 1, wherein in the step 2), the total amount of sodium hydroxide is 5.9/25 to 8/25 of the weight of the silver nitrate weighed in the step 1).
5. 5. The method according to claim 1, wherein in step 2), the concentration of the sodium hydroxide solution is 20 to 30wt%.
6. 6. The method according to claim 1, wherein in step 4), the calcination is performed at 400 to 500 ℃.
7. 7. The silver-nickel-lanthanum oxide electrical contact material prepared by the method according to any one of claims 1-6.

Description

Lanthanum oxide-added silver-nickel electrical contact material and preparation method thereof Technical Field The invention relates to the technical field of silver-based electrical contact materials, in particular to a lanthanum oxide-added silver-nickel electrical contact material and a preparation method thereof. Background The silver-nickel (AgNi) material is a composite material which is formed by taking silver and nickel as main phases, and has the advantages of good electric conduction and thermal conductivity, low and stable contact resistance, good arc erosion resistance, high arc moving speed, excellent processing performance, simple production process, low manufacturing cost and the like, thus being the most preferable material in the application fields of photovoltaic relays and the like. However, the traditional silver-nickel material has some defects when being applied, such as high bearing current and high ambient temperature which are easy to generate fusion welding when being used for a relay in the photovoltaic field, so that the relay is invalid in control, and high splashing amount of the silver-nickel material when being used for a small relay in the intelligent household appliance field, so that the insulation pressure resistance of the relay with narrow space is destroyed after a period of operation, potential safety hazards are generated, and the fusion welding is easy to generate when the silver-nickel material is used for a button switch and the surge current is generated when the load of a lamp is switched on, so that the button switch is invalid in early stage. The addition of a proper amount of metal or metal oxide with high melting point and difficult decomposition into the silver-nickel material is a main means for improving the fusion welding resistance and the arc erosion resistance of the silver-nickel material. The rare earth oxide lanthanum oxide (La 2O3) has higher decomposition temperature (2315 ℃) than CdO and SnO 2, higher melting point and better stability. The La 2O3 has the advantages that the dispersion strengthening effect of La 2O3 in the high-temperature process can effectively prevent dislocation climbing and grain boundary sliding in silver nickel, so that the softening temperature and high-temperature strength of the contact material are obviously improved, and La 2O3 effectively prevents aggregation of Ni in the sintering process and aggregation of NiO and splashing of melted Ag under the action of electric arcs, so that the fusion welding resistance, wear resistance and stability of contact resistance of the silver nickel contact material are improved, in addition, la 2O3 has stable intrinsic properties and is not easy to reduce, and the La 2O3 does not react with H 2 in the sintering atmosphere of conventional AgNi production, so that La 2O3 becomes one of ideal additives of AgNi electrical contact materials. The preparation process of the AgNi electric contact material mainly comprises a mechanical powder mixing method, a mechanical alloying method, a chemical codeposition method and a chemical cladding method. The main step of the mechanical powder mixing method is powder mixing-sintering-extrusion, and the mechanical powder mixing method is widely adopted due to the simple processing technology, low manufacturing cost, easily controlled material components and high production efficiency. For example, patent documents of the invention such as CN106298293A, CN114058884A, CN 101608272A, etc. all provide a method for preparing AgNi containing additives by adding the additives in a powder mixing manner and adopting a mechanical powder mixing method as a large process route, but due to the characteristics of small content of the additives, poor dispersibility, poor wettability, etc., the problem of segregation of the additives and poor combination of the additive phase and a silver interface of a matrix is easy to exist when the additives are added in a simple powder mixing manner. The invention patent document with publication number of CN103555980A, CN103667767A and the like prepares AgNi material by firstly smelting and atomizing metallic elements such as La, ce, bi, cu, in, zn and the like and silver to prepare silver powder containing additives, and then mixing, sintering and extruding the silver powder and Ni powder. The problem of additive segregation can be ameliorated by adding the additive by means of melting atomization, but this method is limited to adding metallic elements. The invention patent document with publication number CN103710564A provides a preparation method of an additive-containing silver-nickel electrical contact material, specifically, silver powder or nickel powder is added into an aqueous solution or an ethanol solution prepared by dissolving salt compounds containing additive elements with water or absolute ethanol, and then wet mixing, drying and sintering are carried out to uniformly distribute metal simple substances and/or