CN1119842C

CN1119842C - Electrically conductive terminal cast with Al-Cu alloy

Info

Publication number: CN1119842C
Application number: CN00100352A
Authority: CN
Inventors: 向世芬
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-01-18
Filing date: 2000-01-18
Publication date: 2003-08-27
Anticipated expiration: 2020-01-18
Also published as: CN1270428A

Abstract

The present invention relates to a method of casting an electrically conductive joint with aluminium and copper, and a product thereof. After the surface of a copper base body is processed, the copper base body is in casting connection with molten liquid of molten aluminium alloy. Connecting surfaces of the copper base body and an aluminium base body of an electrically conductive heat head of the present invention are completely coated in the aluminium base body without the influence of environment atmosphere oxidation corrosion. The product has the advantages of favorable reliable performance and stable performance.

Description

Electrically conductive terminal cast with Al-Cu alloy and manufacturing process thereof

Technical field

The present invention relates to a kind of casting interconnection technique of dissimilar metal, especially a kind of aluminium--the technology of conductive contact is made in casting in bronze.

Background technology

Aluminium, copper is owing to have excellent electric conductivity, and adopted in a large number in electric, field of metallurgy.General lead, bus all are to make of this metal, in a lot of occasions of modern production, usually need these two kinds of metals are coupled together to satisfy the needs of big electric current, low-voltage, the design of high-effect power consumption equipment.

In the prior art, link together as conductive contact with aluminium, copper, its connected mode mainly contains the conductive contact with the bolt mechanical connection, with the conductive contact that is connected with rolling pressure welding.The bolt mechanical connection is the simplest, uses comparatively generally, and it is the Mechanical Contact that relies on two kinds of intermetallic contact-making surfaces, the realization current delivery, its shortcoming is that oxidation and electrochemical corrosion easily take place the contact-making surface of two metals in use, and resistance increases, thus the reliability of making, bad stability.Connect system's manual operations with bolt simultaneously, be difficult to realize mechanization.Conductive contact is made in rolling and pressure welding, and conductivity and reliability all are better than mechanical connection, but this connection needs special equipment, and is only limited to the plane connection of two kinds of metal homalographics.

Make conductive contact, Japan's special permission for casting method aluminium, copper being connected: the clear 37-28060 of closing discloses a kind of " making the deposited method of aluminium alloy and dissimilar metal " and has mentioned in dissimilar metal founding again after particularly aluminize earlier in the surface of cast iron.Chinese patent 94231626-6 and 96245759-0 disclose the utility model of " large-scale copper-aluminium transition joint " and " copper aluminum casting transitional facility terminal " respectively, but its method of how to cast is not seen description.

Summary of the invention

The objective of the invention is to manufacturing process of the electrically conductive terminal cast with Al-Cu alloy that discloses a kind of bonding strength height, conduct electricity very well and products thereof.

As everyone knows, dissimilar metal is made conductive contact, and wherein two key problems are bonding strength and the electric conductivities between the dissimilar metal.The assurance of electrically conductive terminal cast mechanical strength except carrying out the rational shaped design, need guarantee in manufacture process that also the densification of aluminium portion matrix and copper portion matrix and the combination between the aluminum bronze matrix are firm.Obtaining of excellent conducting performance also is so, and the various impurity elements in the aluminum bronze all can make its electric conductivity that in various degree decline is arranged, and this is just to the selection of aluminium material and copper material and the melting process strict demand of aluminium material.

Here the resistance value with conductive contact is decomposed into three parts, i.e. aluminium portion matrix resistance R ₁, copper portion matrix resistance R ₂, aluminum bronze joint portion resistance R ₃, its resistance total value R=R ₁+ R ₂+ R ₃We know, for R ₁And R ₂Can easier raw material impurity be controlled by the selection and the melting process of raw material, be made R ₁And R ₂Drop to minimum.Therefore the reduction of conductive contact all-in resistance and the acquisition of mechanical strength depend primarily on aluminum bronze connecting portion resistance R in the casting process ₃Attenuating and the raising of aluminum bronze faying face intensity, this also is the problem that the present invention endeavoured to solve.

According to the data introduction, when high temperature aluminum liquid contacts at short notice with solid copper, copper spreads in aluminium, aluminium also spreads in copper, but because the speed that diffusion ratio spreads in solid in liquid is fast, so can think it mainly is that copper spreads in aluminium, just can generate intermetallic compound Al stable under the room temperature like this between the aluminum bronze ₂Cu, Al ₂Cu is a brittle substance, 548 ℃ of fusing points, and resistivity is about more than six times of fine aluminium, б _bBe about 5Mpa, can not satisfy the technical requirement of conductive contact fully.

The present invention when the casting Al-Cu conductive contact, with the copper spare of solid state through preheating (in the test copper spare is heated to 300 ℃--400 ℃ insulation 1--2 hour) after, row casting again.The surface of copper easily produces oxide-film when it should be noted that preheating.This oxide-film Cu ₂O fusing point height (1222 ℃--1235 ℃), the temperature of aluminium liquid is generally at 740 ℃ in the casting cycle--and 780 ℃, oxide-film can not be melted fully and penetrate.So this oxide-film can influence bond strength and electric conductivity between the copper aluminium.

In order to obtain the bond strength height, the conductive contact that resistivity is low, the present invention has also adopted following special measure.After copper spare machining, at first good at copper spare electroplating surface one deck and aluminum bronze intersolubility, simultaneously it has the metal of excellent conductive performance with the dissolve each other alloy of back formation of aluminum bronze, as: precious metals such as silver, cadmium, nickel, titanium, as transition zone, and then under the atmosphere of reproducibility with the preheating of copper spare, the copper spare after the preheating is positioned in the mold, last cast aluminum alloys solution is finished the casting of aluminum bronze conductive contact.Take this method can make the copper surface be difficult for oxidation, simultaneously when casting, the coat of metal on copper surface is easy at copper spare surface wettability aluminium liquid, the coated metal good with the aluminum bronze intersolubility, in aluminium liquid, spread simultaneously, finally form the linkage interface of smooth aluminium-coating-coating-copper at the connecting portion of aluminum bronze matrix.This linkage interface had both satisfied high-intensity mechanical performance, had satisfied excellent conducting performance simultaneously again.

Conductive contact with above-mentioned casting method making, the faying face of copper and two kinds of metals of aluminium is intermediate metals (copper-coating-coating-aluminium) of a kind of alloy state, this faying face is under the coating fully of aluminum metal simultaneously, can directly not be subjected to the influence of ambiance oxide etch, the unfailing performance and the stability of joint are guaranteed.In addition, make owing to this joint pours into casting mold coating copper spare by liquid aluminium, thereby the shape of aluminum bronze contact-making surface is restricted hardly, can be Any shape, thereby is that the optimized design that realizes conductive contact has been created condition.This conductive contact can satisfy strict technical requirement fully.

Description of drawings is described further electrically conductive terminal cast with Al-Cu alloy of the present invention and method thereof below in conjunction with the embodiment accompanying drawing.

Fig. 1 is the profile of a kind of aluminum bronze conductive contact of the present invention

Fig. 2 is the copper spare before the casting

Fig. 3 is the Electronic Speculum structure of aluminum bronze joint portion

The raw-material selection of embodiment: it is 99.7% No. two copper plates that copper material is selected purity for use.It is 99.7% highly purified industrial aluminium ingot that aluminium is selected purity for use.

Aluminium is melted in the graphite crucible stove, be incubated stand-by at 740 ℃-780 ℃.

Copper spare is processed into shape as shown in Figure 2 as required, in order to improve the mechanical strength of joint, on the copper spare dispersion processing three circular holes 3, also can be processed into some grooves.Copper spare after the machining is carried out Nickel Plating Treatment.Copper spare after the plating cleans through soda boiling, it is preheated to heat preservation for standby use in 250 ℃ of-380 ℃ of degree scopes again under the atmosphere of reproducibility.

Metal mold is adopted in casting, and 200 ℃-400 ℃ of casting mold preheat temperatures reserve the position of placing copper coin in the casting mold.

Be matched moulds at last, the copper spare of preheating is put into the precalculated position of casting mold, again high temperature aluminum liquid is poured into a mould in mold, get final product depanning after solidifying, take out after in 300 ℃-400 ℃ holding furnace, being incubated 3-4 hour again and carry out Surface Machining, excise casting gate, finish the casting process of whole aluminum bronze conductive contact.

Conductive contact shown in Figure 1, a kind of aluminum bronze conductive contact schematic diagram of casting of method provided by the invention exactly, most of matrix of copper spare 1 all is coated in the cast aluminium matrix 2, and the upper end of copper spare 1 is exposed and is used as conducting terminal.The surface of copper spare matrix is coated with intermediate metal.

Fig. 3 is the Electronic Speculum structure chart of this conductive contact aluminum bronze binding site.The centre that therefrom can see copper spare 1 and cast aluminium 2 clearly is a metallic nickel transition zone 4, and the both sides of this intermediate metal 4 have copper and coating nickel the dissolve each other alloy-layer 5 of diffusion and the alloy-layer 6 that aluminium and coating nickel dissolve each other and spreads respectively.The alloy-layer 5,6 on intermediate metal 4 and its both sides has been formed the linkage interface of aluminum bronze jointly, and this linkage interface not only has enough mechanical strengths, has excellent conducting performance simultaneously.

When the conductive contact of this method casting is used for Zinc electrolysis negative plate, can realize the overlap joint between minus plate and the bus-bar, promptly rely on the deadweight of minus plate, copper spare exposed junction directly contacts with bus-bar, and reaches the transmission of electric current.This method of attachment is to realize minus plate installation mechanization and adopt the requisite prerequisite of zinc mechanization.

Claims

1, the manufacturing process of electrically conductive terminal cast with Al-Cu alloy, be to cast in metal mold with the aluminium liquid of molten state after the preheating of copper spare, the intersolubility that the surface electrical that it is characterized in that copper spare is coated with one deck and aluminium, copper is good, and with aluminium, the copper metal that alloy that the back forms has good electrical properties that dissolves each other, the preheating of copper spare is to carry out under a kind of reducing atmosphere.

2, the method for electrically conductive terminal cast with Al-Cu alloy as claimed in claim 1 is characterized in that the electroplating surface nickel dam of copper spare.

3, the conductive contact cast of the method for electrically conductive terminal cast with Al-Cu alloy as claimed in claim 1 is characterized in that having between copper spare and the cast aluminium intersolubility of one deck and aluminium, copper good, and with aluminium, the copper metal level that the alloy that produces has good electrical properties that dissolves each other.

4, conductive contact as claimed in claim 3 is characterized in that the joint face of copper and aluminium is coated by aluminium, the linkage interface of being made up of aluminium-coating-coating-copper between copper and the aluminium.

5, as claim 3,4 described conductive contacts, it is characterized in that the linkage interface of forming by aluminium-nickel-nickel-copper between the aluminum bronze

6, conductive contact as claimed in claim 5 is characterized in that being processed with hole or the groove that is used to strengthen the aluminum bronze bonding strength by the copper spare that the aluminium casting coats.