Silver/nickel/rare earth oxide/carbon contact and production method thereof
One, affiliated technical field
The present invention relates to a kind of silver-based contact and production method thereof that is used for low-voltage electrical apparatus such as contactor, circuit breaker etc.
Two, background technology
In the low-voltage electrical apparatus field, contact silver-based material commonly used is made, as silver/nickel contact material, silver/oxide contact tip material, silver/carbon contact material etc.Silver/nickel contact material is a kind of contact material that uses under little electric current, this drawing abillity and welding performance are good, but the ability of its resistance fusion welding and arc resistant scaling loss a little less than, can not enlarge its scope of application, and this material all is to use powder metallurgy method production, thereby the skewness of nickel influences its serviceability.Silver/oxide (as cadmium oxide, zinc oxide etc.) contact material, oxide distribute at silver-colored intragranular, and granular size is relatively more consistent, the distribution disperse.The arc resistant scaling loss ability of material is good, is mainly used in the contactor of medium current, and range of application is more extensive.But its processing and welding performance are poor, and in addition, the oxide content of this material has certain restriction, can not be used for electrical equipment such as the contactor of big electric current and circuit breaker.Silver/carbon (being mainly graphite) contact material is by powder metallurgy method production, its breaking capacity and connection performance are fine, be mainly used in electrical equipment such as various circuit breakers, but its arc resistant scaling loss ability, useful life is short, and makes the arc-control device carbon distribution easily, causes phase fault, this drawing abillity and welding performance are poor especially, thereby limit its scope of application.Above-mentioned three class silver based contact materials be use in recent years contact material the most widely, but its shortcoming is arranged all, the content of the silver in silver/oxide and silver/carbon contact material is all very high in addition, production cost is higher.
Now, internal oxidation and powder metallurgic method are generally adopted in the production of silver based contact material, these two kinds of methods all have certain limitation, the contact material oxide of producing as internal oxidation distributes in silver-colored crystal grain, the oxide granularity is consistent, but its oxide content can not be too high, and oxide is inconsistent on the surface of contact and inner content, anti-sulfuration and resistance fusion welding a little less than.And the contact material of producing with powder metallurgy process, the metal of the not solid solution that is added or oxide are not to be distributed in the silver-colored crystal grain, but on the crystal boundary or phase boundary that distribute, skewness, and granule size is also uneven.
Three, summary of the invention
The object of the present invention is to provide a kind of silver/nickel/rare earth oxide/carbon contact, the galvanoplastic production of its material has overcome the shortcoming that above-mentioned three kinds of contact materials exist and has had their advantage.
For achieving the above object, the solution that the present invention takes is: a kind of silver/nickel/rare earth oxide/carbon contact, the composition proportion of its material are (percentage by weight): carbon 0.1~2.0, yttria 0.1~15, nickel 5.0~50, silver-colored surplus.
The production method of a kind of above-mentioned silver/nickel/rare earth oxide/carbon contact adds yttria and carbon in the silver-nickel electroplate liquid, use silver plate and nickel plate as anode, and corrosion resistant plate is as negative electrode, and cathode-current density is 1.5~3.0A/dm
2Electroplating current adopts the DC power supply or the pulse power, negative electrode is used the plastics mold and is shielded, solution need stir during plating, plating bath is through outside the general plating solution maintenance, and the content of the suspended matter of plating bath is monitored, and regularly replenishes, electroplating velocity is 50~150 μ m/h, obtains the plating sheet material of thickness 〉=0.5mm; Electroplate sheet material and never become rusty and take off on the steel plate, in the isostatic sintering stove, handle, 930 ℃ of sintering temperatures, pressure 6~9MPa, protective atmosphere are nitrogen, argon gas, temperature retention time 2~3h; That plating sheet material after the sintering processes carries out is cold rolling, blanking makes contact.
The preparation method is as follows for the silver-nickel electroplate liquid: the silver powder that takes by weighing aequum is dissolved in the nitric acid, makes liquor argenti nitratis ophthalmicus, and silver powder should be excessive a little, filters standby; The potassium cyanide that takes by weighing aequum is dissolved in makes potassium cyanide solution in the distilled water, then potassium cyanide solution is added in the liquor argenti nitratis ophthalmicus, obtains white silver cyanide sediment, sediment undergoes washing is filtered standby; The potassium cyanide that takes by weighing aequum is dissolved in to be made potassium cyanide solution and adds the silver cyanide sediment in the distilled water, make silver-colored cyaniding and test potassium solution; The potash that takes by weighing aequum is dissolved in the distilled water, adds silver-colored potassium cyanide solution then, adds nickel cyanide solution in proportion again, and adding distil water dilutes, and obtains described silver-nickel electroplate liquid.
Because this silver based contact material contains carbon 0.1~2.0%, yttria 0.1~15%, nickel 5.0~50%, therefore on serviceability, has the advantage of silver/nickel, silver/oxide, three kinds of contact materials of silver/carbon, it connects performance and silver/carbon, silver/nickel contact material is suitable, anti-interrupting performance and silver/carbon contact material is suitable, and arc resistant scaling loss performance and silver/oxide contact tip material are suitable.
The production characteristics of this silver based contact material are: adopt the composite alloy electric plating method, deposition contact material sheet material on corrosion resistant plate takes off then that sintering makes it to reach densification in the isostatic sintering stove, carries out cold rolling, blanking then and makes contact.When electroplating, use the silver-nickel electroplate liquid, adding rare earth oxide yttria and carbon (graphite or diamond) ultra micro powder carry out composite plating in electroplate liquid.Can control the composition of various materials easily with the method, and the disperse in silver matrix of each component evenly distributes, it is similar to the distribution of particles of the contact material of internal oxidation production to observe the distribution of each particle in silver by metallographic structure, and in contact distributed throughout unanimity.Can obtain the material of the different silver content of each layer of contact by silver and nickel ion or silver plate in the control solution and the ratio of nickel plate area, the bottom of coating can be in the electroplate liquid that does not have oxide and carbon at first plating obtain the good weld layer of welding performance.In the electroplate liquid that oxide and carbon are arranged, be electroplated onto desired thickness then, take off the back and in the isostatic sintering stove, under hyperbar, carry out the sheet material that sintering obtains densification, obtain various contacts by following process.
Four, embodiment
Below in conjunction with embodiment the present invention is explained in detail again.
Embodiment one:
A kind of silver/nickel/rare earth oxide/carbon contact, the composition proportion of its material are (percentage by weight): carbon 0.4, yttria 3.0, nickel 5.0, silver-colored surplus.
Production method:
(1) electroplate liquid preparation: prepare 10 liters of electroplate liquids-take by weighing 250 and restrain silver powder and be dissolved in the nitric acid, make liquor argenti nitratis ophthalmicus (silver powder should be excessive a little), filter standby.Taking by weighing potassium cyanide 70 gram is dissolved in and makes potassium cyanide solution in the distilled water.Then potassium cyanide solution is added in the liquor argenti nitratis ophthalmicus, obtain white silver cyanide sediment, sediment undergoes washing is filtered standby.Take by weighing potassium cyanide 220 gram and be dissolved in and make potassium cyanide solution in the distilled water and add the silver cyanide sediment, make silver-colored cyaniding and test potassium solution.Take by weighing potash 100 gram and be dissolved in the distilled water, add silver-colored potassium cyanide solution then, add nickel cyanide solution in proportion again, with this solution adding distil water be diluted to 10 liters standby.
(2) electroplate: the thickness of corrosion resistant plate is 0.5~1.0mm, uses the sulfuric acid passivation, cleans up then.In electroplate liquid, add yttria (granularity is 2~4 μ m) and carbon (graphite or diamond, granularity are 0.1~1.5 μ m).Use silver plate and nickel plate as anode then, stainless steel is as negative electrode, and cathode-current density is 1.5~3.0A/dm
2Electroplating current adopts the DC power supply or the pulse power (the most handy pulse power,, negative electrode is used the plastics mold and is shielded, and solution needs with stirring during plating, plating bath is through outside the general plating solution maintenance, content to the suspended matter of plating bath is monitored, and regularly replenishes, and electroplating velocity is 50~150 μ m/h, obtain the plating sheet material of thickness 〉=0.5mm, make coating that certain intensity be arranged.
(3) the plating back is checked:
A. composition inspection: carbon 0.4~0.5%, yttria 3.0~3.5%, nickel 5.0~5.5% (percentage by weight);
B. metallographic examination: distribution of particles is even, and the gathering greater than 10 μ m can not be arranged.
(4) high-temperature process: electroplate sheet material and never become rusty and take off on the steel plate, in the isostatic sintering stove, handle, 930 ℃ of sintering temperatures, pressure 6~9MPa, protective atmosphere nitrogen, argon gas, temperature retention time 2~3h, thus improve its intensity and density.
(5) rolling: the plating sheet material after the sintering processes carries out the cold rolling thickness that obtains requiring.
(6) blanking: make corresponding contact through the punch press blanking.Residue rim charge after the punching out can be used as anode and utilizes, thereby has improved the utilization rate of material, has reduced the cost recovery of material.
(7) high temperature is handled again: make corresponding contact through the punch press blanking, in the isostatic sintering stove, handle, 930 ℃ of sintering temperatures, pressure 6~9MPa, protective atmosphere nitrogen, argon gas, temperature retention time 2~3h, from and improve its intensity and density.
Embodiment two:
A kind of silver/nickel/rare earth oxide/carbon contact, the composition proportion of its material are (percentage by weight): carbon 1.0, yttria 15, nickel 50, silver-colored surplus.
Production method is with embodiment one, composition inspection: carbon 1.0~1.2%, yttria 14.5~15%, nickel 48~50% (percentage by weight).
Embodiment three:
A kind of silver/nickel/rare earth oxide/carbon contact, the composition proportion of its material are (percentage by weight): carbon 0.7, yttria 9, nickel 18, silver-colored surplus.
Production method is with embodiment two, composition inspection: carbon 0.6~0.8%, yttria 8.5~9.5%, nickel 17~19% (percentage by weight).