The object of the present invention is to provide a kind of contact material that is applicable to that vacuum load switch needs, i.e. vacuum load switch contact material and manufacture method thereof.This contact material is anti-ablative good with resistance fusion welding, the dielectric strength height, and shut off value is low, and gas content is low, has certain short circuit current ability of cut-offfing, and can satisfy the requirement of vacuum load switch well.
At above-mentioned purpose, vacuum load switch contact material of the present invention is made by the tungsten copper infiltrated alloy.
The chemical composition of tungsten copper infiltrated alloy (weight %) is:
W85~93%, copper or copper alloy 7~15%, wherein the chemical composition of copper alloy (weight %) is:
Cu90~99.9%, any or any two above sum 0.1~10% among Bi, Te, Sb, Pb, Se, the Sn.
Tungsten of the present invention is our refractory metal element, has the good high-temperature performance, tungsten powder tungsten particle behind high temperature sintering is coupled to the W skeleton (seeing accompanying drawing 1) that has than high bond strength, and a spot of copper is uniformly distributed in and (sees accompanying drawing 2) in the W skeleton, thereby guarantee that contact has characteristics such as good anti-ablation, anti-melting welding, high pressure resistant and low shut off value, can adapt to the requirement of vacuum load switch fully.
The manufacture method of vacuum load switch contact material of the present invention, comprise get the raw materials ready, press forming, the presintering of tungsten powder blank, sintering and ooze copper process, existing division is as follows:
One, gets the raw materials ready
Tungsten, copper or copper alloy raw material all adopt Powdered, wherein, and granularity requirements 1~10 μ m of tungsten powder, and according to chemical composition proportioning is got the raw materials ready.
Two, press forming
Press forming has two kinds of methods: the one, and cold isostatic compaction; The one, mechanical die forming,
(1) cold isostatic compaction is packed tungsten powder in the soft mode cover into, and puts into and be pressed into the tungsten powder blank in the cold isostatic press, and its forming pressure is 100~200MPa.
(2) mechanical die forming is pressed into the tungsten powder blank with tungsten powder on the mould of hydraulic press or punching machine, and it is 60~150MPa that institute exerts pressure,
When adopting mechanical die forming, need in tungsten powder, to add binder 0.1~4.0 (weight %), its binder be in alcohol, acetone, glycerine, polyvinyl alcohol, oleic acid, paraffin wax, rubber, the stearate any.
Binder is when getting the raw materials ready, and adds in the tungsten powder.The purpose that adds binder is in order to improve the forming property of tungsten material base material.
(3) mechanical die forming tungsten powder blank presintering
The presintering of the tungsten powder blank of machinery die forming divides two stages to carry out:
Phase I presintering: 400~800 ℃ of temperature, 2~6 hours time;
Second stage presintering: 1000~1300 ℃ of temperature, 0.5~3.0 hour time.
Above-mentioned phase I presintering purpose is in order fully to remove binder; The purpose of second stage presintering is in order further to improve the intensity of tungsten powder blank.
Through the tungsten powder blank of cold isostatic compaction, need not to carry out presintering, can directly carry out sintering.
(4) tungsten powder blank sintering
Place the sintering furnace of hydrogen shield or vacuum to carry out sintering with the tungsten powder blank of cold isostatic compaction with through the mechanical die forming tungsten powder blank of presintering, sintering temperature is 1800~2400 ℃, and sintering time is 1~5 hour;
The tungsten powder blank can be removed impurity effectively behind sintering under high-temperature hydrogen protection or the vacuum, improve material purity, has reduced gas content, its gas and be mingled with low 5~10 times of the general contact material of content, and total amount is less than 10PPm.
In addition,, the purity of W skeleton is improved, guarantee carrying out smoothly of infiltration, make this contact material more even, fine and close through high-temperature hydrogen protection sintering.
The tungsten powder blank promptly becomes the W skeleton with higher-strength behind sintering.
(5) W skeleton oozes copper
W skeleton put into ooze the copper stove and ooze copper, oozing the copper temperature is 1150~1300 ℃, oozes 0.5~3.5 hour copper time, oozes the copper process and carries out under hydrogen atmosphere or vacuum.
W skeleton promptly becomes vacuum load switch contact material goods of the present invention after oozing copper or copper alloy.This material homogeneity is good, no hole, and relative density reaches more than 99.0%, and the height of anti-intensity, and anti-ablation and resistance fusion welding can be good, and shut off value is low, conductance is high, is that 10% o'clock conductance is greater than 20m/ Ω mm as copper content
2, be specially adapted to make the vacuum load switch contact.
Compared with prior art, the present invention has following advantage:
(1) anti-ablative good with resistance fusion welding.Because the present invention has reduced the copper content in the existing tungsten copper contact material, make tungsten particle form continuous W skeleton with higher-strength, low melting-point coper or copper alloy fix in the capillary of W skeleton, reduced the splash of the low melting point phase under the electric arc, improve the anti-galvano-cautery performance of contact widely, thereby guaranteed the anti-ablation of contact, the characteristic of anti-melting welding.
(2) shut off value is low.Because W skeleton forms network, has stoped the energy loss under the little arc current, improve the evaporation capacity of copper or copper alloy phase, when cut-offfing little electric current, can provide enough metal vaporss, stablizing of pilot arc reduces shut off value.Add a small amount of low melting point constituent element in the copper alloy that is oozed, help further to reduce shut off value.
(3) compressive resistance height, contact resistance is little.Contact material of the present invention, hardness is moderate, Brinell hardness HB is 220~260, just in time satisfied the requirement of on-load switch, moderate hardness number, both guarantee withstand voltage requirement, and avoided too high spring that causes of hardness and contact resistance to raise again, improved the rated operational current and the dynamic thermal stability of vacuum switch greatly.
(4) purity height, impurity content is low, insulate after helping improving arc, thereby improves connecting-disconnecting function and vacuum load switch tube lifetime.Through high-temperature hydrogen protection sintering, can remove impurity and gas effectively, improve material purity.
(5) good uniformity, no hole, relative density reaches more than 99.0%, helps improving the combination property of material.
Now the invention will be further described in conjunction with the accompanying drawings.