A kind of method of making fine copper/chromiumcopper composite contact materialTechnical field:
The invention belongs to the metal material technical field, be specifically related to a kind of method of making fine copper/chromiumcopper composite contact material.
Background technology:
Contact is the key element of vacuum circuit-breaker, and desirable vacuum contact material should have following performance: 1. high electric current breaking capacity; 2. the high voltage capability of bearing; 3. high conductance and thermal conductivity; 4. resistance fusion welding can be good; 5. low electrical arc erosion rate; 6. low contact wearing and tearing; 7. low shut off value; 8. good processing properties.Because between these performances is conflicting, in actual application, often receives the influence of various factors, and can not satisfy above each item index simultaneously.
According to the performance requirement of vacuum contact material, though fine copper possesses high conductance and thermal conductivity and good processing properties, mechanical strength is low, resistance to wears, anti-galvanic corrosion and resistance fusion welding be poor, is used to make vacuum contact material, and it obviously shows the deficiency of self.
In order to improve the resistance to wearing of fine copper, anti-galvanic corrosion and resistance fusion welding and mechanical strength, people improve its performance through alloyage process, wherein mainly contain W-Cu, Cu-Bi and Cu-Cr series alloy as contact material.Along with the development of high-power vacuum high-voltage switch technology, the alloy contact of Cu-Cr series has much with its numerous superior function and replaces W-Cu, the gesture of the alloy contact material of Cu-Bi series in recent years.The advantage of Cu-Cr alloy contact material is to have very little mutual solubility between Cu and the Cr; Visible by the Cu-Cr alloy phase diagram; Almost insoluble when only having 0.7%, 600 ℃ during 1080 ℃ of the solid solubility of Cr in Cu, thus make Cu and Cr all fully keep good separately performance; That is: have Cu constituent element, help improving the breaking capacity of vacuum switch than low melting point, high conductivity and thermal conductivity; The Cr constituent element has high melt point, can impel the alloy substrate grain refinement, helps forming stable hardening constituent even, that disperse distributes, can keep the high conductivity of material, can improve its connecting-disconnecting function and mechanical property again, and is difficult for producing thermionic emission.This material can guarantee that vacuum switch has characteristics such as good proof voltage, anti-scorching, anti-melting welding and low dams.
Yet,, thereby adopt the Cu-Cr alloy gross segregation of common method of smelting preparation serious because the Cu-Cr alloy belongs to the alloy of difficult miscible series.In order to address this problem, countries in the world prepare the Cu-Cr alloy and mainly adopt powder metallurgic method, infiltration method and vacuum arc melting method.Though the Cu-Cr series alloy of these method preparations has been used to contact material, all has the shortcoming and defect of self.Wherein the major defect of powder metallurgic method is that size and spacing between the Cr particle is excessive, and the structural homogenity of material is lower, and oxygen and nitrogen content are too high, have reduced the breaking capacity of contact electric current.The shortcoming of infiltration method is that production efficiency is low, and the chromium particle is relatively thick, and chromium content must reach suitable ratio, and this has seriously reduced conductance.And the arc melting method production cost is higher, and much technological parameter need further be groped and be perfect.Generally speaking, being added in when improving the contact partial properties of Cr element in the copper must weaken other performance, is cost to reduce conductive capability promptly.
At present; The high-power Cu-Cr contact thickness that uses is generally 3-6mm; And the wearing and tearing of contacts of vacuum switch and galvanic corrosion mainly occur in the surface, and promptly vacuum contact has the thick Cu-Cr layer of 0.8-1.2mm can satisfy instructions for use, if can be used as vacuum contact material at the thick Cu-Cr alloy-layer of fine copper surface preparation 0.8-1.2mm; Not only can make full use of fine copper and Cu-Cr alloy advantage performance separately, and manufacturing cost is significantly reduced.
Summary of the invention:
The objective of the invention is advantage and deficiency to whole fine copper and Cu-Cr alloy; And a kind of method of making fine copper/chromiumcopper composite contact material is provided, specifically, be resistance to wear at the fine copper surface laser cladding, method that anti-galvanic corrosion and resistance fusion welding and the excellent Cu-Cr alloy of mechanical strength are made the Cu/Cu-Cr composite contact material; It promptly is basic material with the fine copper; The Cu-Cr mixed powder for alloy is a clad material, adopts laser cladding method, under argon shield; The cladding of Cu-Cr alloy powder coating on the fine copper substrate surface, is formed fine copper/Cu-Cr alloy composite materials.Adopt this method; Can obtain the good alloy-layer of wear resistant anti-electric corrosion on the fine copper surface; Its heart portion keeps the good electric conductivity of fine copper, and the surface fully represent the high electric current breaking capacity of Cu-Cr alloy, high bear voltage capability, good resistance fusion welding can, low electrical arc erosion rate and low performance characteristics such as contact wearing and tearing.
Technical scheme of the present invention realizes by following mode:
A kind of method of making fine copper/chromiumcopper composite contact material may further comprise the steps:
The first step, the fine copper substrate surface earlier use sand papering, use acetone surperficial again;
Second step, the chromiumcopper coating presets: with copper powder and chromium powder by weight percentage: the mixed of Cu 60-85%, Cr15-40% is even; Coating presets the employing bonding method; The volume ratio of binding agent and Cu-Cr powder is 1: 1.6-2, and add acetone diluted again and be modulated into pasty state, preset the Cu-Cr coating that thickness is 1.2-1.8mm at the fine copper substrate surface; Placing baking oven, is to dry under the 80-100 ℃ of condition at bake out temperature;
The 3rd step, coating is carried out laser melting coating: laser melting coating equipment adopts the multi-functional CO of 5kW2Cross-flow laser, laser technical parameters is: laser output power 1.5-2.5kW, sweep speed 6-15mm/s, spot diameter 3mm, the single track cladding, the overlapping rate of multi-track overlapping cladding is 30-45%, uses the argon shield molten bath in the laser cladding process;
The 4th goes on foot, fine copper/chromiumcopper cladding layer is flattened process and polishing.
Be meant with sand papering in the described step (), polished with 400-600 sand paper in fine copper substrate surface position to be plated,, help the bonding of preset coating so that make surface cleaning and possess certain roughness.
Be meant with acetone in the described step (), clean the fine copper substrate surface, except that reaching the oil removing purpose, also help the wetting coating of preset coating with acetone.
Binding agent in the described step (two) is commercially available HZ-504 adhesive.
The copper powder in the described step (two) and the granularity of chromium powder are-200 orders.
Laser technical parameters in the described step (three) is preferred: laser output power 1.8-2.2kW, sweep speed 8-12mm/s, the overlapping rate of multi-track overlapping cladding are 33-40%.
Good effect of the present invention is:
1, the present invention has overcome the Cu-Cr alloy gross segregation serious problems of common method of smelting preparation, and the disperse of Cr distribution of particles is even in the coating; Overcome the deficiency of powder metallurgical sintering process voidage higher (10%-30%) and air-breathing rate height and complex procedures, coating dense structure and operation are simple and direct; It is low to have overcome infiltration method production efficiency, and the chromium particle is relatively thick, and chromium content must reach the shortcoming of suitable ratio (being generally 50%), has guaranteed excellent conductivity and thermal conductivity.
2, cladding layer of the present invention is the Cu-Cr alloy, and main component is a copper, with the base material fine copper close physical parameter is arranged, and affinity is good, and base material little melting is taken place, coating/base material bond strength height.
3, the contact tip composite material of the present invention's manufacturing; Heart portion keeps the good electric conductivity of fine copper; The surface possess the high electric current breaking capacity of Cu-Cr alloy, high bear voltage capability, good resistance fusion welding can, low electrical arc erosion rate and low combination properties such as wear rate, can also save the higher relatively chromium resource of price.
Embodiment:
Below in conjunction with embodiment the present invention is done further detailed description.
Embodiment 1:
Thickness is the fine copper sheet material of 2mm, and length and width is of a size of 20mm * 40mm, and at its surface laser cladding layer of copper chromium alloy layer, its processing step is:
The first step, elder generation polish with the 400-600 emery cloth to fine copper substrate surface position to be plated, use the acetone surface again;
Second step, chromiumcopper coating preset: copper powder and 80: 20 by weight percentage mixed of chromium powder is even; Coating presets the employing bonding method; Be about to commercially available HZ-504 adhesive and mixed in 1: 1.6 by volume, add acetone diluted and be modulated into pasty state, preset the Cu-Cr coating that thickness is 1.2-1.4mm at the fine copper substrate surface with the Cu-Cr powder; Placing baking oven, is to dry under 80 ℃ of conditions at bake out temperature;
The 3rd the step, coating is carried out laser melting coating, laser technical parameters is laser output power 1.5kW, sweep speed 8mm/s, spot diameter 3mm, the single track cladding, the overlapping rate of multi-track overlapping cladding is 33%.Use the argon shield molten bath in the laser cladding process;
The 4th goes on foot, fine copper/chromiumcopper cladding layer is flattened process and polishing.
Embodiment 2:
Thickness is the fine copper sheet material of 3mm, and length and width is of a size of 15mm * 45mm, and at its surface laser cladding layer of copper chromium alloy layer, its processing step is:
The first step, elder generation polish with the 400-600 emery cloth to fine copper substrate surface position to be plated, use the acetone surface again;
Second step, chromiumcopper coating preset: copper powder and 75: 25 by weight percentage mixed of chromium powder is even; Coating presets the employing bonding method; Be about to commercially available HZ-504 adhesive and mixed in 1: 1.8 by volume, add acetone diluted and be modulated into pasty state, preset the Cu-Cr coating that thickness is 1.3-1.5mm at the fine copper substrate surface with the Cu-Cr powder; Placing baking oven, is to dry under 90 ℃ of conditions at bake out temperature;
The 3rd the step, coating is carried out laser melting coating, laser technical parameters is: laser output power 1.8kW, sweep speed 10mm/s, spot diameter 3mm, the single track cladding, the overlapping rate of multi-track overlapping cladding is 36%.Use the argon shield molten bath in the laser cladding process;
The 4th goes on foot, fine copper/chromiumcopper cladding layer is flattened process and polishing.
Embodiment 3:
Thickness is the fine copper sheet material of 4mm, and length and width is of a size of 25mm * 50mm, and at its surface laser cladding one deck Cu-Cr alloy-layer, processing step is:
The first step, elder generation polish with the 400-600 emery cloth to fine copper substrate surface position to be plated, use the acetone surface again;
Second step, the chromiumcopper coating presets: with copper powder and chromium powder by weight percentage: 70: 30 mixed is even; Coating presets the employing bonding method; Be about to commercially available HZ-504 adhesive and mixed in 1: 2 by volume, add acetone diluted and be modulated into pasty state, preset the Cu-Cr coating that thickness is 1.4-1.6mm at the fine copper substrate surface with the Cu-Cr powder; Placing baking oven, is to dry under 100 ℃ of conditions at bake out temperature;
The 3rd the step, coating is carried out laser melting coating.Laser technical parameters is laser output power 2.0kW, sweep speed 12mm/s, and spot diameter 3mm, the single track cladding, the overlapping rate of multi-track overlapping cladding is 40%.Use the argon shield molten bath in the laser cladding process.
The 4th goes on foot, fine copper/chromiumcopper cladding layer is flattened process and polishing.