JP3809435B2 - Electrode material for EDM - Google Patents

Description

  The present invention relates to an electrode material for electric discharge machining, but does not include an electrode material for a cut wire for wire electric discharge machining, and relates to an electrode material for a machining electrode mainly used for die-sinking electric discharge machining.

  In electric discharge machining, it has been desired that the machining speed of the workpiece is high and that the electric discharge machining electrode itself is less consumed. At the same time, the surface state of the electrode for electric discharge machining is transferred to the workpiece, so that there is no nest on the surface or inside of the electrode for electric discharge machining, or the size of the nest is as small as possible (depending on the purpose of use) However, for example, 4 μm or less) has been desired.

  In order to satisfy such a demand, various electrode materials for electric discharge machining have been researched and developed. Among them, the W-Cu alloy and the W-Ag alloy take advantage of the high melting point and boiling point of W and the high thermal conductivity and electrical conductivity of Cu or Ag to reduce the consumption of the electrodes. Has been used as an electrode material suitable for electric discharge machining, particularly as an electrode for electric discharge machining suitable for precision machining applications and carbide-type electric discharge machining applications.

  Regarding the electric discharge machining electrode made of these W-Cu alloy and W-Ag alloy, since there is a strong demand for efficiency improvement at the actual electric discharge machining site, the consumption of the electrode is further reduced, and the machining speed is further improved. Improvement of electric discharge machining characteristics has been studied.

  Specific examples thereof include alkali metal elements such as Na and K, Sr and Ca in an alloy such as W-Cu, as described in JP-A-63-195242 and JP-A-50-109595. An electrode material for electric discharge machining has been developed in which the work function of an alloy is reduced and the machining speed is improved by adding alkaline earth metal elements such as these or oxides thereof.

  However, the W-Cu alloy electric discharge machining electrode containing an alkali metal element, an alkaline earth metal element, or an oxide thereof certainly has a low work function and can improve the processing speed. Electrical discharge machining characteristics are not always sufficient, and in particular, further improvement and improvement in electrode wear resistance and machining speed have been desired. In addition, some of the metal components to be added are toxic or hygroscopic, so that they are inconvenient to handle and difficult to manufacture.

JP-A-63-195242 Japanese Patent Laid-Open No. 50-109595

  In view of such conventional circumstances, the present invention is an electrode material for electric discharge machining made of a W-Cu alloy, which consumes less electrode and has a higher machining speed than conventional ones, and has excellent electric discharge machining characteristics. An object of the present invention is to provide an electrode material.

  However, the present invention mainly provides an electrode material made of a W-Cu alloy for die-sinking electric discharge machining, and does not target electrodes for wire electric discharge machining, so-called cut wires. The cut wire is mainly made of pure Cu or pure W, whereas the electrode material of the present invention is made of a W—Cu alloy, which differs in composition and manufacturing method. In addition, for the purpose of use, it is necessary to reduce the straightness of the wire, the strength at high temperature, and the number of breaks of the cut wire in addition to the processing speed, but the present invention does not aim at these. .

  In order to achieve the above object, the present inventors have studied the discharge phenomenon in detail through trial manufacture of a W-Cu alloy and its evaluation. As a result, it was found that the discharge phenomenon is not stable because the W—Cu alloy is composed of a Cu portion and a W portion. That is, since the physical characteristics such as thermal conductivity are different between Cu and W, the arc behavior has become unstable due to local non-uniformity in the W-Cu alloy composition.

  In order to solve this problem, as a result of intensive studies on various additive elements and compounds thereof, elements having a small work function such as alkali metal elements, alkaline earth metal elements, rare earth elements, or oxides of these elements It has been found that by adding hydroxide, nitride, boride, sulfide, etc. and reducing the average particle size, the arc behavior is stabilized. As a result of stabilizing the arc behavior and facilitating the electric discharge phenomenon, it was confirmed that the wear resistance rate of the electrode was improved and at the same time the electric discharge machining speed was improved, and the present invention was achieved.

  That is, the first electrode material for electric discharge machining provided by the present invention is a W-Cu alloy comprising 40 wt% or more of W, 15 wt% or less of an additive element or a compound thereof, and the balance Cu. As the additive element or a compound thereof, at least one selected from alkali metal elements, alkaline earth metal elements, rare earth elements, and oxides, hydroxides, nitrides, borides, and sulfides of these elements is 10 It is characterized by containing no more than wt% and having an average particle size of less than 3 μm.

  In addition, instead of reducing the particle size of the additive element having a small work function, such as an alkali metal element, alkaline earth metal element, rare earth element, or a compound thereof added to the WC alloy, the interval between these particles is changed. It has been found that the same effect can be obtained by reducing the distance between certain particles. In general, when fine powder is used, the distance between particles tends to be small, but the same effect can be expected when the distance between particles can be small even if the particles are large.

  Based on this knowledge, the second electrode material for electric discharge machining provided by the present invention is a W—Cu alloy comprising 40 wt% or more of W, 15 wt% or less of an additive element or a compound thereof, and the balance of Cu. The additive element or compound thereof is at least one selected from alkali metal elements, alkaline earth metal elements, rare earth elements, and oxides, hydroxides, nitrides, borides, and sulfides of these elements. It contains 10% by weight or less of seeds, and the average interparticle distance of the particles is 20 μm or less.

  In addition, the characteristics of the first and second electrode materials for electric discharge machining of the present invention can be combined. That is, the third electrode material for electric discharge machining provided by the present invention is a W-Cu alloy comprising 40 wt% or more of W, 15 wt% or less of an additive element or a compound thereof, and the balance Cu. As the additive element or a compound thereof, at least one selected from alkali metal elements, alkaline earth metal elements, rare earth elements, and oxides, hydroxides, nitrides, borides, and sulfides of these elements is 10 The average particle diameter of the particles is less than 3 μm, and the average interparticle distance is 20 μm or less.

  Each of the electrode materials for electric discharge machining of the present invention is selected from the alkali metal elements, alkaline earth metal elements, rare earth elements, and oxides, hydroxides, nitrides, borides, and sulfides of these elements. The at least one kind of particles preferably has an average particle size of less than 1 μm. Further, in each electrode material for electric discharge machining of the present invention, the alkali metal element, alkaline earth metal element, rare earth element, and oxides, hydroxides, nitrides, borides, and sulfides of these elements. The at least one selected particle preferably has an average interparticle distance of 10 μm or less.

  Further, it has been found that the same effect can be obtained even when the particle size of some of the additive elements or the compounds thereof is small. That is, the fourth electrode material for electric discharge machining provided by the present invention is a W-Cu alloy comprising 40 wt% or more of W, 15 wt% or less of an additive element or a compound thereof, and the balance Cu. As the additive element or a compound thereof, at least one selected from alkali metal elements, alkaline earth metal elements, rare earth elements, and oxides, hydroxides, nitrides, borides, and sulfides of these elements is 10 It is characterized in that it contains 0.3% by weight or more of the whole alloy containing particles of 3% by weight or less with a particle size of 3% or less.

  In the fourth electric discharge machining electrode material of the present invention, the alkali metal element, alkaline earth metal element, rare earth element, and oxides, hydroxides, nitrides, borides, and sulfides of these elements. It is at least one selected and contains particles having a particle size of 3 μm or less of 0.6% by weight or more of the whole alloy, or particles having a particle size of 1 μm or less of 0.3% by weight of the whole alloy. It is preferable to include the above.

  Furthermore, it has been found that the same effect can be obtained even when the distance between some of the particles of the additive element or the compound thereof is small. That is, a fifth electric discharge machining electrode material provided by the present invention is a W-Cu alloy comprising 40 wt% or more of W, 15 wt% or less of an additive element or a compound thereof, and the balance Cu. As the additive element or a compound thereof, at least one selected from alkali metal elements, alkaline earth metal elements, rare earth elements, and oxides, hydroxides, nitrides, borides, and sulfides of these elements is 10 It is characterized in that it contains 0.3% by weight or more of the whole alloy containing particles of not more than% by weight and having an interparticle distance of 20 μm or less.

  In the fifth electric discharge machining electrode material of the present invention, the alkali metal element, alkaline earth metal element, rare earth element, and oxides, hydroxides, nitrides, borides, and sulfides of these elements. It is preferable that at least one selected particle having an interparticle distance of 10 μm or less is contained in an amount of 0.3% by weight or more of the whole alloy, and more preferably 0.7% by weight or more of the whole alloy.

  In each of the above-described electrode materials for electric discharge machining of the present invention, the alkali metal element, alkaline earth metal element, rare earth element, and oxides, hydroxides, nitrides, borides, and sulfides of these elements are selected. The at least one kind of particles preferably exist in Cu. Similarly, at least one particle selected from the alkali metal elements, alkaline earth metal elements, rare earth elements, and oxides, hydroxides, nitrides, borides, and sulfides of these elements is W It is preferably present partially in the particles.

  Further, in each of the electrode materials for electric discharge machining of the present invention described above, the alkali metal element, alkaline earth metal element, rare earth element, and oxides, hydroxides, nitrides, borides, and sulfides of these elements. Is preferably Ba, Nd, Ce, Y, Ca, K, or an oxide or hydroxide thereof. Moreover, the case where W particle | grains contain K may be sufficient. For example, K may be doped in W. In addition to K, other elements such as Al may be doped together with K.

  Furthermore, in each of the electrode materials for electric discharge machining of the present invention described above, it is preferable that the W has a particle size of 1 μm or less of 30% by weight or more of the total W particles. Further, in place of a part of the Cu, it may further contain 10% by weight or less of Ni.

  In the present invention, the method for measuring the particle size of W particles in the W—Cu alloy is performed as follows. An arbitrary cross section of the alloy is photographed at a magnification of 1500 by scanning electron microscope observation, and this is magnified by 4 times with a copying machine. A line segment having a length of 20 cm is arbitrarily drawn in the enlarged photograph, and the intersecting length of the W particles intersecting with the line segment is measured. This operation is repeated until the number of measurements reaches 500, and the average value of the 500 measurement lengths is taken as the average particle diameter of the W particles.

  Also, the particles of alkali metal elements, alkaline earth metal elements, rare earth elements, or oxides, hydroxides, nitrides, borides, and sulfides of these elements contained in the W-Cu alloy The diameter is measured by scanning electron microscope observation of an arbitrary cross section of the alloy as in the case of the W particles. However, the particle diameter is measured with a photograph taken at a magnification of 5000 times, and an average value of 500 arbitrary particles is taken as the average particle diameter of the particles. Further, the interparticle distance of each particle is obtained by measuring the distance from an arbitrary particle to the nearest particle, and the average value of the arbitrary 500 particles is defined as the average interparticle distance of the particles.

  In addition, as a method of measuring the particle size of the particles, so-called surface analysis is performed. That is, the diameter of the white spot particle detected by the surface analysis is measured, and the characteristic X is picked up in consideration of the error portion in the analysis, that is, from the region where the electron beam is applied for the analysis. Assuming that the area of the sample surface is expanded by about 1.5 μm, the particle size is determined by subtracting 3 μm from the measured value of vitiligo spots. For example, if the measured value of vitiligo spots is 6 μm, the particle size is calculated to be 3 μm. If the white spot is less than 3 μm, it is considered to be a small particle having a particle size of less than 1 μm. In addition, in the case of observing an elliptical shape, the particle size is obtained by measuring the minor axis. The average particle diameter is obtained by arithmetically averaging the particle diameters thus obtained.

  According to the present invention, with respect to an electrode material for electric discharge machining made of a W-Cu alloy, it is possible to reduce electrode consumption and increase the machining speed as compared with the prior art, mainly die-cut electric discharge machining excellent in electric discharge machining characteristics. It is possible to provide an electrode material for electric discharge machining used in the above.

  The W—Cu alloy in the electrode material for electric discharge machining according to the present invention basically comprises 40% by weight or more of W and the balance of Cu, and contains 15% by weight or less of an additive element or a compound thereof. In particular, in an electrode for die-sinking electric discharge machining, it is desirable that the W concentration is 60 to 80% by weight in consideration of electric discharge machining characteristics and ease of manufacture. In addition to the above, this W-Cu alloy contains unavoidable impurities.

  The electrode material for electric discharge machining of the present invention is an alkali metal element, an alkaline earth metal element, a rare earth element, or an oxide, hydroxide, or nitride of these elements as an additive element of the W-Cu alloy or a compound thereof. , Borides and sulfides. The content of these essential additive elements or additive compounds is 10% by weight or less, preferably in the range of 0.5 to 5% by weight. When the content of the additive element and the compound exceeds 10% by weight, the machinability of the electric discharge machining electrode itself is deteriorated, which is not preferable. The total amount of additive elements and compounds contained in the W-Cu alloy including these essential additive elements or additive compounds is 15% by weight or less.

  The above-mentioned essential additive elements or additive compounds, that is, alkali metal elements, alkaline earth metal elements, rare earth elements, or oxides, hydroxides, nitrides, borides, and sulfides thereof as particles in the W-Cu alloy. Exists. The average particle size of these particles needs to be less than 3 μm, more preferably less than 1 μm. When the average particle size of the particles is 3 μm or more, the electrical discharge machining characteristics are deteriorated, and particularly the wear resistance of the electrode is remarkably reduced.

  In addition, the above-mentioned essential additive elements or additive compounds such as alkali metal elements, alkaline earth metal elements, rare earth elements, or oxides thereof have improved electrical discharge machining characteristics by reducing the average interparticle distance. As a result, the wear resistance of the electrode is improved. The average interparticle distance of these particles is preferably as small as possible, specifically 20 μm or less, and preferably 10 μm or less. This is because if the average interparticle distance exceeds 20 μm, the effect of improving the electrode wear resistance and processing speed characteristics is poor.

  In addition, for the particles of the above essential additive element or additive compound, the electrical discharge machining characteristics are improved and the electrode wear resistance is improved if the particle diameter is small even if it is a part of the particles, not the average particle diameter. Can be made. In that case, among these particles, particles having a particle size of 3 μm or less are required to be contained in an amount of 0.3% by weight or more of the whole alloy, and are contained in an amount of 0.6% by weight or more of the whole alloy. Preferably it is. Similarly, among these particles, a particle having a particle size of 1 μm or less is preferably contained in an amount of 0.3% by weight or more of the entire alloy.

  In addition, for the particles of the above essential additive element or additive compound, the electrical discharge machining characteristics are improved and the electrode wear resistance is improved if the interparticle distance is small even if part of the particles, not the interparticle distance. Can be made. In that case, among these particles, it is necessary that particles having an interparticle distance of 20 μm or less are contained in an amount of 0.3% by weight or more of the entire alloy. Furthermore, it is preferable that the particle | grains whose particle distance is 10 micrometers or less are contained 0.3 weight% or more of the whole alloy, and it is still more preferable that 0.7 weight% or more of the whole alloy is contained.

  As a method for reducing the particle size and the distance between particles of alkali metal element, alkaline earth metal element, rare earth element, or a compound thereof, a powder having a small particle size is used as the raw material powder, or the raw material powder The method of increasing the mixing time is simple and preferable. For example, the normal mixing time is about 5 hours. By setting the mixing time to 3 times or more, the dispersion of the particles can be improved, and the average interparticle distance can be made 20 μm or less. The average interparticle distance can also be reduced by increasing the concentration of the essential additive element or additive compound.

  Further, as a method for obtaining a fine and uniform dispersed state of particles, it is effective to use a coprecipitation method or a so-called mechanical alloying method when mixing the raw material powder. The mechanical alloying method is particularly effective, and it may be a wet type that contains a small amount of an organic solvent such as alcohol as a solvent, or a dry type that does not contain a solvent. Is done dry. Usually, it is carried out in an Ar gas atmosphere, with the moisture and organic solvent removed. Oxygen and nitrogen are usually harmful, and when these concentrations are high, the effect of mechanical alloying is small. The mechanical alloying method is not a simple powder mixing method, but a method in which each powder particle is made into an alloy powder composed of a blended powder seed after the mixing stage. It is usually used as a method for producing a heat-resistant alloy or as a method for obtaining an amorphous powder. As a result of intensive studies, the present inventors have found that this method is effective in improving the electric discharge machining characteristics. Specifically, by means of an attritor, vibration mill, ball mill, etc., together with W powder and Cu powder, alkali metal elements, alkaline earth metal elements, rare earth elements, and oxides, hydroxides, nitrides, borides thereof, By mechanically alloying at least one kind of particles selected from sulfides, these particles can be uniformly and finely dispersed in the W-Cu alloy.

  According to this mechanical alloying method, at least one particle selected from alkali metal elements, alkaline earth metal elements, rare earth elements, and oxides, hydroxides, nitrides, borides, and sulfides thereof, The particle size can be reduced to 0.5 μm or less, and if effective mechanical alloying is performed, it can be reduced to about 0.2 μm. Further, the distance between the particles can be set to 5 μm or less, and can be set to 2 μm or less when mechanical alloying is performed effectively. Moreover, according to the mechanical alloying method, it is easy to obtain particularly fine W particles. That is, fine W particles can be formed by heat treatment including mechanical alloying and subsequent sintering. The sintering method may be extrusion or HIP (hot isostatic pressing). As the additive element and additive compound particles become finer and more uniform, the characteristics as an electrode for electric discharge machining become even more favorable.

  Further, at least one kind of particles selected from alkali metal elements, alkaline earth metal elements, rare earth elements, and oxides, hydroxides, nitrides, borides, and sulfides of these elements are included in the W particles. The effect is exhibited more effectively by being present in Cu than there is. For example, Ce, Ba, and the like are preferably dispersed in Cu without being in the state of a complex oxide of these elements and W. In addition, without using the compound powder of these elements and W as a raw material powder, the particle | grains of the additional element or compound can be disperse | distributed in Cu by using these element powder and its compound powder.

  Furthermore, by performing the mechanical alloying method, depending on the processing conditions, alkali metal elements, alkaline earth metal elements, rare earth elements, and oxides, hydroxides, nitrides, borons of these elements. At least one kind of particles selected from a chemical compound and a sulfide can be dispersed in Cu or W particles. Depending on the processing conditions of mechanical alloying, it can be uniformly dispersed in Cu or W particles, but even in a state where it is partially dispersed in a part of the structure in Cu and / or W particles. The characteristics as a processing electrode are improved. Of course, it is not always necessary to form a compound with W or Cu, and it is sufficient that these particles are dispersed.

  Therefore, each electrode material for electric discharge machining of the present invention is selected from alkali metal elements, alkaline earth metal elements, rare earth elements, and oxides, hydroxides, nitrides, borides, and sulfides of these elements. In addition, it is preferable that at least one kind of particles are dispersed in Cu. Regarding dispersion to W particles, it is preferable that at least one kind of particles of these additive elements and additive compounds is contained in at least some W particles, but it is not necessary to be contained in all W particles. . Further, the individual W particles do not need to be dispersed throughout the particle, and improvement in characteristics can be desired as long as the particles partially exist in a part of the particle.

  Among the essential additive elements, alkali metal elements, alkaline earth metal elements, and rare earth elements, the elements that can easily exert the effect of miniaturizing the particle size and the distance between the particles include alkali metal elements such as Na, K, Alkaline earth metal elements include Ca, Sr, Ba, and rare earth elements include Y, Ce, and Nd. However, the present invention is not limited thereto, and an element having a small work function and a small electronegativity is effective in improving the wear resistance and processing speed of the electrode. In particular, Ba, Nd, Ce, Y, Ca, K, and oxides and hydroxides thereof are excellent. In general, an element having a low electronegativity has a higher effect of addition, and an alkaline earth metal element having an atomic weight of Ba or more is particularly effective.

  Further, for at least one kind of particles selected from alkali metal elements, alkaline earth metal elements, rare earth elements, and oxides, hydroxides, nitrides, borides, and sulfides of these elements, By reducing the particle size, the inter-particle distance and the average inter-particle distance, and simultaneously making the W particles fine, local non-uniformity of the W-Cu alloy structure is further reduced, and the wear resistance of the electrode is further improved. be able to. For that purpose, it is preferable to mix | blend W particle | grains with a particle size of 1 micrometer or less so that it may become 30 weight% or more of all the W particle | grains. In order to obtain fine W particles, the mechanical alloying method described above is particularly effective in addition to the method using raw powder of fine W particles. In the case of the alloy system in the present invention, the powder is reduced by hydrogen at a temperature of 500 ° C. or higher to remove moisture and organic solvent, and then mechanical alloying treatment is performed in an Ar atmosphere. The oxygen concentration in the atmosphere is 60 ppm. It is necessary to: Above this, the balance between adhesion and pulverization of powders that should occur during mechanical alloying is poor, and a good microstructure cannot be obtained.

  Some additive elements such as alkaline earth metal elements, alkali metal elements, and rare earth elements have the effect of inhibiting sinterability. In that case, it is desirable to add Ni having an effect of promoting the sintering to the alloy in place of a part of Cu (that is, Ni is not included in the additive element). If the Ni content in the W-Cu alloy exceeds 10% by weight, Ni lowers the electrical conductivity and deteriorates the electrical discharge machining characteristics, which is not preferable.

  In order to produce an electrode material for electric discharge machining comprising the W-Cu alloy of the present invention, alkali metal elements, alkaline earth metal elements, rare earth elements, and oxides, hydroxides, nitrides, borides of these elements At least one powder selected from sulfides and a raw material powder containing Cu powder and / or W powder are mixed as usual, or as a more preferable mixing method, a coprecipitation method or a dry method is used. The mechanical alloying method is used.

  That is, using the raw material powder mixed as described above, an electrode material for electric discharge machining made of a W—Cu alloy can be produced by the following ordinary sintering method or infiltration method. In the case of the sintering method, for example, a W powder containing 30% by weight or more of a powder having an average particle diameter of 1 μm or less and a BaO powder having an average particle diameter of 1 μm as raw materials are mixed with Cu powder to obtain a desired final alloy. The composition. This mixed powder is stamped and then heated and sintered in a hydrogen atmosphere at a temperature equal to or higher than the melting point of Cu.

  Further, in the case of the infiltration method, when mixing the raw material powder, instead of setting it as the final alloy composition, a composition excluding Cu or a composition of, for example, W-2 to 3% by weight Cu, is mixed. Emboss the powder. This embossed body is sintered at the same time as Cu is immersed in the embossed body by means such as immersing in a molten liquid of Cu at a temperature equal to or higher than the melting point of Cu. There is also a method of infiltrating Cu into the sintered body after sintering the embossed body.

[Example 1]
As a raw material powder, W powder having a particle size distribution of 0.5 to 16 μm, Cu powder, and BaO powder having average particle diameters of 1.1 μm and 3.0 μm were used. Mixed for hours. After the obtained mixed powder is embossed, a material obtained by embossing pure Cu powder is brought into contact with this embossed body, heated at 1200 ° C. in a hydrogen atmosphere, and infiltrated with Cu at the same time as sintering. Each W-Cu alloy of Samples 1-3 shown in the following Table 1 of W-30 wt% Cu-0.77 wt% BaO was produced.

  Apart from this, it is the same as the above samples 1 to 3 except that BaO powder having an average particle size of 0.6 μm and 4.0 μm is used and mixed for 15 hours in order to further disperse the powder and shorten the distance between particles. For the BaO powder having an average particle diameter of 0.6 μm, the sample 4 of W-31 wt% Cu-2.4 wt% BaO is used as the final alloy composition of the W—Cu alloy, and the average particle diameter is 4.0 μm. Sample 5 of W-32 wt% Cu-4.15 wt% BaO was prepared for the BaO powder. Further, the final alloy composition was W-30 wt% Cu in the same manner as in Samples 1 to 3 except that the W powder, Cu powder, and BaO powder having an average particle size of 0.9 μm were further mixed with Ni powder. A W-Cu alloy of Sample 6 that was -0.77 wt% BaO-1.2 wt% Ni was prepared.

  Further, as a comparative example, the final alloy composition is the same as W-30 wt% Cu-0.77 wt% BaO under the same conditions as those of Samples 1 to 3 except that BaO powder having an average particle diameter of 4.4 μm was used. A W—Cu alloy of Sample 7 was prepared.

  The cross sections of the W-Cu alloys of Samples 1 to 7 thus prepared were observed with a scanning electron microscope, and the average particle diameter and average interparticle distance of BaO particles and the W particles having a particle diameter of 1 μm or less were observed. The ratio (weight%) in the total W particles was determined, and the obtained results are shown in Table 1 below. Moreover, the electrical discharge machining characteristics were evaluated using the electrodes made of the respective W—Cu alloys of Samples 1 to 7. That is, the electrode is a cathode, and a 15 × 15 mm electrode faces a WC-10-15 wt% Co cemented carbide, which is a workpiece (workpiece), so as to face only a 15 × 5 mm surface. Die-sinking electric discharge machining was performed, and the electrode consumption rate and machining speed at that time were evaluated. The electrode consumption rate was calculated using the processing volume of the workpiece as the denominator and the electrode consumption volume as the numerator. The processing speed indicates the processing volume of the workpiece as a numerical value per minute. The obtained results are also shown in Table 1 below.

  As can be seen from the results shown in Table 1 above, the smaller the average particle size and / or the average interparticle distance of the BaO particles contained in the W-Cu alloy, the better the electric discharge machining characteristics, especially the electrode wear resistance. Are better. On the other hand, it can be seen that Sample 7, which is a comparative example having an average particle diameter of BaO particles larger than 3 μm, is inferior in electric discharge machining characteristics, and in particular, the electrode wear resistance is greatly reduced.

[Example 2]
The same W powder and Cu powder as in Example 1 and Nd ₂ O ₃ powder or CeO ₂ powder with an average particle diameter of 0.6 μm, 1.1 μm, and 4.4 μm were used, and the powder containing these was used as an attritor. For 5 or 15 hours. Thereafter, in the same manner as in Example 1, the final alloy composition of the W—Cu alloy was W-30 wt% Cu—0.7 wt% Nd ₂ O ₃ sample 8 for the Nd ₂ O ₃ powder, W-30. to prepare wt% Cu-2.1 wt% _Nd 2 _{O 3} in sample 9, and W-30 wt% Cu-0.7 wt% _Nd sample 10 of 2 _{O 3,} also W-30 for the CeO ₂ powder wt% Cu-0.67 wt% CeO ₂ of the sample 11, W-30 wt% Cu-2.0 wt% CeO ₂ of the sample 12 and W-30 wt% Cu-0.7 wt% CeO ₂ samples, 13 was produced.

For each W-Cu alloy of the obtained sample 8-13, and its cross section was observed by a scanning electron microscope, the average particle diameter and the average distance between particles of _Nd 2 _{O 3} or the particles of CeO _2, and particle size 1μm The ratio (% by weight) of the following W particles to the total W particles was determined, and the results are shown in Table 2 below. Moreover, using the electrode which consists of each W-Cu alloy of sample 8-13, the electrical discharge machining characteristic was evaluated like Example 1, and the result was combined with Table 2 and shown.

From the results shown in Table 2 above, even when the oxide contained in the W—Cu alloy is Nd ₂ O ₃ or CeO ₂ , the smaller the average particle size and / or the average interparticle distance, the better the electrical discharge machining characteristics. It turns out that it is excellent. On the other hand, in the samples 10 and 13 of the comparative examples in which the average particle diameter of the oxide particles is larger than 3 μm, it can be seen that the wear resistance of the electrode is significantly lowered.

[Example 3]
By the same method as in Example 1, the final composition is W-30 wt% Cu-0.77 wt% BaO, and BaO particles having a particle size of 3 μm or less (sample 17 is 1 μm or less) account for the entire alloy. Samples 14 to 18 having ratios shown in Table 3 below were prepared. Further, Sr was used instead of Ba, and similarly, a sample 19 having a final composition of W-30 wt% Cu-0.77 wt% was also produced. About the W-Cu alloy of each obtained sample, in the same manner as in Example 1, the proportion (% by weight) of BaO particles or SrO particles having a particle size of 3 μm or less (sample 17 of 1 μm or less) in the total alloy The ratio (weight%) of W particles having a particle size of 1 μm or less to the total W particles was determined, the electrode consumption rate and the processing speed were evaluated, and the results are shown in Table 3 below.

  As can be seen from the results of Table 3 above, the larger the ratio (% by weight) of the particles having a particle size of 3 μm or less among the BaO particles and SrO particles contained in the W—Cu alloy, the better the electric discharge machining characteristics. Yes. It was confirmed that BaO particles and SrO particles were dispersed in Cu for all the W-Cu alloys of the samples prepared.

[Example 4]
According to the same method as in Example 1, the final composition is W-30 wt% Cu-0.77 wt% BaO, and the proportion of BaO particles with an interparticle distance of 20 μm or less and 10 μm or less in the entire alloy (wt%). Samples 20 to 23 shown in Table 4 below were produced. Sample 22 is a powder produced by a mechanical alloying method. That is, the sample 22 was mixed with an attritor in the same manner as in Example 1, and then the powder was reduced to remove moisture and organic solvent. The oxygen concentration was 56 ppm or less in an Ar atmosphere again with the attritor apparatus. In this state, a mechanical alloying process was performed for 60 hours at a rotational speed of the agitator of 200 rpm. Other than that, it was set as the same process conditions as another sample. About the obtained W-Cu alloy of each sample, it carried out similarly to Example 1, the ratio (weight%) to the whole alloy of the BaO particle | grains whose particle distance is 20 micrometers or less and 10 micrometers or less, and W with a particle size of 1 micrometer or less. While calculating | requiring the ratio (weight%) which occupies for all the W particles of a particle | grain, the electrode consumption rate and the processing speed were evaluated, and the result was shown in following Table 4.

  As can be seen from the results in Table 4 above, regarding the BaO particles contained in the W—Cu alloy, the larger the proportion (wt%) of the particles having an interparticle distance of 20 μm or less, the more the proportion of particles of 10 μm or less ( The larger the weight%), the better the electric discharge machining characteristics. In addition, it was confirmed that BaO particles were dispersed in Cu for all the W-Cu alloys of the samples prepared.

Claims (17)

A W-Cu alloy comprising 40 wt% or more of W, 15 wt% or less of an additive element or compound thereof, and the balance of Cu, and the additive element or compound thereof includes an alkali metal element and an alkaline earth metal element And 10% by weight or less of at least one selected from rare earth elements and oxides, hydroxides, nitrides, borides and sulfides of these elements, and the average particle size of the particles is less than 3 μm An electrode material for electric discharge machining characterized by A W-Cu alloy comprising 40 wt% or more of W, 15 wt% or less of an additive element or compound thereof, and the balance of Cu, and the additive element or compound thereof includes an alkali metal element and an alkaline earth metal element , Rare earth elements, and at least one selected from oxides, hydroxides, nitrides, borides, and sulfides of these elements in an amount of 10 wt% or less, and the average interparticle distance of the particles is 20 μm or less. An electrode material for electric discharge machining characterized by the above. A W-Cu alloy comprising 40 wt% or more of W, 15 wt% or less of an additive element or compound thereof, and the balance of Cu, and the additive element or compound thereof includes an alkali metal element and an alkaline earth metal element , Rare earth elements, and at least one selected from oxides, hydroxides, nitrides, borides, and sulfides of these elements, and the average particle diameter of the particles is less than 3 μm, and An electrode material for electric discharge machining having an average interparticle distance of 20 μm or less. The at least one kind of particles selected from the alkali metal elements, alkaline earth metal elements, rare earth elements, and oxides, hydroxides, nitrides, borides and sulfides of these elements have an average particle diameter. The electrode material for electric discharge machining according to claim 1, wherein the electrode material is less than 1 μm. The at least one kind of particles selected from the alkali metal elements, alkaline earth metal elements, rare earth elements, and oxides, hydroxides, nitrides, borides, and sulfides of these elements have an average interparticle distance. The electrode material for electric discharge machining according to any one of claims 1 to 4, wherein the electrode material is 10 µm or less. A W-Cu alloy comprising 40 wt% or more of W, 15 wt% or less of an additive element or compound thereof, and the balance of Cu, and the additive element or compound thereof includes an alkali metal element and an alkaline earth metal element , Rare earth elements, and at least one selected from oxides, hydroxides, nitrides, borides, and sulfides of these elements containing 10 wt% or less, and particles having a particle size of 3 μm or less are included in the entire alloy. An electrode material for electric discharge machining comprising 0.3% by weight or more. At least one selected from the alkali metal elements, alkaline earth metal elements, rare earth elements, and oxides, hydroxides, nitrides, borides, and sulfides of these elements, and the particle size thereof is 3 μm. The electrode material for electric discharge machining according to claim 6, wherein the following particles are contained in an amount of 0.6% by weight or more based on the whole alloy. At least one selected from the alkali metal elements, alkaline earth metal elements, rare earth elements, and oxides, hydroxides, nitrides, borides, and sulfides of these elements, each having a particle size of 1 μm The electrode material for electric discharge machining according to claim 6 or 7, wherein the following particles are contained in an amount of 0.3 wt% or more of the whole alloy. A W-Cu alloy comprising 40 wt% or more of W, 15 wt% or less of an additive element or compound thereof, and the balance of Cu, and the additive element or compound thereof includes an alkali metal element and an alkaline earth metal element Alloys particles containing 10% by weight or less of a rare earth element and at least one selected from oxides, hydroxides, nitrides, borides, and sulfides of these elements and having an interparticle distance of 20 μm or less An electrode material for electric discharge machining comprising 0.3% by weight or more of the whole. The alkali metal element, alkaline earth metal element, rare earth element, and at least one selected from oxides, hydroxides, nitrides, borides, and sulfides of these elements, and the interparticle distance is The electrode material for electric discharge machining according to claim 9, comprising particles having a particle size of 10 μm or less of 0.3% by weight or more of the whole alloy. The alkali metal element, alkaline earth metal element, rare earth element, and at least one selected from oxides, hydroxides, nitrides, borides, and sulfides of these elements, and the interparticle distance is 11. The electrode material for electric discharge machining according to claim 9, wherein particles containing 10 μm or less are contained in an amount of 0.7% by weight or more based on the whole alloy. At least one particle selected from the alkali metal elements, alkaline earth metal elements, rare earth elements, and oxides, hydroxides, nitrides, borides, and sulfides of these elements is present in Cu. The electrode material for electric discharge machining according to claim 1, wherein the electrode material is an electric discharge machining electrode material. At least one kind of particles selected from the alkali metal elements, alkaline earth metal elements, rare earth elements, and oxides, hydroxides, nitrides, borides, and sulfides of these elements are part of the W particles. Electrode material for electric discharge machining according to any one of claims 1 to 12, characterized in that it exists. The alkali metal element, alkaline earth metal element, rare earth element, and oxides, hydroxides, nitrides, borides, and sulfides of these elements are Ba, Nd, Ce, Y, Ca, K, or the like The electrode material for electric discharge machining according to any one of claims 1 to 13, wherein the electrode material is at least one of an oxide and a hydroxide. The electrode material for electric discharge machining according to any one of claims 1 to 14, wherein the W has a particle size of 1 µm or less of 30 wt% or more of all W particles. The electrode material for electric discharge machining according to any one of claims 1 to 15, further comprising 10 wt% or less of Ni instead of a part of the Cu. It is a manufacturing method of the electrode material for electrical discharge machining in any one of Claims 1-16, Comprising: An alkali metal element, an alkaline-earth metal element, a rare earth element, and the oxide, hydroxide, nitride of these elements A raw material powder containing at least one powder selected from boride and sulfide, Cu powder and / or W powder, mechanical alloying method, method using fine raw material powder, coprecipitation method A method for producing an electrode for electric discharge machining, comprising using raw material powder mixed by any of the methods used.