JP2013095935A - Electrode for electrical discharge surface treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode for electrical discharge surface treatment which achieves an efficient movement of an electrode component material to a material to be treated.SOLUTION: The electrode for electrical discharge surface treatment 10 forms a coating including at least a part of the electrode component material on the surface of the material to be treated by discharging between itself and the material to be treated. The electrode can achieve stable discharging with less deviation in which conductive diamond particles 12 dispersed in the electrode become a starting point for discharging during discharge treatment, and can transmit the heat generated by discharging to material particles 14 efficiently due to the high thermal conductivity. Thereby, the electrode for electrical discharge surface treatment 10 can achieve efficient movement of the material particles 14 to the material to be treated 18, and suppress the generation of electrode scraps while increasing an amount of the coating to be formed on the material to be treated 18 per an electrode consumption rate.

Description

  The present invention relates to an electrode for discharge surface treatment used for discharge surface treatment.

  Electrical discharge machining and electrical discharge surface treatment have been developed as techniques for generating electrical discharge between a material to be processed and an electrode installed in an oil liquid and using the energy of the electrical discharge. Whereas the electrode used for electric discharge machining is sufficient to realize electric discharge machining, the electrode used for electric discharge surface treatment is an electrode having a void inside that is compression-molded with a material that is the basis of the coating. Therefore, properties and functions different from those of electrodes used for electric discharge machining are required. That is, at least a part of the constituent material of the discharge surface treatment electrode needs to move to the surface of the material to be treated by the discharge energy, and the constituent material, strength (easiness to collapse), electrical conductivity, etc. It is very different from the electrode for the use.

  As a conventional technique related to such an electrode for discharge surface treatment, for example, an electrode using a green compact obtained by press-molding a metal powder or a metal compound powder is disclosed (see Patent Document 1, etc.). However, it is difficult for the conventional electrode for discharge surface treatment to ensure the uniformity of the bonding force of the powder contained therein, and the discharge energy of the discharge surface treatment may concentrate on a specific part. As a result, the discharge surface electrode according to the prior art may cause a phenomenon in which a specific portion is excessively collapsed. As a result, a problem arises in that the rate at which the film is formed decreases. Among the collapsed constituent materials of the electrode, those that do not move to the material to be processed float in the oil as electrode scraps.

  On the other hand, as a conventional technique related to an electrode for electric discharge machining instead of an electrode for electric discharge surface treatment, a technique is disclosed in which fine polycrystalline diamond is dispersed in the electrode in order to reduce electrode consumption (see Patent Document 2, etc.). ). However, the technology related to the electrode for electric discharge machining is for solving the problem of reduction of electrode consumption, and is effective for the problem of realizing the efficient transfer of the electrode constituent material to the material to be processed. There is no mention of whether or not there is. In addition, since the mechanical and electrical properties of the electric discharge machining electrode and the electric discharge surface treatment electrode are greatly different as described above, it is difficult to apply one technique to the other.

International Publication No. 99/46423 JP 2006-167893 A

  This invention is made | formed in view of such a subject, The objective is to provide the electrode for discharge surface treatment which implement | achieves the efficient movement to the to-be-processed material of an electrode constituent material.

In order to solve the above-described problems, an electrode for discharge surface treatment according to the present invention is:
A discharge surface treatment electrode for forming a film including at least a part of an electrode constituent material on a surface of the material to be treated by discharge between the material to be treated,
Contains conductive diamond particles.

  Unlike insulative diamond, conductive diamond is suitable for discharge surface treatment without impairing the conductivity of the electrode, even within the discharge surface treatment electrode having voids inside and having a relatively fragile property. Can be the starting point. Therefore, the discharge surface treatment electrode in which the conductive diamond is dispersed inside can realize a stable discharge with little unevenness in the discharge portion. In addition, since the discharge surface treatment electrode has a void inside, has a small heat transfer area, and has a structure in which heat is likely to accumulate, the use of diamond having high thermal conductivity for this electrode effectively Heat generated by the discharge can be transmitted to the surrounding electrode constituent materials. Thereby, the electrode for electrical discharge surface treatment which concerns on this invention can implement | achieve the efficient movement to the to-be-processed material of an electrode constituent substance, and can suppress generation | occurrence | production of an electrode scrap.

Further, for example, the discharge surface treatment electrode according to the present invention further includes material particles to be moved to the material to be treated,
The conductive diamond particles may be diamond to which impurities are added, and the conductive diamond particles may be dispersed in the material particles.

  There are several types of conductive diamond particles, one of which is diamond to which impurities such as boron are added. The discharge surface treatment electrode including this type of conductive diamond particles includes material particles that move to the material to be processed in addition to the conductive diamond particles. Conductive diamond particles become the starting point of discharge during electrode surface treatment, and realize stable discharge. Such a discharge surface treatment electrode has voids inside, has a small heat transfer area, and heat is Even if the structure tends to accumulate, the heat generated by the discharge can be efficiently transmitted to the surrounding electrode constituent materials by using diamond having high thermal conductivity for this electrode.

  For example, the conductive diamond particles may include diamond and a conductive material coated on the surface of the diamond.

  As another example of the conductive diamond particles, a surface of normal diamond having no conductivity and a conductive material coated thereon may be mentioned. Such conductive diamond particles also serve as the starting point of discharge during electrode surface treatment, and can realize stable discharge. In addition, the electrode for discharge surface treatment using such conductive diamond particles can also be used as a coating material by moving the conductive material coated with diamond to the material to be treated during the discharge surface treatment. It is.

FIG. 1 is a conceptual diagram showing an outline of surface treatment using a discharge surface treatment electrode according to an embodiment of the present invention. FIG. 2 is a conceptual diagram showing the fine structure of the discharge surface treatment electrode.

The discharge surface treatment electrode according to an embodiment of the present invention will be described below with reference to the drawings and the like.
FIG. 1 is a conceptual diagram showing an outline of discharge surface treatment using a discharge surface treatment electrode 10 according to an embodiment of the present invention. In the discharge surface treatment, a discharge is generated between the material to be treated 18 installed in the machining liquid 16 and the discharge surface treatment electrode 10, and the hard film 20 is formed on the surface of the material to be treated 18 by the energy. The coating film 20 formed in the discharge surface treatment is formed using the electrode constituent material of the discharge surface treatment electrode 10 that is melted or the like during discharge.

  FIG. 2 is a conceptual diagram showing the microstructure of the discharge surface treatment electrode 10 shown in FIG. As shown in FIG. 2, the discharge surface treatment electrode 10 includes material particles 14 and conductive diamond particles 12 dispersed in the material particles 14. The content ratio of the conductive diamond particles 12 in the discharge surface treatment electrode 10 is not particularly limited, and is adjusted according to the material of the material particles 14 and the properties of the coating 20 formed on the surface of the material 18 to be treated by the discharge treatment. However, it can be in the range of 5% to 95%, for example.

  As shown in FIG. 2, the material particles 14 and the conductive diamond particles 12 may be directly bonded by pressure molding or the like, but between these particles, other metal powders that mediate the bonding of the particles, Resin or carbon may be present. Moreover, as long as an electrode has moderate intensity | strength, the space | gap inside an electrode may be what kind of shape.

At least a part of the material particles 14 is moved to the surface of the material 18 to be processed by the discharge surface treatment, and becomes a material constituting the coating 20 on the surface of the material 18 to be processed. The material of the material particles 14 is selected according to the coating 20 formed on the surface of the material to be treated 18 by the discharge surface treatment of the discharge surface treatment electrode 10, and is not particularly limited, and examples thereof include metals and metal compounds. Specifically, titanium (Ti), titanium hydride (TiH ₂ ), titanium carbide (TiC), titanium nickel alloy (TiN), tungsten carbide, chromium carbide, cobalt, BN, B4C, boride, MoSi ₂ , oxidation Examples thereof include iron and zinc oxide. Note that the properties of the coating film 20 formed on the surface of the material to be processed 18 are affected not only by the material particles 14 themselves, but also by the discharge conditions, the substance in which the constituent material of the electrode 10 reacts with the discharge energy, and the material of the material 18 to be processed. I can receive it.

  The conductive diamond particles 12 are diamond particles imparted with conductivity, and there are diamonds to which at least impurities are added and those obtained by coating the surface of diamond with a conductive material. Examples of the diamond to which impurities are added include diamond doped with boron, phosphorus, nitrogen, or the like, and is manufactured by a high-temperature high-pressure method or a microwave plasma CVD method. Normal diamond containing no impurities is an insulator. For example, diamond doped with boron has conductivity depending on the amount of boron added.

  The type of conductive diamond particles 12 in which the surface of diamond is coated with a conductive material is obtained by coating the surface of diamond with a conductive material such as a metal element. The coating method and the conductive material used for coating are not particularly limited as long as the particle surface after coating is treated so as to be a conductive path.

An example of a method for producing the discharge surface treatment electrode 10 shown in FIGS. 1 and 2 is shown below.
In the method for manufacturing the discharge surface treatment electrode 10, first, material particles 14 and conductive diamond particles 12 as raw materials are prepared. The material particles 14 may be a powder produced by pulverization with a ball mill or the like, or an aggregate in which the powder is agglomerated. Although the particle diameter of the material particle 14 is not specifically limited, For example, it can be set as about 1-100 micrometers. The manufacturing method of the conductive diamond particles 12 is as described above, and the particle diameter is not particularly limited, but can be set to about 0.1 to 100 μm, for example.

  Next, the material particles 14 and the conductive diamond particles 12 are mixed to produce a mixed powder of the electrode material. At this time, for example, a soft metal or the like may be added as a binder depending on the binding force of the material particles 14. Further, the mixed powder is pressure-molded and then sintered to obtain the discharge surface treatment electrode 10.

  In the discharge surface treatment electrode 10 including the conductive diamond particles 12 as shown in FIG. 2, the conductive diamond particles 12 dispersed in the electrode become the starting point of discharge during the discharge treatment, and the discharge is stable with little bias. In addition, due to its high thermal conductivity, the heat generated by the discharge can be efficiently transferred to the material particles 14. As a result, the discharge surface treatment electrode 10 realizes efficient movement of the material particles 14 to the material 18 to be treated, and the amount of film formation on the material 18 to be treated with respect to the unit electrode consumption amount increases, and the electrode scraps Can be suppressed.

  Here, the conductive diamond particles 12 included in the discharge surface treatment electrode 10 have such a remarkable effect because they are not insulating but conductive. In general, an electrode for electric discharge surface treatment is different from an electrode for electric discharge machining, and a part of the electrode moves to the surface of the material to be processed 18 and a new coating 20 is applied to the surface of the material to be processed 18. Therefore, it is not dense as compared with the electrode for electric discharge machining, has a gap inside, and a material for moving to the material to be processed 18 is selected as the electrode material, so that the material having a relatively low electric conductivity is used. May be selected, and an electrode having low electrical conductivity may be produced. In such an electrode for surface treatment of electric discharge, even if it contains ordinary diamond that is insulating like the electrode for electric discharge machining, due to problems such as insufficient formation of a conductive path in the part, It is difficult to be a starting point for stable discharge.

  However, the discharge surface treatment electrode 10 including the conductive diamond particles 12 can serve as a starting point of discharge in the discharge surface treatment because the conductive diamond particles 12 have conductivity. In addition, since the discharge surface treatment electrode moves the constituent material to the material to be treated, the constituent material is destroyed by the discharge. However, in the conventional discharge treatment electrode, the electrode constituent material is destroyed by being discharged from a specific portion. In this case, the starting point of the next discharge may occur randomly. However, in the discharge surface treatment electrode 10 according to the present embodiment, since conductive diamond particles are present, conductive diamond close to the material to be treated 18 becomes a starting point of discharge, and stable discharge can be performed.

  When the conductive diamond particles 12 coated with a conductive material are used, the discharge surface treatment electrode is coated with the coated conductive material even without the material particles 14 as shown in FIG. It can be moved to the treatment material 18 and used as the material of the coating 20, and the discharge surface treatment can be performed.

DESCRIPTION OF SYMBOLS 10 ... Electrode for discharge surface treatment 12 ... Conductive diamond particle 14 ... Material particle 16 ... Processing liquid 18 ... Material to be processed 20 ... Film

Claims (3)

A discharge surface treatment electrode for forming a film including at least a part of an electrode constituent material on a surface of the material to be treated by discharge between the material to be treated,
An electrode for discharge surface treatment, comprising conductive diamond particles. Further comprising material particles to be transferred to the material to be treated;
2. The discharge surface treatment electrode according to claim 1, wherein the conductive diamond particles are diamond to which impurities are added, and the conductive diamond particles are dispersed in the material particles.   2. The discharge surface treatment electrode according to claim 1, wherein the conductive diamond particles include diamond and a conductive material coated on a surface of the diamond.

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