JPS61249275A - Manufacture of abrasive grain - Google Patents

Abstract

PURPOSE:To improve specific conductance, hardness and thermal conductivity in an abrasive grain so better, by cladding a surface of each grain serving as a ground with ametal by means of electrodeposition process by evaporation, and nitrifying or carbonizing this metal. CONSTITUTION:Titanium is clad on a surface of a SiC grain 1 or a ground by means of evaporation or the like whereby a TiC covering layer 2 is formed there. Specific conductance, hardness and thermal conductivity in this abrasive grain secured by the presence of this covering layer 2 is able to be more excellent than those of a SiC single grain. In addition, graindability in this grain can be made yet higher, while manufacturing cost in this grain is reducible, and the ground grain and the quality of material in this covering layer are properly selected, so that specific conductance, hardness, thermal conductivity and so on in the abrasive grain are optionally selectable.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention mainly relates to a method for producing abrasive grains suitable for use as a grindstone for grinding processes such as electrolytic grinding.

(Prior art) Grinding wheels used for grinding are made of diamond, poor conductors such as A203.5i02, SiC, Ti, etc.
B2. Constructed by using semiconductors such as B4C, Tic, TiN, WC, etc. as abrasive grains and bonding them with frit, vitrified, silicate, other porcelain binders, resin, rubber, carbon, metal, etc. be done.

(Problems to be solved by the invention) With conventional abrasive grains, depending on the type of material, such as TiC, it may be difficult to obtain a desired grain size, and it may be difficult to obtain an optimal grain size. . In addition, the electrical conductivity, hardness, thermal conductivity, etc. are uniquely determined by the type of material.
It was difficult to obtain one with arbitrary characteristics.

(Means for Solving the Problems) The method for producing abrasive grains of the present invention includes coating the surface of a defective conductor or semiconductor particle with a metal by a thin film forming method such as vapor deposition, sputtering, ion blasting, or CVD method. By carbonizing or nitriding the metal, a single or multilayer carbide or nitride coating layer having high electrical conductivity or thermal conductivity, high hardness, and high wear resistance is formed. By using materials with high thermal conductivity and high hardness.

When formed as a grinding wheel for electrolytic grinding etc. In addition, by selecting the material that forms the coating layer, the internal particles can be strengthened, and furthermore, materials such as TiC and TiN, which are difficult to obtain only in relatively small diameters, can be improved. For this, SiC is used as the underlying particle.
Use something that is easy to obtain with a relatively arbitrary diameter, such as
By using TiC or TiN for the target 71, TIC
It is possible to obtain abrasive grains having strong characteristics of TiN or TiN.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a cross section of particles when the present invention is implemented, and S
A TiC coating layer 2 is formed by coating the surface of particles 1 made of iC with Ti by vapor deposition or the like and carbonizing the Ti.

Specifically, particles l with a particle diameter of about 40 to loOILm
The surface of the particles is coated with Ti to an average thickness of about 10 pm by sputtering, and then carbon powder having a particle size of about a fraction of the particle size of 1 particle is mixed with the obtained particles and heated. By carrying out the carbonization reaction for 1.5 hours, T
An iC coating layer 2 was formed.

The thus obtained coated particle powder is mixed with frit at a mixing ratio of 15% by weight, pressure molded, and sintered at 1300°C to obtain a grindstone. In this case, the porosity is 32% and the tensile strength is 42 Kg/
cs+" was able to be obtained. Also, the specific resistance value was 0.4ΩC layer. On the other hand, using the same material, Ti
When the C coating was not applied, a specific resistance value of 1Ωc+s was obtained when the mixing ratio of frits was kept the same. In addition, at an electrolytic voltage of 4 V and a current density of 5 A/c + s2, 6% C
When machining WC material containing O, the machining speed is 1 or 2.
g/sin. On the other hand, under the same conditions, in the case without the TiC coating layer 2, the processing speed was 0.7 g/in.

In this way, by coating TiC, the electrical conductivity is increased to S
It is possible to obtain particles with higher hardness and comparable hardness than when using IC alone. In addition, TiC alone can only yield particles with a relatively small diameter, but by using TiC as a coating layer, TiC-coated particles with a particle size that can be obtained as SiC particles, that is, particles with properties close to those of TiC, can be obtained. It will be done. Furthermore, since there is a correspondence between electrical conductivity and thermal conductivity, if one is high, the other is also high, so it is possible to obtain a grindstone with higher thermal conductivity than when using SiC alone.

In FIG. 1, TiN can also be formed instead of TiC. In this case, after forming the Ti coating layer as described above, it can be nitrided by heating by glow discharge in an N, gas, or NH3 gas atmosphere. *TiN has a specific resistance compared to TIC. Since the value is even smaller, it is advantageous for electrolytic grinding.

FIGS. 2 and 3 show cross sections of particles obtained according to other examples of the present invention. In all of these examples, the TEN layer 3 is formed in addition to the Ti0 layer 2 in multiple layers using the method explained in connection with FIG. 1. In the example shown in FIG. In the example shown in FIG. 3, the TEN layer 3 is the lower layer and the Ti0 layer 2 is the surface layer.

As shown in FIGS. 2 and 3, if the m-layer is formed into multiple layers, particles with intermediate characteristics can be obtained by combining these layers,
By changing the ratio, the characteristics can be varied in various ways.

Of course, in addition to these, for example, TiC or TiN particles may have S
Those coated with an iC layer, and the diamond A4120g described in the prior art section.

Bad conductor such as S i 02, or T i B2,
Metal carbide or nitride can also be formed as a coating layer on other semiconductor particles such as B4C. Also,
The particles that serve as the base material are not of one type, but are a mixture of multiple types, or the particles that serve as the base material include Y, Sm,
An alloy of rare earth elements such as La and Ce can also be used.

In addition, when the abrasive grains obtained according to the present invention are used as a grinding wheel, in addition to conventional porcelain materials and metal-based binders, resins such as epoxy resins and phenol resins, or rubber may be used as the bonding material. Alternatively, a grindstone can be obtained by mixing the abrasive grains with a coating layer formed as described above and other abrasive grains with or without a coating layer together with a binder.

(Effects of the Invention) As described above, the method for producing abrasive grains according to the present invention coats the surface of the underlying particles with a metal by vapor deposition or the like, and carbonizes or nitrides the metal, thereby increasing the electrical conductivity or Since this is a method of obtaining a single or multilayer carbide or nitride coating layer with high thermal conductivity and high hardness, a material that can be obtained with various particle sizes is selected as the base material, and the coating layer is made of grains. By depositing particles whose diameter is difficult to select, the optimum particle size can be easily obtained even for materials whose arbitrary particle size is difficult to select.

Furthermore, by using an expensive substance such as Ti for the coating layer, the overall cost of the abrasive grain can be reduced. Further, by selecting the materials of the base material and the covering layer, electrical conductivity, hardness, thermal conductivity, etc. can be arbitrarily obtained.

[Brief explanation of the drawing]

1 to 3 are cross-sectional views showing examples of abrasive grains obtained by the method of the present invention.

Claims (1)

[Claims] It is characterized by coating the surface of a defective conductor or semiconductor particle with a metal and carbonizing or nitriding the metal to form a single or multilayer carbide or nitride coating layer with high conductivity and high hardness. A method for producing abrasive grains.