JPH0356868B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for joining abrasive molded bodies.

Abrasive compacts are well known in the art and are widely used in industry for polishing a variety of workpieces. These consist essentially of agglomerates of abrasive particles present in an amount of at least 70% by volume, preferably from 80% to 90% by volume of the volume of the compact, bonded into a solid agglomerate. There is. The compact is a polycrystalline nodule with some direct diamond-to-diamond bonding. The abrasive particles of the compact are necessarily ultra-hard abrasives such as diamond and cubic boron nitride.

The abrasive compact may contain a second phase, a binding matrix that contains a catalyst (also known as a solvent) that is effective in synthesizing the particles. In the case of cubic boron nitride, examples of suitable catalysts are aluminum or alloys of aluminum with nickel, cobalt, iron, manganese or chromium. In the case of diamond, examples of suitable catalysts are metals from group 8 of the periodic table, such as cobalt, nickel or iron, or alloys containing such metals.

The abrasive compact can be provided in the form of a disk or a section thereof, or other shaped pieces.

Diamond and cubic boron nitride compacts are produced under conditions of temperature and pressure in which the abrasive particles are crystallographically stable.

The abrasive compact can be bonded directly to the tool used or to the handle of the tool. Alternatively, it can be bonded to a backing, such as a cemented carbide backing, before being secured to the tool or tool handle. Abrasive compacts bonded to a backing, typically a sintered carbide backing, are also referred to as "composite abrasive compacts".
It is also known as "compacts".

Examples of abrasive compacts and composite abrasive compacts can be found in numerous patent specifications, such as British Patent Nos. 1489130, 1456765, and 2048927, and U.S. Patent No. 3745623. Specification, No.
No. 3743489 and No. 4224380.

According to the present invention, nickel, copper, cobalt,
A layer of iron, or an alloy containing one or more of these metals, is inserted between the surface of the compact and the surface of the holder, and the compact is heated at a temperature lower than the melting point of the layer. A method of bonding an abrasive compact to a metal-containing carrier includes the step of diffusion bonding to the carrier through an intercalating layer.

FIG. 1 shows a side cross-sectional view of the combined product used in the method of the invention, and FIG. 2 shows a perspective view of a part of the combined product of FIG. 1 in cross section.

The method of the present invention uses diffusion bonding techniques. Diffusion bonding is known in the art and is a method of creating a metal-to-metal bond in which atoms of the metal migrate past the bond interface and create a continuous structure.
This method is a method in which the metal is not allowed to reach its melting point, but in a solid state. Diffusion bonding has been found to produce excellent strength bonds between the compact and the carrier under conditions that do not substantially damage the abrasive particles of the abrasive compact. In other words, in the case of a diamond compact, the compact is substantially free of graphite, and in the case of a cubic boron nitride compact, it is substantially free of hexagonal boron nitride.

The method of the present invention comprises: (a) providing a layer of nickel, copper, cobalt, iron, or an alloy containing one or more of these metals on the surface of the holder; (b) the metal layer (c) pressing the compact and the holder together by applying pressure transversely thereto; (d) pressing the compact and the holder together so that they are in contact with the surface of the compact; and (d) removing the metal layer. (e) maintaining the pressure and temperature for a period sufficient to effect diffusion bonding between the compact and the carrier; (d) and (e) are carried out in an inert atmosphere. Here, the abrasive compact is a cubic boron nitride compact or a diamond compact, and the holder is sintered tantalum carbide, sintered tungsten carbide, sintered titanium carbide, or a mixture thereof.

While diffusion bonding the backing to the substrate, the pressure applied is generally between 40N/ ^mm2 and 300N/ ^mm2 ;
The temperature used is typically between 650°C and 950°C. In the case of diamond bodies with a second phase containing a diamond catalyst, the temperature is generally not higher than 750°C. Diffusion bonding
Damage to the abrasive particles of the abrasive compact is minimized if done in a vacuum of 10 ^-4 Torr or better, or other inert atmosphere such as an inert gas. The pressure and temperature can be maintained for a period of 5 minutes to 360 minutes, typically 5 minutes to 35 minutes to ensure a good bond.

In the method of the invention, by methods known in the art, e.g. using a hydraulic cylinder-compressor,
Transverse pressure can be applied.

A unique method of applying the desired cross-sectional pressure to the compact and retainer takes advantage of the difference in coefficient of thermal expansion between the outer envelope and the inner expanding body. In this method, after bonding the molded body and the holding body in step (c), an envelope is formed which has a cavity therein, and the thermal expansion coefficient inside the cavity is higher than that of the envelope. into the cavity of the combined article consisting of a large expanded body, and the temperature of the combined article is raised to the desired temperature in step (d) to expand the expanded body, and the molded body and the holding body are subjected to step (d). c) applying the desired cross-sectional pressure.

Typically, the temperature of the combined product is raised by placing the combined product in a furnace.

The enclosure may be made of sintered carbide or ceramic based on silicon nitride or zirconia.

The expansion body is typically made of metal or alloy with a large coefficient of thermal expansion. An example of a suitable alloy is the nickel-based alloy Nimonic.

The surface of the cavity in contact with the inflation body may be sloped and may be commensurate with the sloped surface of the inflation body. Alternatively, the expansion body may be in contact at two points, and the contact surfaces may be sloped and balanced.

If the expansion body reacts adversely with the components to be joined under the temperature conditions used, a suitable inert filler can be placed between the components to be joined and the expansion body.

This pressing method is particularly used for joining the abrasive compact to the tool handle, ie the tool handle is the retainer.

1 and 2 illustrate embodiments of this aspect of the invention.

With reference to these drawings, a composite article 20 is shown consisting of an enclosure 22 made of cemented carbide and having a groove or cavity 24 formed therein. The enclosure 22 is secured in a recess 26 in a steel retaining base 28.

Within cavity 244 are oppositely facing wedges 30, 32 with inclined surfaces touching along line 34. This Susabi is made of Alloy Nimonic.

There is also a filling element 36 in the cavity and a wedge 32
is placed in contact with surface 38 of. Between the filling element 36 and the surface 40 of the enclosure there is a handle 4 of the tool with which the abrasive compact 44 is to be joined.
2 is placed. Between the tool handle 42 and the compact 42 there is placed a thin metal layer 46 suitable for diffusion bonding between the tool handle and the compact. In order to effect an advantageous diffusion bond between the tool handle and the compact, the entire assembly is placed in an oven at a suitable temperature. The temperature must be such that diffusion bonding occurs. At this temperature, Nimonik Susabi is 30.3
2 expands at a faster rate than the envelope 22. This has the effect of applying bonding pressure to the handle 42 of the tool and the molded body 44.

It is important and preferred to polish the exposed surface of the metal layer to ensure that the surface is as flat as possible. Polishing can be done using a diamond abrasive tool. The surface of the molded body to which the holder is joined should also be kept as flat as possible.

The metal layer that is bonded to the surface of the holder is particularly prone to bending and twisting during polishing. To minimize this, a layer can be deposited on the surface,
Preferably, a cross-sectional pressure is applied to the layer, the temperature of the layer is raised to a temperature below the melting point, and the pressure and temperature are maintained for a sufficient time to allow the layer to bond to the substrate. I found out. The pressure applied to the layer typically ranges from 1 N/mm ² to 200 N/mm ² and the temperature at which the metal layer is heated is typically from 700°C to 1100°C. These conditions of temperature and pressure can be maintained for a period of from 5 minutes to 300 minutes, typically from 5 minutes to 30 minutes. In the art, such as electroplating, electroless plating, vapor deposition or sputtering, or placing a metal foil in contact with a carrier, or placing a foil in contact with a metal-coated surface of a carrier, etc. Then, metal can be deposited on the surface of the substrate by a known method. Applying cross-sectional pressure can be accomplished by methods known in the art.

Before bringing the molded body into contact with the metal-coated surface of the holder, coat the surface of the molded body to be joined with the same or similar metal used to coat the surface of the holder. A thin metal coating may also be applied. Such layers can be deposited on the surface of the shaped body of such layers by methods known in the art such as electroplating, electroless plating, vacuum deposition and sputtering.

Abrasive compacts can be any known in the art, as discussed in detail above. For details,
The abrasive compact may be a diamond compact or a cubic boron nitride compact.

The holder may be a tool handle, or it may be such that it forms a composite abrasive compact with the abrasive compact.

Holders for composite abrasive compacts may be made of sintered carbide, as is known in the art. Examples of suitable cemented carbides are cemented titanium carbide, cemented tantalum carbide, cemented tungsten carbide, or mixtures thereof. The metallic phase for cemented carbides is generally nickel, cobalt, or iron present in an amount from 3% to 35% by weight.

The holder generally has a mass and volume greater than the mass and volume of the abrasive compact.

The thickness of the bonding layer between the molded body and the holding body is generally
Less than 220μ. By means of the method of the invention it is possible to achieve a shear strength of the joint between molded body and holding body of at least 100 N/mm ² .

The following examples further illustrate the invention.

Example 1 A cobalt bonded tungsten stub was provided with an annealed nickel disc deposited on the surface. A pressure of 40N/ ^mm2 was applied to the surface coated with nickel, and the temperature was increased.
The temperature was raised to 900℃. These conditions were maintained for 20 minutes. Thereafter, the exposed surface of the nickel layer was polished with a diamond abrasive tool. The thickness of the nickel coating was 120μ.

Then essentially aluminum nitride and/or
A disc-shaped cubic boron nitride compact with a second phase consisting of aluminum diboride is attached to the stub by first contacting the main flat surface of the compact with the nickel layer on the stub. Joined.
A transverse pressure of 170 N/mm ² was applied to the compact and stub to press them together and raise the temperature of the interface, ie the nickel layer, to 920°C. This process
It was carried out in a vacuum of 10 ^-4 Torr. 200 these conditions
Lasted for minutes.

This diffusion bonding technique produced an excellent bond between the compact and the carbide stub. The shear strength of the joint was measured and found to be approximately 110N/mm ² . The thickness of the bonding layer between the backing and the stub is
It was about 120μ.

Example 2 The same as described in Example 1 except that the following conditions were used: working pressure: 170 N/ ^mm2 , working temperature: 950°C, and duration: 30 minutes when joining a nickel-coated stub to a molded body. I performed the following operations.

Excellent bonding was also achieved between the molded body and the stub.

[Brief explanation of drawings]

FIG. 1 is a side cross-sectional view of the combined product used in the method of the present invention, FIG. 2 is a perspective view showing a cross section of a part of the combined product of FIG. 1, 20 is a combined product, 22 is an enclosure, 24 is a groove (or cavity), 26 is a recess, 28 is a steel holding base,
30, 32 are Nimonik wedges, 34 is a wire, 3
6 is a filling element, 38 is a wedge surface, 40 is an enclosure surface, 42 is a tool handle, 44 is an abrasive molded body,
46 is a thin metal layer.

Claims (1)

[Scope of Claims] 1. A method for joining an abrasive compact to a metal-containing holder, comprising: (a) nickel, copper, cobalt, iron, or an alloy containing one or more of these metals; (b) bringing the compact and the carrier together such that the metal layer is in contact with the surface of the compact; (c) applying transverse pressure thereto to form the compact; (d) raising the temperature of the metal layer to a temperature in the range of 650-950°C; and (e) sufficient to cause diffusion bonding between the compact and the holder. maintaining the pressure and temperature for a period of time and performing steps (d) and (e) in an inert atmosphere, wherein the abrasive compact is a cubic boron nitride compact or a diamond compact; The above joining method, wherein the holding body is made of sintered tantalum carbide, sintered tungsten carbide, sintered titanium carbide, or a mixture thereof. 2 The transverse pressure applied to the molded body and the holding body is
2. The method according to claim 1, characterized in that the pressure is in the range from 40 N/mm ² to 300 N/mm ² . 3. Process according to paragraph 1 or 2 above, characterized in that the pressure and temperature are maintained for a period of from 5 minutes to 360 minutes. 4. Process according to item 3 above, characterized in that the pressure and temperature are maintained for a period of from 5 minutes to 35 minutes. 5 After joining the molded body and the holding body in step (b), they are combined into an enclosure having a cavity therein and an expansion body which has a coefficient of thermal expansion larger than that of the enclosure within the cavity. and the temperature of the combined product is increased to the desired temperature in step (d) to expand the expandable body, and the molded product and the holding body are heated in step (c). Any one of the above items 1 to 4, characterized in that a desired cross-sectional pressure is applied.
The method described in section. 6. The method according to item 5 above, characterized in that the combined product is placed in a furnace to raise the temperature of the combined product. 7. The method according to item 5 or 6, characterized in that the enclosure is made of sintered carbide or a ceramic based on silicon nitride or zirconia. 8. The method according to any one of items 5 to 7 above, characterized in that the expander is made by Nimonic. 9. The method according to any one of the above items 1 to 8, characterized in that, before step (b), the surface of the metal layer that is brought into contact with the surface of the molded body is polished. 10. A time sufficient to deposit the metal layer on the surface of the carrier, apply cross-sectional pressure to the layer, raise the temperature of the layer to a temperature below the melting point of the layer, and bond the layer to the carrier. 10. The method according to any one of items 1 to 9 above, characterized in that the metal layer is bonded to the surface of the holder by maintaining pressure and temperature during the bonding process. 11 The pressure applied to the metal layer is 1N/mm ² to 200N/
The first above, characterized in that it is in the range of up to mm ²
The method described in item 0. 12. The method according to item 10 or 11 above, wherein the temperature at which the metal layer is heated is in the range of 700°C to 950°C. 13 Increase the pressure and temperature applied to the metal layer for 5 minutes.
13. The method according to any one of the above clauses 10 to 12, characterized in that the duration is 300 minutes. 14 Increase the pressure and temperature applied to the metal layer for 5 minutes.
14. The method according to any of the above clauses 10 to 13, characterized in that the duration is 30 minutes. 15. The method according to any one of items 1 to 14 above, wherein the holding body is a handle of a tool. 16. The method according to any one of items 1 to 14, wherein the abrasive molded body to be joined to the holder is a composite abrasive molded body. 17. The method according to item 16, characterized in that the holding body is made of sintered carbide.