JPH0133309B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a metal bonded diamond sintered body which is particularly suitable for grinding lenses such as pellets or wheels. Conventionally, copper-tin based metal bonded diamond sintered bodies have been widely used for the above-mentioned purposes. These copper-tin based metal bond sintered bodies have the drawbacks of a low cutting ratio, that is, a short life, and a low cutting amount. Nickel-based metal-bonded diamond sintered bodies other than copper-tin-based ones cause rapid graphitization of the diamond due to the high melting point of nickel.
Sintering requires a temperature of 1000°C or higher, but by making the particle size of the nickel powder relatively fine, low-temperature sintering was possible, and a sintered body with improved diamond retention and excellent grindability was developed ( Special request 1977
−159153). Furthermore, in order to prevent the clogging phenomenon that occurs during long-run grinding of this nickel bond sintered body, an element that forms an intermetallic compound with the base is added to the nickel base. A metal-bonded diamond sintered body with improved cutting ratio and cutting amount was developed by dispersing and precipitating a compound (patent application 1983-
No. 77787). However, the latter nickel-based metal bond sintered body has the disadvantage that the amount of cutting varies greatly due to variations in the surface precision of the material to be cut due to the previous process. The present invention further improves these nickel-based metal-bonded diamond sintered bodies, and provides a metal-bonded diamond sintered body in which part of the nickel is replaced with relatively inexpensive copper, and at the same time, variation in cutting amount is suppressed. The purpose is to provide the following. That is, the present invention provides a metal bond containing 0.2 to 3 wt% of one or more of phosphorus or sulfur and 2 to 30 wt% of copper, with the balance being nickel, and a diamond of 1 to 40 μm dispersed within the metal bond. This is a metal bonded diamond sintered body containing 0.1 to 10 wt%. The explanation of each additive component in the present invention and the reason for limiting the content of each component are as follows. First, nickel mechanically holds diamond powder as the main component of the matrix. Incidentally, nickel, which is the main component of the matrix, may be replaced with cobalt as the case requires, and by doing so, almost the same effect as in the case of nickel-based material can be obtained. Copper forms a solid solution in nickel and facilitates the precipitation of intermetallic compounds. If it is less than 2wt%, the amount of cutting will vary greatly, and if it exceeds 30wt%, the amount of cutting will decrease. Phosphorus or sulfur also reacts with the copper-containing nickel solid solution of the matrix, promoting the formation of fine intermetallic compounds that are susceptible to wear and increasing the hardness of the bond. The amount of these elemental powders added is such that the intermetallic compound formed by the addition is sufficient to contribute to grinding. For this purpose, by adding 0.2 to 3 wt % of one or more elements such as phosphorus or sulfur, an appropriate amount of intermetallic compounds can be precipitated. These additive elements are usually used alone, but two types may be used in combination. Note that the group of these additive elements includes magnesium and the like and has a similar ability to form an intermetallic compound, but these elements are less preferable than the exemplified elements from the point of view of melting point. The above-mentioned nickel, copper, phosphorus, or sulfur element powders have a particle size of 100 mesh or less. This combined with the formation of intermetallic compounds by each component element and the replacement of some of the relatively high-melting-point nickel powder with copper powder made it possible to perform low-temperature sintering and avoid graphitization of the diamond. Become. The diamond powder used in the present invention is 1
Add 0.1-10wt% of ~40μ. but,
Depending on the application, the particle size and amount of diamond powder added can be freely changed. The sintered body of the present invention is prepared by adding a small amount of each component powder, diamond powder, and if desired, a lubricant such as zinc stearate or lithium stearate, mixing, pressing, and then sintering in a non-oxidizing atmosphere. Although the usual powder metallurgy method is optimal in terms of mass production, it can also be manufactured by a hot pressing method or an electric sintering method. In the sintered body thus obtained, the added copper is dissolved in solid solution in the nickel base, which promotes the formation of an intermetallic compound between the base and the intermetallic compound-forming element, and also promotes sintering, and the metal in the matrix. It is thought that the dispersion of intermediate compounds is also made uniform. Furthermore, by appropriately interposing copper in the intermetallic compound, a metal bond that is hard and wears uniformly at an appropriate rate is formed, eliminating the clogging phenomenon during long runs due to pores that occur after the formation of the intermetallic compound. The amount of cutting increases due to the self-dressing effect of the metal bond, and the variation in the amount of cutting is also reduced, making it possible to obtain a metal bonded diamond sintered body that is relatively inexpensive and extremely desirable in practice. Examples are shown below. Example Using nickel powder with an average particle size of 5μ and other raw material powders with -250 mesh, these were adjusted to have the composition shown in the following table, and 8 to 8
1% of 16μ diamond powder was added and then sintered to obtain metal-bonded diamond sintered bodies called diamond pellets each having a diameter of 16 mm and a thickness of 3 mm, and a cutting performance test was conducted. Note that Sample 4 in the table is a comparative example using a conventional copper-tin metal bond. Each of these specimens was polished using a high-speed polisher to reduce the diameter
Paste 20 pellets into a 100mm pellet dish.
GC #500 and GC #280 test pieces of a grinding type called BK-7 with a diameter of 60 mm were applied with a load of 20 kg.
After adjusting the surface in advance, grinding was performed for 12 seconds, and the cutting amount and cutting ratio were determined. The results are shown in the table below.

[Table] From the above table, the metal-bonded diamond sintered body according to the present invention is much superior to the conventional copper-tin-based ones in terms of cutting amount and cutting ratio, and the variation in cutting amount is also small, making it suitable for practical use. It turns out to be very useful. Such a metal-bonded diamond sintered body according to the present invention can be expected to have a wide range of applications, including not only lens grinding but also glass, ceramics, and metal semiconductor grinding.

Claims (1)

[Claims] 1 One or more types of phosphorus or sulfur 0.2~
A metal bond containing 3 wt% and 2 to 30 wt% copper, with the remainder being nickel, and 0.1 to 10 wt of diamonds of 1 to 40μ dispersed within the metal bond.
A metal bonded diamond sintered body containing %.