JPS6081009A - Manufacture of cubic-crystal boron nitride compound - Google Patents

Abstract

PURPOSE:To obtain the fine cubic-crystal type boron nitride with an easy and simple operation by heating a boroamino polymer shown by a specified formula. CONSTITUTION:A boronamino polymer shown by the formula (n is >=3 integer) as it is or dissolved in an adequate solvent is coated on the surface of a substrate, and the material is heated to <=170 deg.C under ordinary pressure. A cubic- crystal type boron nitride as an excellent tool material for cutting, prolishing, etc. can be extremely easily obtained by this method. In addition, the boroamino polymer used in this case is obtained by allowing hydrogenated alkali metal borane to react with ammonia, ammonium halide, etc. at 77 deg.K in ethyl ether, and then elevating the temp. of the reaction mixture to room temp.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing cubic boron nitride compounds. Cubic boron nitride compounds are attracting attention as tool materials for cutting, grinding, etc.

Conventionally, such cubic boron nitride compounds have been obtained by treating hexagonal boron nitride compounds at high temperatures and high pressures. Alternatively, it was produced by a catalytic process using a catalyst.

However, in these methods, those requiring high temperature and high pressure cannot be called industrial methods even from an economic point of view, as the container equipment must be dependent on the equipment. In those that use a catalyst, it is difficult to obtain cubic single crystal boron nitride, or even if it is obtained, it does not have a 7-year edge.
It has disadvantages such as poor cutting and grinding properties.

This invention provides polyamino polymer H+B H under normal pressure.
The present invention was based on the finding that cubic boron nitride can be produced by heating -NH-)nH.

That is, a polyamino polymer represented by the formula H-(-BH-NH-)nH is applied to the surface of a substrate in its 1\ form, or dissolved in an appropriate solvent, and then heated to form cubes very easily. Crystalline boron nitride can be obtained. , the polyamino polymer used herein is made as follows. That is, a hydrogenated alkali metal borane, such as nium, is heated to an ether temperature of 77.
After reacting at 30°C, the product polyamino monomer polymerizes to form a polyamino polymer by increasing the temperature of the reaction mixture to room temperature.

Heating requires a temperature of at least 1700°C or higher and 2000°C.
The above method is preferable in that the generated boron nitride is completely transformed into a cubic crystal type. When applied by dissolving in a solvent, examples of the solvent include dimethylformamide, dimethylacetamide, dimethyl sulfoxide, HMPA, etc., and examples of the substrate to be applied include aluminum oxide. explain in detail.

Example 1 10 fl of a polyamino polymer was dissolved in 7 poml of dimethylformamide, and this was repeatedly applied to the surface of α-aluminum oxide three times.

After air drying, it was heated at 200 CVC for 2 hours.

It was observed that a white solid was formed on the surface of α-aluminum oxide. This material was confirmed to be cubic boron nitride by X-ray diffraction.

The particle size is 0.1-1.

X-ray diffraction data 2θ d 1.45.1° 2.09 2, 74.0° 1,28 8, 90.0° 1.09 Reference Example The polyamino polymer used in the present invention was prepared as follows. was synthesized.

Boron hydride lithium 220g, ammonium chloride 540g
g was added to 2000 ml of ethyl ether and reacted at a temperature of 77°. The reaction was complete when hydrogen evolution ceased. The reaction mixture was then heated to room temperature, generating hydrogen gas and forming a polyamine polymer.

Lithium chloride was removed from the resulting reaction mixture by washing with water to obtain a polyamino polymer.

Yield 95%

Claims (1)

[Claims] A method for producing a cubic boron nitride compound, which comprises heating a polyamino polymer represented by the formula % to a temperature of 170° C. or higher under normal pressure to obtain a cubic boron nitride compound. [In the formula, n represents an integer of 3 or more]