JPH05285842A - Manufacture of diamond wheel - Google Patents

Abstract

PURPOSE:To provide a high mechanical strength by a method wherein the surface of a wheel made of an Al alloy is modified and treated by means of a carboxylic acid dielectric water solution after the surface of the wheel is covered with an Al film, and thereafter electroless plating of Mo is applied, and the surface thereof is covered with a continuous layer of diamond multicrystal particles. CONSTITUTION:An Al film is formed on the surface of an Al alloy being a base material for a wheel by a vacuum deposition method and a spattering method. After the surface of the Al film is modified and treated by means of an organic carboxylic acid dielectric water solution, electroless Mo plating is applied on the Al film. A continuous layer of diamond multicrystal particles is caused to grow on an Mo plating Al alloy base material through a gas phase method or by means of a micro CVD or a plasma CVD device. Namely, a diamond layer wherein the multicrystal particles of diamond are firmly bonded to each other and the large and small particles of multicrystal particles form an aggregate which is adhered to an Mo plated layer is formed. The drop and breakage of diamond particles owing to vibration and the impact of a polishing machine are reliably prevented from occurring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a diamond wheel having excellent grinding performance.

[0002]

2. Description of the Related Art Diamond wheels used for polishing, grinding, cutting, drilling, and the like had diamond abrasive grains adhered to the wheel surface with an adhesive. Grinding performance is deteriorated such that abrasive grains are detached from crushing and clogging occurs, and the wheel has a drawback that heat is generated and the material to be ground is also damaged or damaged. The diamond abrasive grains used in the diamond wheel are abrasive grains composed of natural or artificial diamond single crystals, and have excellent cutting performance, but have the drawback of being weak against vibration and impact. On the other hand, polycrystalline diamond particles have high fracture strength and are particularly suitable for heavy grinding. However, polycrystalline diamond particles were rarely produced in nature and never used industrially. Generally, most diamond wheels have relatively large dimensions, and the peripheral speed is 500 ~.
Since it is as large as 300 m / min, many aluminum alloys that are lightweight and have mechanical strength are used for the wheel base material.

However, the gas phase micro
To apply diamond coating (including growth of polycrystalline particles and formation of thin film) by the CVD method, it is necessary to heat the substrate to 700 ° C or higher, especially 800 ° C or higher, but the melting point of the aluminum alloy is 660 ° C. Since it is in the vicinity, it has no heat resistance and is virtually impossible. On the other hand, it is known that the heat resistance of aluminum is remarkably improved by directly bonding a heat resistant metal or alloy to aluminum by sputtering, electroplating, or chemical plating. Mo-plated Al substrate ", Tsuda Laboratory, 19
According to [October 22, 1990], it is necessary for displacement plating by immersing the surface of aluminum in an aqueous solution containing an organic carboxylic acid derivative for 5 to 7 minutes at pH 7 and a bath temperature of 90 ° C for modification treatment. It is known that electroless molybdenum plating is possible after releasing an appropriate amount of various Al ⁺³ ions. However, aluminum alloys have the drawback that heat-resistant metals and alloys cannot be directly bonded by sputtering, electroplating or chemical plating.

[0004]

In order to generate diamond abrasive grains having excellent hardness and high adhesive strength on the surface of an aluminum alloy, it is necessary to precipitate polycrystalline diamond particles from the vapor phase. Therefore, in order to solve such a problem, the present invention aims to provide a diamond wheel having excellent grinding performance and high mechanical strength by growing polycrystalline diamond particles on the surface of an aluminum alloy wheel.

[0005]

Means for Solving the Problems As a result of the present inventors, in order to solve such problems, as a result of diligent examination of conditions for growing polycrystalline diamond particles on the surface of an aluminum alloy by using a vapor phase micro CVD method. The present invention has been completed with the knowledge that it is better to perform a specific pretreatment on the surface of an aluminum alloy base material. The gist of the invention is that the surface of an aluminum alloy wheel is coated with an aluminum film by a vacuum deposition method or a sputtering method. After coating, diamond is characterized by being modified with an aqueous solution of an organic carboxylic acid derivative, then electrolessly plated with molybdenum, and further coating the surface with a continuous layer of diamond polycrystalline particles by a vapor phase micro CVD method. It is in the wheel manufacturing method.

The present invention will be described in detail below. First, in the first step, aluminum is coated on the surface of an aluminum alloy, which is a base material of a wheel, to a thickness of 100 to 200 μm by a known vacuum vapor deposition method or sputtering method. Vacuum deposition of aluminum may be performed at room temperature under a vacuum of 5 × 10 ⁻⁴ Torr or less without heating the substrate. Further, the sputtering may be performed under substantially the same conditions as the vacuum evaporation.

As a second step, electroless molybdenum plating is applied on the aluminum coating. This electroless Mo plating may be carried out by a known method. If the surface of the aluminum alloy is immersed in an aqueous solution containing an organic carboxylic acid derivative at pH 7 and a bath temperature of 90 ° C for 5 to 7 minutes, it is necessary for displacement plating. ^Na Al ⁺³
A proper amount of ions are released and a so-called modification treatment is performed. Examples of the organic carboxylic acid derivatives include citric acid, succinic acid, tartaric acid, oxycarboxylic acids such as gluconic acid and salts thereof, amino acids, and polyaminocarboxylic acids such as EDTA. One or more of these may be used. Select and use. Then, in the electroless Mo plating bath, bath temperature 85 ~ 95 ℃, pH
Mo is continuously precipitated when immersed for 5 to 15 minutes under the condition of 6.5 to 7.5. This Mo plating thickness should be 0.2-1 μm,
If it is less than 0.2 μm, it becomes wrinkled, and if it exceeds 1 μm, it becomes uneconomical.

As the composition of the Mo electroless plating bath, ammonium molybdate or the like is used, 0.5 to 3 mol / liter of Mo, 4 to 15 mol / liter of an organic carboxylic acid derivative, and an electroless plating bath of ammonium chloride or the like. A stabilizer is 0.1 to 0.5 mol / liter, and ammonia or the like is used as a pH adjuster.

In the third step, Mo prepared as described above
Micro CVD or plasma CVD on plated Al alloy substrate
A continuous layer of polycrystalline diamond particles is grown by a vapor phase method using an apparatus or the like. In this case, the diamond wheel is usually used for rough finishing, for intermediate finishing and for upper finishing depending on the particle diameter of the diamond, so it is necessary to adjust the particle diameter of the polycrystalline diamond particles. A method is used in which the surface of a base material, which is a bed for producing diamond synthesized from a gas phase, is preliminarily polished with diamond particles to be scratched and deposited. The average grain size of this polycrystalline diamond is preferably 20 to 100 μm for rough finishing, 6 to 12 μm for intermediate finishing, and 1 to 5 μm for upper finishing. The diamond thin film covering the Mo plating layer and strongly adhering the grown polycrystalline diamond particles is preferably 1-100 μm, and 1 μm is preferable.
If it is less than m, the adhesive strength will be insufficient, and if it exceeds 100 μm, the adhesive strength will be insufficient and peeling will occur easily.

In the fourth step, the diamond-coated wheel base material produced in the third step is joined to the base metal with an adhesive, welding or the like to form a diamond wheel. The aluminum alloy of the wheel base material is expressed by the composition formula (% by weight): Al-Si (Al: 86-90, Si: 10-14), Al-Mg (Al: 90
~ 99.8, Mg: 0.2 ~ 10), Al-Si-Mg (Al: 70 ~ 89.8, Si: 10 ~ 1
4, Mg: 0.2-10) and the like, but Al-Si and Al-Si-Mg are preferable in terms of strength and hardness.

The diamond wheel manufactured through the above steps has diamond polycrystal particles strongly adhered to the aluminum alloy base material, and vibrates like a conventional product.
It overcomes the drawback of being vulnerable to impact and has a high breaking strength, especially for heavy grinding.

[0012]

EXAMPLES The embodiments of the present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. (Example) An aluminum alloy (87.7Al-12.0Si-0.3Mg each weight) plate having an outer diameter of 20 mm, an inner diameter of 16 mm and a thickness of 10 mm was used as a wheel base material, and Al was vapor-deposited on its surface by a vacuum vapor deposition method. Vacuum evaporation system EBX-60 type (Nippon Shinku Technology Co., Ltd.)
(Product name) reaction chamber and vacuum pump for 10 ^-5
After evacuating to Torr, a current of 350 mA is applied to the electron beam heater to heat the pure Al material, and the Al film is evaporated to a thickness of 1
It was set to 00 μm. Next, this substrate is degreased with detergent (70 ° C x 2 minutes), alkaline degreased (25 ° C x 1 minute), and modified (sodium citrate 5 mol / liter) is immersed in an aqueous solution at pH 7 and bath temperature 90 ° C for 5 minutes. ), Mo electroless plating (bath composition: ammonium molybdate 1 mol / l, ammonium chloride 0.2 mol / l, sodium citrate 9 mol / l immersed in a solution at 90 ° C for 10 minutes). A material was produced. Next, in order to coat this base material with diamond polycrystal particles with a micro CVD device, as a pretreatment, diamond powder with an average particle size of 0.25 μm was placed in a 0.5 wt% ethyl alcohol aqueous solution, and was ultrasonically cleaned for about 30 minutes. Polished. Then, after it was washed with acetone, internal take this substrate in a reactor of a micro CVD apparatus was evacuated to 10 ^-2 Torr, CH ₄ 2,
A mixed gas of H ₂ 98 each volume% was introduced, the internal pressure was set to 25 Torr, and a microwave of 2.45 GHz was applied at 1.2 KW for about 50 hours to perform diamond coating on only one surface. The wheel base material thus produced was adhered to an aluminum alloy base metal with an acrylic adhesive to produce a diamond wheel. Next, a grinding test was conducted as follows through a shaft having a diameter of 16 mm, and the results are shown in Table 1.

Grinding test Surface grinder: table traverse: 20 m / min, wet grinding with water, diamond wheel peripheral speed: 1,300 m / mi
n. Workpiece: Al-Si alloy (88Al-12Si each weight%). Depth of cut: The depth of cut is evaluated by measuring the grain size (μm or mm) of the grinding powder generated by grinding. Crushability: The grinding condition is evaluated by visual observation. Oversized: Can be ground very well. Large: Can be polished well. Concentration: The content of diamond abrasive grains is expressed by weight%. (The relationship with cts / cc is 50% = 2.2cts / cc, 75% = 3.3ct
s / cc, 100% = 4.4cts / cc, 150% = 6.6cts / cc)

(Comparative Example) Grinding in the same manner as in Example using a commercially available diamond wheel of the same size (manufactured by Sankyo Diamond Industrial Co., Ltd., model number D140H100R30K-123, diamond grain size: 140 #, concentration degree: 100) Test,
The results are also shown in Table 1.

[0015]

[Table 1]

[0016]

EFFECTS OF THE INVENTION According to the present invention, the polycrystalline particles of diamond are tightly bound to each other, and large and small particles of polycrystalline particles are formed on the diamond thin film which is aggregated and adheres to the Mo plating layer. Therefore, a diamond wheel for heavy grinding is obtained which is less likely to have diamond particles falling off or cracking due to shock due to vibration or shock of the polishing machine, and thus has a very high industrial utility value.

Claims (1)

[Claims] 1. A wheel surface made of an aluminum alloy is coated with an aluminum film by a vacuum deposition method or a sputtering method, modified with an aqueous solution of an organic carboxylic acid derivative, then subjected to electroless plating of molybdenum, and the surface thereof is vaporized. A method for producing a diamond foil, which comprises coating a continuous layer of polycrystalline diamond particles by a phase micro CVD method.