JPH0416294B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to an improved SiC coated blade for a microtome, particularly to a SiC coated blade for a microtome that has significantly improved water retention properties, and a method for manufacturing the same. (Prior Art) Microtome blades used to prepare specimens for electron microscopy have conventionally been made of metal, glass, sapphire, and diamond. However, each of these has some drawbacks. In other words, metal blades require the cutting edge to be adjusted each time they are used, glass blades must be refinished each time they are used, and their lifespan is short; sapphire blades have poor cutting performance and have a short lifespan; The disadvantage is that the blades are expensive, and because they are produced by hand, productivity is low. In addition, some conventional methods have problems such as sagging, chatter, and other phenomena that occur in the microscopic examination results of specimens for electron microscopy, making them unsuitable for use in advanced medical fauna and flora departments. In conducting research on animals and plants, samples thinner than 500 Å are becoming necessary, but conventional methods have the disadvantage that it is impossible to collect samples thinner than 500 Å. (Structure of the Invention) The present invention relates to a SiC coated blade for a microtome that solves the above-mentioned disadvantages. The present inventors previously proposed a SiC coated blade for microtome in which a substrate is coated with crystalline silicon carbide and a method for manufacturing the same (Japanese Patent Application No. 60-49545), and improved the conventional drawbacks. As a result of their research, they succeeded in creating a microtome blade with significantly superior water shedding performance, leading to the present invention. The first invention of the present invention relates to a SiC coating blade for a microtome, which is formed by coating an ultra-thin film of olive oil or oleic acid on a substrate coated with crystalline SiC, and the second invention is a manufacturing method thereof. , an amorphous SiC film formed by plasma vapor deposition on a substrate is heat-treated at a temperature of 700 to 1250°C to crystallize the film, and after the heat treatment, the substrate is soaked in olive oil or oleic acid. This method is characterized by immersion. The SiC coated blade for a microtome of the present invention is a substrate coated with crystalline silicon carbide, but this substrate may be of a conventionally known type, including metals such as stainless steel and cemented carbide, glass, Examples include saphire. If the crystalline hydrocarbon film coated on this substrate is less than 50 Å thick, it is too thin and unreliable, and if it is more than 500 Å, it becomes impossible to collect a sample for electron microscopy.
The range is preferably 80 to 200 Å. In addition, to form an ultra-thin film of olive oil or oleic acid on a crystalline silicon carbide coating, immerse the crystalline silicon carbide coating with a surface temperature of 50°C or less in olive oil or oleic acid for 10 minutes or more immediately after heat treatment. It is obtained by taking it out and washing it with a known solvent such as methanol, hexane, acetone, ethyl acetate, etc. for 20 to 80 minutes. Soaking time 10
If the cleaning time is less than 20 minutes, the coating of olive oil and oleic acid will not be complete and the microscopic results will sag or chatter.If the cleaning time is less than 20 minutes, there will be residual amounts of olive oil and oleic acid, and if the sample thickness is less than 500Å. No. If it takes more than 80 minutes, the speculum results will be dull.
Chatter can be seen. Preferably, the soaking time is preferably 40 to 80 minutes, and the washing time is preferably 30 to 60 minutes. The crystalline silicon carbide coating of the present invention may be made by any method, but
It is obtained by forming a film of amorphous silicon carbide on a substrate by a plasma vapor deposition method of a silane compound, and then heating the film. This plasma vapor deposition method is also carried out by installing a substrate in a reactor, introducing the silane compound into the reactor as a mixed gas of hydrogen or argon gas as a carrier gas, and then lowering the internal atmospheric pressure to 1 Torr or less. Then, high-frequency power is applied to this to generate plasma in the system, whereby the silane compound is thermally decomposed by contact with the plasma flame and amorphous silicon carbide is generated. By heat-treating this, crystalline silicon carbide can be obtained. The heat treatment temperature is preferably in the range of 700 to 1250C. The silane compounds used here include a mixture of monosilane (SiH ₄ ) and a hydrocarbon, monomethylsilane (CH ₃ SiH ₃ ), dimethylsilane [(CH ₃ ) ₂ SiH ₂ ], trimethylsilane [(CH ₃ ) ₃ SiH], tetramethylsilane [(CH ₃ ) ₄ Si]
However, this is the general formula (CH ₃ ) _a Si _b H _c
and a, b, c are 1<b<4, a+1
It is preferable to use a methylhydrodiene polysilane having a number satisfying ≦2b+1, 1<c≦2b+1, and a+c=2b+2, and examples of the methylhydrodiene polysilane include the following.

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[Formula] Note that the plasma in the above may be generated within a high frequency electromagnetic field of 1 to 30 MHz, and the working gas may be argon gas as a monoatomic molecule gas or hydrogen gas that does not inhibit the reaction. Contamination with acidic gases must be avoided as this will lead to oxidation of the silicon carbide produced. Next, the cutting edge for a microtome must have a sharp cutting edge angle in order to have good cutting characteristics, but in the case of a SiC coated blade for a microtome,
A suitable angle between the two surfaces forming the edge line is 15° to 70°. If the angle is less than 15 degrees, tooth loss is likely to occur, and if the angle is more than 70 degrees, the cutting performance will be significantly reduced.
Preferably it is 30° to 50°. Next, examples of the present invention will be given. Example 1 (Manufacture of SiC coated blade for microtome) An artificial sapphire single crystal was processed into a shape in which the angle between the two faces forming the ridgeline for the blade edge was 45°, and after washing with pure and isopropyl alcohol and drying, 2 of the angle of the cutting edge with respect to the flow direction of the gaseous mixture in a reactor having a pair of discharge electrodes inside.
It was set up so that the equal dividing lines were parallel. Next, the pressure inside this reactor was evacuated to 5×10 ² Torr, and then gaseous tetramethyldisilane [CH ₃ ) ₄ Si ₂ H ₂ ] and hydrogen gas as a carrier gas were introduced therein, and the reactor was heated under gas flow. The pressure inside the reactor was adjusted to 0.1 Torr, and in this atmosphere, 13.5MHz high-frequency power (30W) was applied between the electrodes to generate a glow discharge, and this plasma caused a vapor-phase deposition reaction. , a plasma-polymerized film of amorphous silicon carbide with a thickness of about 100 to 150 Å was formed on the surface of the artificial saphire. Next, take out this artificial sapphire from the container,
After cleaning, the artificial sapphire blade was heated in a heat treatment furnace at 1000℃ for 30 minutes and then slowly cooled, and the resulting artificial sapphire blade was examined for scratches and the crystal structure of the deposited silicon carbide using an optical microscope and an X-ray diffraction device. Upon examination, it was confirmed that this coating film was made of crystalline silicon carbide without any flaws. This slowly cooled artificial sapphire blade is made into oleic acid.
Soak for 60 minutes, remove and wash with hexane for 30 minutes.
A cutting test and a 6000x magnification microscopy test were conducted on the artificial sapphire blade obtained, and it was confirmed that the water retention property was much better than that of the conventional blade. (Cutting test of SiC coated blade for microtome) Using the SiC coated blade for microtome, which was obtained by coating the artificial sapphire obtained above with crystalline silicon carbide and treating it with oleic acid and hexane, an organ sample was cured with epoxy resin. When cutting out a microscopic sample, we were able to extract a section with a thickness of 500 Å, which was confirmed to have the same accuracy as conventional microtome blades made of sapphire or diamond. . (Water retention performance test of SiC coated blade for microtome) Organs cured with epoxy resin were used to coat the artificial sapphire obtained above with crystalline silicon carbide and treated with oleic acid and hexane. A section with a thickness of 500 Å is taken from the sample, and this section is examined under a microscope with a magnification of 6,000 times to check whether there are any sag or titan shapes on the surface of the section. Since no formation of this shape was observed, the results of this microscopic examination were used to evaluate the water deposits.
This is because the generation of these shapes is seen in the conventional blades made of saphire and diamond for microtomes, but in the case of the SiC coated blade for microtomes of the present invention, these shapes are not generated. It was confirmed that this blade was superior to the microtome blade available from . Example 2 An artificial sapphire having a blade angle of 60° was treated in the same manner as in Example 1 to form a plasma polymerized film of amorphous silicon carbide on the surface of the artificial sapphire. this
Heat treatment was performed at 1000°C for 30 minutes to crystallize the silicon carbide, followed by slow cooling, and when the temperature reached 50°C, it was immersed in olive oil for 60 minutes. Thereafter, it was taken out, washed with ethyl acetate for 60 minutes, and dried. The obtained SiC coated blade for microtome was subjected to the same cutting test as in Example 1 and a microscopy test at 6000x magnification, and the results showed that the section of the sample was in good condition with no sag or chatter observed compared to the conventional one. It was confirmed that

[Brief explanation of drawings]

FIG. 1 shows a schematic vertical cross-sectional view of a SiC coated blade for a microtome according to the present invention. 1...Substrate, 2...SiC coating film, 3...
...Oleic acid ultra-thin film.

Claims (1)

[Claims] 1. A SiC coated blade for a microtome, which is formed by coating an ultra-thin film of olive oil or oleic acid on a substrate coated with crystalline SiC. 2 Amorphous material is deposited on the substrate by plasma vapor deposition method.
Production of a SiC-coated blade for a microtome, characterized in that a SiC film is formed, then heat treated at a temperature of 700 to 1250°C to crystallize the film, and after the heat treatment, the substrate is immersed in olive oil or oleic acid. Method.