JPH0197839A - Blade coated with diamond-like carbon - Google Patents

Abstract

PURPOSE:To support the edge of a blade of a hard material with a material having adhesiveness and thereby to obtain a blade coated with diamond-like carbon and thereby made excellent in abrasion resistance and a cutting property, by coating a base with amorphous diamond-like carbon containing hydrogen prescribed in the atomic number ratio, so that the diamond-like carbon be the edge of the blade. CONSTITUTION:A base 1 of an edged tool made of steel, stainless steel, hard metal, ceramics, glass or the like is coated with amorphous diamond-like carbon 2 containing hydrogen of 0.5-20% in the atom number ratio so that the diamond-like carbon 2 be the edge of a blade. This diamond-like carbon 2 is applied on a face and a flank of the blade, or on the edge of either the face or the flank of the blade. A diamond-like carbon layer held two bases 1 between forms an edge line being the edge of the blade, and the two bases constitute the face and the flank respectively.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention provides a blade whose cutting edge is made of hard diamond-like carbon, which has excellent durability, corrosion resistance, and machinability, and is particularly suitable for plastics and ecological materials. It relates to a blade suitable for cutting organic materials such as samples.

[Conventional technology]

Medical knives and microtome blades are known as conventional knives for cutting organic materials such as plastics and biological samples.

Steel and stainless steel were used for medical knives such as scalpels, scalpels, and dissecting knives. Medical knives must always maintain good cutting performance and must be sharpened frequently or -
There was a complication in that the blade had to be discarded and replaced with a new one every time it was used.

The microtome blade holds several microscopic sections for optical microscopy.
There was a steel blade that cuts out 100-200mm thick sections, and a natural diamond blade and glass blade that cut out ultra-thin sections for electron microscopic observation at 100 to 200mm thick. The edge of the steel blade for microtome wears easily, so if it is used repeatedly, it must be sharpened with a scalpel each time, and the edge is easily damaged by rust. On the other hand, the natural diamond blade and glass blade for a microtome must not have any flaws that exceed the extent that would interfere with electron microscopy observation. However, manufacturing natural diamond blades requires special skill and know-how, the blade length is only about 3 cranes long, and they are extremely expensive. Glass blades are made of cheap materials, but their performance is problematic.You cannot check whether the blade is good or not unless you make it and cut it.Even if it is well made, its performance deteriorates after cutting it several times. The observer himself/herself must make one each time he or she cuts out a section and observes it. More recently, Japanese Patent Application Laid-Open No. 62-2133 discloses a diamond coated blade for a microtome. According to the example, this is a method in which a 50 to 500 diamond film is deposited on a heated sapphire substrate using hydrocarbon gas as a raw material by microwave CVD, and then the hydrogen in the film is removed by heat treatment. It is. Although it is more durable than conventional products, the manufacturing method for diamond film requires two steps: coating and heat treatment.

The cutting performance of a blade is controlled by the hardness of the blade and the shape of the cutting edge. However, blades made of hard materials such as glass or diamond are less likely to wear out during use, but they have the drawback of being brittle and easily chipping.

For cutting ultra-thin sections for electron microscopy, priority is given to blades with high hardness and resistance to wear, while for cutting sections for optical microscopy and medical knives, blades that are resistant to chipping even when cutting thick samples are prioritized. Character has been prioritized.

[Problem that the invention seeks to solve]

The present invention provides a blade that satisfies the two conditions of being hard to wear and hard to chip, and a method for manufacturing the same.

[Means for solving problems]

The present invention relates to a blade in which a substrate is coated with amorphous diamond-like carbon containing 0.5 to 20% hydrogen in terms of atomic ratio, and the diamond-like carbon serves as a cutting edge.

The diamond-like carbon referred to in the present invention is as follows. It has a hardness similar to that of natural diamond, is amorphous, and its electron diffraction image shows a halo pattern. Also, in the Raman spectrum, 1580 (near J-' and 1360 cm-
It shows a broad peak characteristic of amorphous materials near '. The elemental composition is mainly carbon and contains 0.5 to 20 atom% hydrogen. The presence of hydrogen was confirmed in the diamond-like carbon film of the present invention by secondary ion mass spectrometry, and quantification by melt analysis and N resonance nuclear reaction revealed that it contained 0.5 to 20 atom% of hydrogen. It was confirmed that the Vickers hardness was 20001.
1v to 900011v.

Diamond-like carbon is considered to be amorphous like amorphous silicon, and hydrogen is bonded to dangling bonds of carbon atoms.

It is presumed that due to the presence of an appropriate amount of hydrogen, diamond-like carbon exhibits high hardness comparable to that of natural diamond. If there is too much hydrogen in the diamond-like carbon film, it will become a soft organic film, and if there is too little hydrogen, it will become graphite. Therefore, the proportion of hydrogen in the film is 0.5 to 20a.
tom%, preferably 2 to 8a to I11%.

The method for manufacturing the diamond-like carbon film used in the present invention is the ionization vapor deposition method (Japanese Patent Application Laid-Open No. 59-174507), from the viewpoints of adhesion of the film to the substrate, uniformity of film quality, smoothness of the film surface, and productivity. and Japanese Patent Publication No. 59-174508
No. 2) is preferred.

FIG. 2 shows a diagram of the principle of the ionization vapor deposition apparatus. Hydrocarbon gas as a raw material is introduced into a vacuum, ionized by a glow discharge and a red-hot filament 10, and extracted by the expanding magnetic field of an electromagnet 11. This part covered with electromagnets is called the ion source. The extracted ions are accelerated toward the substrate 13 to which a negative bias voltage is applied, collide with the substrate, and are deposited. As raw material gas, methane,
Hydrocarbons that can be easily introduced as a gas such as ethane, acetylene, and benzene may be used, but methane is particularly preferred. Hydrogen gas may be used as a diluent gas for the above raw material gases. However, in the ionization vapor deposition method, the hydrogen content in the film depends on the bias voltage of the substrate and does not significantly depend on the proportion of hydrogen gas in the source gas. The pressure inside the container may be between lo-4 and 10'' Torr, but 10
-" Torr is desirable. The substrate temperature is room temperature (
A good thin film is formed when the temperature is between 25°C and 600°C. Within that range, especially room temperature (about 25℃) to 300℃
is the preferred range. When the substrate temperature is higher than 600°C, the film that is created tends to become graphite-like, and even if diamond-like carbon is formed, when the temperature is returned to room temperature, the strain between the substrate and the film becomes large, and the film may deteriorate during use. It becomes easy to peel off.

The substrate bias voltage is set at -50V to -1500V, with a preferable range of -1500V to -100[alpha]V. When a hydrocarbon ion is accelerated by a bias voltage and collides with a substrate, the collision energy causes the C-
The H-bond is broken and the hydrogen atom is ejected. The rate at which these hydrogen atoms are ejected depends on the kinetic energy of the colliding ions, that is, the bias voltage; if the bias voltage is too small, the hydrocarbon ions will not be sufficiently decomposed on the substrate surface, resulting in a soft organic film with a large amount of hydrogen. If the bias voltage is too high, the film becomes graphite-like, and furthermore, sputtering of the film occurs. The magnetic flux density in the ion source is set in the range of 1000 to 1000G, with a preferable range of 300G to 500G. Since detailed manufacturing conditions vary depending on the arrangement of the gas inlet in the apparatus, the size of the ion source, the position of the substrate, etc., it is desirable to set optimal conditions as appropriate.

The base of the cutlery of the present invention may be of conventionally known materials, such as steel, stainless steel, cemented carbide, metallic silicon, ceramics, glass, and sapphire.

The diamond-like carbon that forms the cutting edge must have sufficiently strong adhesion to the substrate, and the diamond-like carbon film of the present invention has particularly strong adhesion to metal silicon, silicon carbide, tungsten, etc. When coating a weak substrate, it is preferable to coat a diamond-like carbon film with the above-mentioned material interposed between the substrate and the substrate. When coating diamond-like carbon on the base cutting edge formed on the blade in advance, the film thickness should be 50 to 500 mm, preferably 50 to 200 mm, to the extent that the sharpness of the blade edge is not impaired.
Good range of people. If the base body is coated with diamond-like carbon and then processed and formed into a blade, the film thickness should be between 50 and 2
It may be between 0 μm. In this case, in order to make the diamond-like carbon form the ridge of the cutting edge, it is necessary to
It is easy to process a film thickness in the μm range, but when manufacturing a blade for cutting relatively hard and thick samples, 50 to 500 people are required.
A film thickness in the range of 0 is preferred.

In the present invention, of the two surfaces making up the blade, the surface that contacts the sample is called the flank surface, and the surface on the opposite side, on which the cutting piece slides, is called the rake surface. The angle formed by the flank and rake faces is called the wedge angle, and the ridge where the flank and rake faces intersect is called the cutting edge. FIG. 1 is a longitudinal cross-sectional view of the blade, and (A) shows a substrate 1, which will become the cutting edge, which has been previously processed into a sharp pyramid shape, and is coated with a diamond-like carbon film 2. (A) shows a processed substrate l coated with a diamond-like carbon film 2. In (1), a diamond-like carbon film 2 is sandwiched between two substrates, and the diamond-like carbon layer is processed to serve as a cutting edge.

〔Example〕

In all of the following examples, diamond-like carbon films were created by the ionized vapor deposition method. In each example, the cutting edge was examined using a scanning electron microscope before and after the cutting test.
It was observed under magnification of 0.000 times and it was confirmed that the diamond-like carbon layer on the cutting edge was not chipped or peeled off. The hardness is measured using Vickers hardness under a load of 1°. The film thickness is a value obtained by partially masking the layer in advance and measuring the difference in level after vapor deposition using a palpable surface roughness meter.

Example 1 A substrate with a thickness of 2mm was deposited on a 5mm thick Si single crystal (100) mirror surface at a substrate temperature of 150°C and a bias voltage of -900V.
9pm, hardness 840011v, hydrogen containing fi3atom
% diamond-like carbon film was coated. Cut a diamond glass cutter at the edge of the sample, break the sample from that point, and select the part where the wedge angle of the broken part is acute (Figure 1 (a)).Ultramicrotome (LKB) It was attached to the Ultrotome ■ (hereinafter the same). After that, the embedding resin for preparing thin sections was cut using the ultramicrotome. Good sections were obtained.

Example 2 The same Si single crystal surface as in Example 1 was polished in advance with alumina grains with a diameter of 0.03 μm in order to improve the adhesion of the film, and this was used as a substrate at a substrate temperature of 300°C and a bias voltage. -500v, thickness 0.5μm, hardness 3100Hv,
A diamond-like carbon film with a hydrogen content of 9 atom% was coated. The cross section of this sample was cut at a wedge angle of 3.
It was polished so that the angle was 0 degrees (Figure 1 (a)). When this blade was used to cut the embedding resin for preparing thin sections with an ultramicrotome, good sections were obtained.

Example 3 The surface of a 5-fin thick SiC plate (IBIDEN 5C850) was polished with diamond grains of 0.28 m in diameter, and this was used as a base.
Thickness: 2.5mm at substrate temperature of 300°C and bias voltage of -700v.
A diamond-like carbon film with a diameter of 0 μm, a hardness of 5000 Hv, and a hydrogen content of 5 atom% was coated, and the sample was cut and polished at a wedge angle of 45 degrees (see Figure 1).
stomach)). When this blade was used to cut the embedding resin for preparing thin sections with an ultramicrotome, good sections were obtained.

Example 4 A 7 μm thick SiC layer was formed on the surface of a 10 m thick isotropic graphite material (Kyowa Carbon MSG) by thermal CVD using silane gas and methane gas as raw materials.
A diamond-like carbon film with a thickness of 2.2 μm, a hardness of 5500 Hv, and a hydrogen content of 7 atom% was coated at 00°C and a bias voltage of -600 V. The sample was broken and the cross section was polished so that the wedge angle was 60 degrees. When this blade was used to cut the embedding resin for preparing thin sections with an ultramicrotome, good sections were obtained.

Example 5 A silicon single crystal block with a thickness of 511 mm was made with a blade length of 30 m.
, Processed and polished to a blade with a rust angle of 45 degrees.

This blade has a base temperature of 300℃, a bias voltage of -800V, a film thickness of 200 mm, a hardness of 2500 Hv, and a hydrogen content of 4a L.
on+% diamond-like carbon was coated (FIG. 1(A)). When this blade was used to cut the embedding resin for preparing thin sections with an ultramicrotome, good sections were obtained.

A comparison of the number of good sections obtained by continuously cutting the embedding resin for forming thin sections using the conventional glass blade and the blades of Examples 1 to 5 will be shown below.

Test Results Example 6 A TiN film with a thickness of 500 mm and a hardness of 2000 Hv was formed on the surface of a stainless steel plate with a thickness of 0.6 vsm by the holocathode ion blating method, and a substrate temperature of 300°C and a bias temperature of Film thickness 0.5μ at voltage -700V
A diamond-like carbon film having a hardness of 4000 Hv and a hydrogen content of 5 atom % was coated. This is processed and polished so that the wedge angle of the cutting edge is 30 degrees, and the blade length is 5.
c11. The cross-sectional structure of the knife was as shown in (a) in Figure 1.

Attach this blade to a sliding microtome and cut chicken to a thickness of 0.
When 5 fins were cut out, good sections were obtained.

Example 7 A TiN film having a thickness of 500 mm and a hardness of 2000 Hv was formed on the surface of a carbon steel plate with a thickness of 0.25 m in the same manner as in Example 6, and a substrate temperature of 200° C. and a bias voltage of -
At 800v, the film thickness is 2. (1'm + hardness 8500Hv, hydrogen containing i15atom% diamond-like carbon film 1
Create a strip of tm
A thick TiN film was coated over the entire surface. Next, after polishing this surface to make it uniformly flat, this surface has a thickness of 0.
25** carbon steel plates were bonded. This is cut so that the diamond-like carbon film part becomes the cutting edge, and polished so that the wedge angle of the cutting edge is 45 degrees.A blade with a blade length of 20 mm is made with a cross-sectional structure as shown in Figure 1. I made it. When this blade was attached to a sliding microtome and the chicken was cut into 0.5 fin thickness, good sections were obtained.

Below is a comparison of the number of good sections obtained by continuous cutting of chicken meat using the stainless steel conventional blade and the blades of Examples 6 and 7.

Test Results [Effects of the Invention] According to the present invention, it is possible to manufacture a blade made of a composite material, in which the cutting edge of a hard material is supported by a sticky material. The blade of the present invention is as hard as diamond and as hard to chip as steel, so it has superior durability, wear resistance, and cutting performance compared to conventional products, and is especially suitable for cutting organic materials such as plastics and ecological samples. This blade is suitable for The blade of the present invention significantly improves the drawbacks of precision cutting blades that require frequent blade replacement.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a diamond-like carbon coated blade of the present invention. FIG. 2 is a diagram showing the principle of the ionization vapor deposition apparatus. Namegi Figure 1 Figure 2

Claims (4)

[Claims] (1) A diamond-like carbon coating characterized in that amorphous diamond-like carbon containing 0.5 to 20% hydrogen by atomic ratio is coated on a substrate, and the diamond-like carbon is used as a cutting edge. blade. (2) A diamond-like carbon-coated blade according to claim 1, wherein the rake face, escape face, and cutting edge of the blade are coated with diamond-like carbon. (3) The diamond-like carbon-coated blade according to claim 1, wherein either the rake face or the rake face of the blade and the cutting edge are coated with diamond-like carbon. (4) The diamond-like carbon layer sandwiched between the two substrates forms a ridgeline that is the cutting edge, and the two substrates form the rake face and flank of the blade, respectively.
Diamond-like carbon coated blade as described in section.