CN1735716A

CN1735716A - Diamond-coated electrode and method for producing same

Info

Publication number: CN1735716A
Application number: CN 200480002092
Authority: CN
Inventors: 关裕一郎; 泉健二; 今井贵浩
Original assignee: Sumitomo Electric Industries Ltd
Current assignee: Sumitomo Electric Industries Ltd
Priority date: 2003-05-26
Filing date: 2004-05-25
Publication date: 2006-02-15

Abstract

A diamond electrode having a sufficiently low resistance is disclosed which is realized by increasing the amount of boron added thereto. A method for producing a high-performance, high-durability electrode is also disclosed by which adhesiveness between a diamond coating and a substrate and separation resistance during electrolysis are sufficiently increased. An electrode composed of a substrate and a diamond layer coating the substrate is characterized in that the electrode is composed of a base coated with diamond and the diamond contains boron in such an amount that the boron concentration is not less than 10,000 ppm but not more than 100,000 ppm. The base is preferably made of an insulating material.

Description

Diamond-coated electrode and preparation method thereof

Background technology

Be considered to obtain to have the method for big relatively surface-area and the polycrystalline diamond more cheap by the synthetic diamond that obtains of gas phase, and this diamond is used in the optical element application facet and as the scatterer that is used for electronic component and instrument than natural diamond or artificial single crystal's diamond of under ultra-high voltage, obtaining.Known film comprises microwave plasma CVD, heated filament (hotfilament) CVD, dc arc jet plasma CVD etc.The diamond that obtains by these methods is usually expressed as electrical insulating property, but can make its conduction by impurity between film stage.Above-mentioned conductive diamond becomes the problem in semi-conductor and the research and development of electronic component application facet in the quite a long time, especially the vapor phase growth aspect of single-crystal diamond, but cause people extensive concern by the synthetic electroconductibility polycrystalline diamond of producing that has of gas phase recent years, because such polycrystalline diamond might be used as the water treatment electrode.

In order to handle a large amount of water, the diamond electrode that is used for water treatment is delivered at big electric current under the situation of large electrode and is used.Therefore, the efficient of handling for improving, importantly the resistance value at the diamond layer of electrode outermost surface is little.

The most general currently known methods that is used for the polycrystalline conductive diamond of water treatment electrode for production is doped with boron between film stage by microwave plasma CVD or heated filament CVD.

Doped with boron has many different currently known methodss between film stage, and following is some specific exampless.

Japanese Patent publication 2001-147211 discloses a kind of relating to and has been used for stable and high sensitivity and measures invention in the method for liquid uric acid level, and it is measured by using anodized diamond film electrode.Here, producing in the diamond thin process boron oxide (B by microwave plasma CVD ₂O ₃) be dissolved in acetone and the methanol mixture, use H ₂Gas is input to this solution in the device as carrier gas, thereby forms film.

Japanese Patent publication H9-13188 describes and relates to the diamond electrode that a kind of partial electrode at least is made up of effect of semiconducting diamond films, wherein diborane (the B that dilutes with hydrogen ₂H ₆) as raw gas, form diamond film by microwave plasma CVD.

Japanese Patent publication 2000-313982 relates to a kind of by form the electrode of diamond layer preparation on base material, and wherein doped with boron is by using trimethyl borate (B (OCH in diamond ₃) ₃) as being undertaken by the boron source in hot line CVD (heated filament CVD) the formation diamond layer, and boron content is 10～10,000ppm, preferred 10～2000ppm, more preferably 5～1000ppm.

At publication " Preprints of the 26 ^ThCommittee of Electrolytic ScienceTechnology, Committee of Soda Technology (Denkai GijutsuTouronkai-Soda Kougyou Gijutsu Touronkai Youshishu), pp.1-4 " in mention; when using the conductive diamond film on silicon substrate or niobium base material, form to carry out the electrolysis test; diamond electrode is because the corrosive wear of the separation of diamond film or base material and do not have enough wearing qualities, and this depends on solution or electrolytic condition.

For the main points of diamond electrode be can coated diamond high surface area, and for for the purpose of the electrical efficiency of electrode, the resistance value of diamond layer will reduce, and that is to say, a large amount of doped with boron.Equally, have in the process that forms on the base material of high surface area at conductive diamond film as electrode, film must have enough physics and chemical strength, and its adhesive power need afford to stand in the severe environment of high current density and high potential, corrosive environment such as electrolytic corrosion the separation that the stress that uses and produce causes between base material and conductive diamond.

In the method for using the borate doped trimethyl of filament CVD, show that a large amount of boron that mixes makes that electromotive force window (potential window) is littler, the quantity of therefore mixing can not increase.Mentioned identical situation in patent documentation 2, the document points out that a large amount of boron that mixes has influenced the quality of diamond film unfriendly and hindered the acquisition of diamond natural characteristics.Therefore, existing method is for by a large amount of boron being doped on the diamond electrode with high surface area and the conductive diamond of production low resistance stably and make the enough durable aspect of its base material all have many problems.

Patent documentation 1: Japanese Patent publication 2001-147211

Patent documentation 2: Japanese Patent publication H9-13188

Patent documentation 3: Japanese Patent publication 2000-313982

Non-patent literature 1:Preprints of the 26 ^ThCommittee of ElectrolyticScience Technology, Committee of Soda Technology (Denkai GijutsuTouronkai-Soda Kougyou Gijutsu Touronkai Youshishu)

Summary of the invention

The problem that quasi-solution of the present invention is determined

The object of the invention provides a kind of method that is used to produce conductive diamond, especially by improving peel strength in the electrolytic process fully and increase the method that the adhesive power between diamond film and the base material comes production high-performance, high durability electrode, and can be by increasing the diamond electrode that boron doping amount obtain to have enough low-resistance values by this method.

More particularly, the object of the invention provides a kind of method that is used for the production conductive diamond electrode, and the conductive diamond electrode that obtains by this method is provided.Utilize this method, the thermal expansivity of base material remains within the limited range, stress minimizing between diamond film and base material consequently obtains good adhesive power, by using insulating substrate to prevent that electrochemical membrane from separating from base material in electrolytic process, and by adding nitrogen, tungsten or wolfram varbide and doping agent simultaneously at the diamond production period as giving the boron of electroconductibility, thereby the crystallinity that has prevented the loss of diamond crystalline and utilized diamond to keep has stably obtained continuous and fine and close polycrystalline diamond film.

The device that addresses the above problem

The electrode of the present invention that its structure comprises base material and is coated in the diamond layer on this base material is characterised in that diamond-coated electrode comprises with diamond-coated base material, the concentration that wherein said diamond comprises boron and described boron is at least 10,000ppm and be no more than 100,000ppm.

Described boron doped diamond may comprise at least a in the group of being made up of nitrogen, tungsten and wolfram varbide.

Nitrogen concentration in described diamond is 1000ppm and be no more than 100,000ppm at least preferably.

Tungsten concentration in described diamond is 1000ppm and be no more than 100,000ppm at least preferably.

Nitrogen concentration in described diamond is 1000ppm and be no more than 100 at least preferably, 000ppm, and the preferred 1000ppm and be no more than 100,000ppm at least of tungsten concentration.

The preferred polycrystalline CVD of diamond diamond.

Described polycrystalline CVD diamond is preferably produced by heated filament CVD method.

The peak intensity of (111) direction that described diamond is measured at X-ray diffraction preferably is 3 times of peak intensity of (220) direction at least and is no more than 10 times, preferably is 1.2 times of peak intensity of (311) direction at least at the peak intensity of (220) direction.

The peak value halfwidth degree that is illustrated in (111) direction of described adamantine X-ray diffraction measurement is preferably 0.3～0.5.

1300～1380cm in described adamantine raman spectroscopy ^-1Average intensity preferably be no more than 1100～1700cm ^-13 times of average intensity.

This base material is preferably formed by isolator.

The thermal expansivity of described base material is preferably from 1.5 * 10 ^-6～8.0 * 10 ^-6

The thermal expansivity of described base material is more preferably from 2 * 10 ^-6～5.0 * 10 ^-6

Described base material preferably is made up of isolator, and thermal expansivity is 1.5 * 10 ^-6～8.0 * 10 ^-6

Described base material is preferably by making one of at least in oxide compound, nitride and the carbide.

Described base material preferably ceramic sintered compact.

Described base material is preferably by making one of at least in silicon nitride, silicon carbide, aluminium nitride, mullite and the trichroite.

Described base material is preferably by making one of at least in aluminum oxide, silicon carbide and the titanium dioxide.

Preferred 0.2～5.0 μ m of the surface roughness Ra on the surface that is coated with diamond of described base material.The formation and the processing that are coated with adamantine ceramic post sintering surface were preferably carried out before the ceramic sintered bodies sintering, and did not preferably carry out mechanical workout after sintering.

The formation and the processing that are coated with adamantine ceramic post sintering surface are preferably carried out after the ceramic sintered bodies sintering, and preferably heat-treat once more after sintering.

The preferred milling of described processing, sandblast or grinding.

The preferred milling of described processing.

Described adamantine thickness is at least 0.1 μ m and be no more than 20 μ m preferably.

Described adamantine particle diameter is at least 0.1 μ m and be no more than 5 μ m preferably.

Above-mentioned electrode with the diamond coating is used for the material by the electrochemical reaction decomposing solution.

Preferably use such method production conductive diamond electrode: in vacuum vessel, place and be filled with sample clamp and the container that comprises as the liquid of the boron of basal component and oxygen, tungsten filament is placed on the place near sample clamp, base material is placed on the sample clamp, vacuum vessel is evacuated, hydrogen is imported till obtaining predetermined pressure by the predetermined mix ratio with the gas that serves as carbon source then, carrier gas is input to from import and is filled with the container that comprises as the liquid of the boron of basal component and oxygen then, comprise that the vapour transmission outlet as the solution of the boron of basal component and oxygen is input in the vacuum vessel, make electric current flow through described tungsten filament to produce heat, regulate cooling efficiency by water cooling sample clamp or other similar approach, thereby make base material reach preset temperature, thereby on substrate surface, can deposit the diamond film of the boron that mixed at least, and wherein the tungsten filament diameter is at least 0.1mm and is no more than 0.5mm, interval between tungsten filament and the base material is at least 4mm and is no more than 10mm, gaseous tension is at least 0.6kPa and is no more than 7kPa, and filament temperature is at least 2100 ℃ and be no more than 2300 ℃.

The effect of invention

In the combined electrode that relates to a kind of conductive diamond film that is doped with boron that comprises base material and on this base material, form, utilize the present invention, be 1.5 * 10 preferably by thermal expansivity ^-6～8.0 * 10 ^-6The isolator base material and the doping of described boron be 10,000～100,000ppm can obtain to have enough low resistance, has good film adhesive power and the electrode with good ionogen peel strength between diamond film and base material.

Description of drawings

Figure 1 shows that the electrode structure example with the diamond coating of the present invention;

Figure 2 shows that the figure of the X-ray diffraction measuring result of diamond layer;

Figure 3 shows that the figure of the halfwidth degree of explaining X-ray diffraction; With

Figure 4 shows that the raman spectroscopy result of diamond layer.

Embodiment

Diamond is insulating material normally, but it can be by mixing impurity such as boron has electroconductibility.The method that is used to produce man-made diamond generally classifies as high temperature, high pressure method and gas-phase synthesizing method, and the latter is the diamond that CVD is generally used for obtaining high surface area.Plasma CVD, heated filament CVD, plasma jet CVD or the like are that the synthetic acquisition of gas phase of passing through that is well known has the method for the diamond film of high surface area.

In heated filament CVD, sample clamp is placed in the diamond vacuum vessel, near tungsten filament is placed on, base material is placed on the sample clamp, and vacuum vessel is evacuated, and hydrogen is imported till obtaining predetermined pressure by the predetermined mix ratio with the gas that serves as carbon source then, make electric current flow through tungsten filament afterwards to produce heat, regulate cooling efficiency by water cooling sample clamp or other these class methods, thereby make sample reach preset temperature, thereby diamond film can deposit on the sample surfaces.

When this method is used for obtaining conductive diamond, should doped with boron.As the method for doped with boron, have as boric acid being placed near the simple method sample and the filament, or the method by the input diborane gas.Yet the problem of using former approach is to be difficult to a large amount of boron that mixes when regulating quantity, and uses the problem of latter's method to relate to use obnoxious flavour, therefore requires special security measures.

The mode of a large amount of boron of stably mixing is to charge into the liquid that contains boron and oxygen (hereinafter to be referred as " B source container ") in container, and use this container as bubbler (bubbler) content is incorporated into the CVD container.The liquid that contains boron and oxygen in this case can be the product of dissolving boric acid in methyl alcohol and acetone soln, maybe can be trimethyl borate or triethyl borate.This method is adjusted within the B source container that is fit to temperature with entering into as the hydrogen of carrier gas or rare gas element such as argon gas bubbling, makes the evaporation of boron source in container, and this steam is input in the vacuum reaction container.After the evaporation, can be along the pipelining under meter, the flow of the mixed gas that this under meter can controlling packet boracic source.

The conductive diamond of doped with boron can obtain in this way.Yet, making under certain condition in this way, the product of a large amount of boron that mixed may become agraphitic carbon, wherein diamond lattic structure distortion.For example, be 10,000～100 at the numerical value of doped with boron, under the high density situation of 000ppm, diamond may become agraphitic carbon.Because in the film product section is diamond lattic structure and part can increase for some states of agraphitic carbon, and the diamond quality that obtains depends on working condition and changes, so sometimes can not stable acquisition conductive diamond.

The inventor finds can address this problem in diamond by adding nitrogen, tungsten or wolfram varbide.Do like this and can stablize the low resistance conductive diamond that obtains to be doped with a large amount of boron, and the control filming condition can make the quality reduction minimize in technology, therefore can obtain to preserve densification, the continuous film of unique diamond lattic structure.

Have high-quality and enough low-resistance diamond film in order to obtain in this way, preferably the amount of doped with boron is 10,000～100 in diamond film, 000ppm.Same preferred nitrogen doping is 1000～100,000ppm, and the tungsten doping is 1000～100,000ppm.Can be by above-mentioned amount doping nitrogen or tungsten, perhaps the both mixes.

The adulterated boron for the treatment of of lucky above-mentioned content of mixing can be realized by the boron amount that control between synthesis phase adds.The nitrogen of lucky above-mentioned content of mixing can keep very small amount of nitrogen and realizes by making in reaction vessel.If boron mixes according to above-mentioned given amount, as long as nitrogen is a small amount of, then nitrogen mixes nature according to above-mentioned given amount so.

Just mixing the tungsten that is doped of above-mentioned content can be by using tungsten as filament material, the distance of controlled temperature and adjusting and base material realizes in reaction process.Preferably filament temperature is 2100～2300 ℃ in reaction process, and base material temperature is 800～1100 ℃.Above mentioned tungsten can exist with the wolfram varbide form in film.In this case, the temperature by keeping base material is between 900 and 1100 ℃, and the part tungsten in the film will keep as wolfram varbide.

Preferred conductive diamond film is a polycrystalline, and the crystal in film all is a random orientation rather than all towards specific direction.If crystal is all towards specific direction, then the doping of boron, nitrogen or tungsten can be than great fluctuation process.More particularly, preferably be 3 times of peak intensity of (220) direction at least and be no more than 10 times at the diamond peak intensity of (111) direction during X-ray diffraction is measured, and preferably be 1.2 times of peak intensity of (311) direction at least at the peak intensity of (220) direction.Equally, the halfwidth degree at the peak of (111) direction was preferably 0.3～0.5 during the expression X-ray diffraction was measured.

When diamond layer is measured by Raman spectrometry, at 1300～1380cm ^-1Average intensity preferably at the most 3 times to 1100～1700cm ^-1Average intensity.Sharp-pointed diamond peak value is represented the less boron that mixes, and has in fact produced more high resistance.When mixing enough boron, can not sharp-pointed at the peak of Raman spectrum even diamond has good crystallinity yet.For example, herein " good crystallinity " to refer to diamond crystal be tangible front body (euhedral), or diamond kept adamantine feature, such as be chemically stable, have very high erosion resistance and have wide electromotive force window.

The thickness of described diamond layer is preferably 0.1～20 μ m, preferred 0.1～5 μ m of median size.If film is too thin, then some parts trends towards being interrupted, if but film is too thick, then there is bigger stress, will cause base material warpage, membrane sepn etc.If particle diameter is too little, then crystallinity tend to impaired, if but particle diameter is too big, then in continuous film, do not have the part of landfill to trend towards exposing.

Will be by the preferred electrical insulator of base material of conductive diamond film coating.The term isolator of Shi Yonging represents that resistivity is at least 10 herein ⁶Ω cm.

The thermal expansivity of this base material is preferably 1.5 * 10 ^-6～8.0 * 10 ^-6The mean value of thermal expansivity herein is 40～800 ℃.If thermal expansivity is lower than this scope, when base material unrelieved stress at draw direction when diamond-coated will appear in the film, if but coefficient surpasses this scope, on pressing direction, unrelieved stress will be arranged, and diamond film will break after film forming or at the electrolysis test period, separation etc.Better thermal expansivity is 2.0 * 10 ^-6～5.0 * 10 ^-6

The material of insulating substrate is preferably by making one of at least in oxide compound, nitride and the carbide.The material of described insulating substrate can be silicon nitride, silicon carbide, aluminium nitride, mullite or trichroite.This material also can be aluminum oxide, silicon-dioxide or titanium dioxide, can be electrical isolation and has 1.5 * 10 ^-6～8.0 * 10 ^-6Thermal expansivity.

Because the base material temperature in film process almost can reach near 1000 ℃, therefore the performance that requires usually for the base material that will form diamond film thereon can afford to stand thermal stresses between base material and the diamond film for this base material, and has high fusing point; That is, the thermal expansivity of base material should not differ too big with adamantine thermal expansivity.Base material also need be made by the almost indiffusible material of carbon wherein, and need almost can not be by the hydrogen etching.

When base material in the electrochemical reaction is used as electrode, in order to improve the peel strength that diamond film leaves base material, the preferred isolator of described base material.If base material conducts electricity, then because from the pin hole of diamond film, in the electrochemistry influence to base material such as the liquid of the slit infiltration of crystal boundary etc., diamond film will separate.

Because the character of stress generations that causes from a large amount of boron that mix etc., adhesion etc. and above-mentioned discussion, so select above-mentioned base material as the mixed base material of low resistance conductive diamond film of high density boron of formation thereon.

These base materials preferably have the coated diamond wanted and roughness Ra is the surface of 0.2～5.0 μ m.If base material is level and smooth and has low surface roughness, though so when use keep to common diamond film the base material of excellent adhesion is arranged the time, form in the present invention under the situation of the conductive diamond film that is doped with a large amount of boron and also can occur separating.Therefore, in order to obtain good adhesive power between base material and diamond film, the preferred substrates surface has above-mentioned roughness.

When ceramic sintered bodies when forming the base material of diamond film thereon, the formation and the processing that preferably are formed with the substrate surface of diamond film were thereon carried out before sintering, and did not carry out mechanical workout after sintering.By the processing after the sintering, stress can remain on the substrate surface, and this stress is one of factor that causes the adhesive power reduction between base material and the diamond film.After sintering, add man-hour, heat-treat once more after the preferred processing.This has removed above mentioned unrelieved stress and has eliminated the detrimentally affect that adhesive power reduces.

For the sintering not special restriction of method of processing ceramic substrate surface before, but preferred milling, sandblast or grinding.No matter working method is how, surfaceness can be controlled by selection condition, thus the adhesive power of control and diamond film.Though particularly ceramic surface is difficult to carry out milling after sintering, but the periodicity bump can be accurately carried out in the milling before the sintering on substrate surface, and it is can obtain to be difficult to the predetermined surface shape of acquisition, and effective especially for the adhesive power that improves with diamond film sometimes by other two kinds of methods.

Embodiment 1

The substrate of size shown in the table 1 and material is as base material, and its surface is cleaned then with the diamond powder scraping.Each of these base materials all is placed in the synthesizer shown in the table 1, and compositing conducting diamond 1 on base material 2 as shown in Figure 1.

As show shown in the 1-1, synthesize the gaseous tension at 2.7kPa or 7kPa, the hydrogen flowing quantity of 5000sccm, the methane (CH of 0.5～2.0sccm ₄) carry out under the flow.Triethyl borate (B (OC ₂O ₅) ₃) as the boron source.Argon gas bubbles as carrier gas, and boron is 0.2～1.0% concentration supply with the atomic ratio with respect to carbon.The temperature of substrate that is to say that the temperature of base material is at 700～1000 ℃.

When synthesizer was heated filament CVD device (HFCVD), filament was made with tungsten and filament temperature is 2000～2200 ℃.When synthesizer was microwave plasma CVD device (MPCVD), microwave frequency was that 2.45GHz and microwave are output as 5kw.Generated time is 4 hours, and is changed as the concentration of showing methane flow shown in the 1-1 and diborane gas, to change adamantine thickness.

After diamond is synthetic, takes out and observe under 100 times stereoscopic microscope from device, whether the diamond separation has taken place in detection and whether diamond is synthetic on whole base material.As a result, do not have isolating sample and do not have the sample of composite part not in table 1-1, to represent with zero, otherwise with * represent.

Each gained diamond film all carries out outward appearance detection, measuring resistance, carries out the SEM observation and carries out simple electrolysis test as electrochemical evaluation.The electrolysis test condition is as follows: at first, use sulphuric acid soln, the 0.1A/cm of 0.1M ²Current density and two electrodes (electrolysis test 1) use the electrode of same-type to test 2 hours; After this, use sulphuric acid soln at 1.0A/cm ²Current density under (electrolysis test 2) tested about 10 hours.The result is table 1 illustrate.

[table 1-1]

Sample number into spectrum	Substrate material	Structure	Substrate sizes	Base material electroconductibility	Film	Diamond film thickness	Particle diameter	Separate after the film forming	Stereoscopic microscope evaluation after the electrolysis test 1	Separation after the electrolysis test 1	Separation after the electrolysis test 2
Sample number into spectrum	Substrate material	Structure	Substrate sizes	Base material electroconductibility	Film	Diamond film thickness	Particle diameter	Separate after the film forming		Separation after the electrolysis test 1	Separation after the electrolysis test 2	1-1	SiO ₂	Unformed	50×50×2	＞10 ¹⁴	MP	2.3	0.32	○	○	○	×
1-2	Si ₃N ₄	Polycrystalline	50×50×2	＞10 ¹⁴	HF	5.2	0.76	○	○	○	○	1-1	SiO ₂	Unformed	50×50×2	＞10 ¹⁴	MP	2.3	0.32	○	○	○	×
1-2	Si ₃N ₄	Polycrystalline	50×50×2	＞10 ¹⁴	HF	5.2	0.76	○	○	○	○	1-3	SiC	Polycrystalline	50×50×2	10 ⁸	HF	9.2	1.1	○	○	○	○
1-4	Si ₃N ₄	Polycrystalline	50×50×2	＞10 ¹⁴	HF	4.1	0.65	○	○	○	○	1-3	SiC	Polycrystalline	50×50×2	10 ⁸	HF	9.2	1.1	○	○	○	○
1-4	Si ₃N ₄	Polycrystalline	50×50×2	＞10 ¹⁴	HF	4.1	0.65	○	○	○	○	1-5	AlN	Polycrystalline	50×50×2	＞10 ¹⁴	HF	3.6	0.52	○	○	○	○
1-6	Al ₂O ₃	Polycrystalline	50×50×2	＞10 ¹⁴	HF	1.2	0.11	○	○	○	×	1-5	AlN	Polycrystalline	50×50×2	＞10 ¹⁴	HF	3.6	0.52	○	○	○	○
1-6	Al ₂O ₃	Polycrystalline	50×50×2	＞10 ¹⁴	HF	1.2	0.11	○	○	○	×	1-7	AlN	Monocrystalline	10×10×3	＞10 ¹⁴	MP	6.5	0.59	○	○	○	×
1-8	SiO ₂	Monocrystalline	10×10×3	＞10 ¹⁴	HF	19.3	1.87	○	○	○	×	1-7	AlN	Monocrystalline	10×10×3	＞10 ¹⁴	MP	6.5	0.59	○	○	○	×
1-8	SiO ₂	Monocrystalline	10×10×3	＞10 ¹⁴	HF	19.3	1.87	○	○	○	×	1-9	SiC	Monocrystalline	10×10×3	10 ⁸	MP	4.2	0.39	○	○	○	×
1-10	SiO ₂	Unformed	500×250×3	＞10 ¹⁴	HF	3.6	0.31	○	○	○	×	1-9	SiC	Monocrystalline	10×10×3	10 ⁸	MP	4.2	0.39	○	○	○	×

Sample number into spectrum	Substrate material	Structure	Substrate sizes	Base material electroconductibility	Film	Diamond film thickness	Particle diameter	Separate after the film forming	Stereoscopic microscope evaluation after the electrolysis test 1	Separation after the electrolysis test 1	Separation after the electrolysis test 2
Sample number into spectrum	Substrate material	Structure	Substrate sizes	Base material electroconductibility	Film	Diamond film thickness	Particle diameter	Separate after the film forming		Separation after the electrolysis test 1	Separation after the electrolysis test 2	1-11	Si	Polycrystalline	50×50×2	10 ²	HF	3.1	0.39	○	×	×	-
1-12	Si	Monocrystalline	50×50×2	10 ^-1	HF	2.9	0.23	○	×	×	-	1-11	Si	Polycrystalline	50×50×2	10 ²	HF	3.1	0.39	○	×	×	-
1-12	Si	Monocrystalline	50×50×2	10 ^-1	HF	2.9	0.23	○	×	×	-	1-13	Mo	Monocrystalline	50×50×2	10 ^-8	HF	4.1	0.46	○	×	×	-
1-14	SiO ₂	Unformed	10×10×1	＞10 ¹⁴	HF	21.2	2.3	×	-	-	-	1-13	Mo	Monocrystalline	50×50×2	10 ^-8	HF	4.1	0.46	○	×	×	-
1-14	SiO ₂	Unformed	10×10×1	＞10 ¹⁴	HF	21.2	2.3	×	-	-	-	1-15	SiO ₂	Unformed	10×10×1	＞10 ¹⁴	HF	19.1	1.8	○	×	×	-
1-16	SiO ₂	Unformed	10×10×1	＞10 ¹⁴	MP	0.14	0.019	○	×	×	-	1-15	SiO ₂	Unformed	10×10×1	＞10 ¹⁴	HF	19.1	1.8	○	×	×	-
1-16	SiO ₂	Unformed	10×10×1	＞10 ¹⁴	MP	0.14	0.019	○	×	×	-	1-17	SiO ₂	Unformed	10×10×1	＞10 ¹⁴	MP	0.06	0.007	×	-	-	-
1-18	Si ₃N ₄	Polycrystalline	50×50×2	＞10 ¹⁴	HF	18.9	4.8	○	○	○	○	1-17	SiO ₂	Unformed	10×10×1	＞10 ¹⁴	MP	0.06	0.007	×	-	-	-
1-18	Si ₃N ₄	Polycrystalline	50×50×2	＞10 ¹⁴	HF	18.9	4.8	○	○	○	○	1-19	Si ₃N ₄	Polycrystalline	50×50×2	＞10 ¹⁴	HF	14.9	5.2	○	×	○	×
1-20	Si ₃N ₄	Polycrystalline	50×50×2	＞10 ¹⁴	HF	20.8	4.1	○	×	○	×	1-19	Si ₃N ₄	Polycrystalline	50×50×2	＞10 ¹⁴	HF	14.9	5.2	○	×	○	×

[table 1-2]

The sample number into spectrum sign indicating number	B content	W content	N content	Resistance (* 10 ^-3)	The electromotive force window	Outward appearance	Filament diameter	Filament temperature	Pressure (kPa)	Distance from base material	The Ra of base material
The sample number into spectrum sign indicating number	B content	W content	N content	Resistance (* 10 ^-3)	The electromotive force window	Outward appearance	Filament diameter	Filament temperature	Pressure (kPa)	Distance from base material	The Ra of base material	1-1	1800	-	-	11.3	3.1	-	-	-	7	-	1.7
1-2	16,000	2100	1900	4.7	3.1	Diamond front body	0.25Φ	2150	2.7	10	0.3	1-1	1800	-	-	11.3	3.1	-	-	-	7	-	1.7
1-2	16,000	2100	1900	4.7	3.1	Diamond front body	0.25Φ	2150	2.7	10	0.3	1-3	36,000	14,000	5300	2.9	3.1	Diamond front body	0.25Φ	2150	2.7	10	1.9
1-4	24,000	600	1800	4.3	3.1	Diamond front body	0.25Φ	2150	2.7	10	2.3	1-3	36,000	14,000	5300	2.9	3.1	Diamond front body	0.25Φ	2150	2.7	10	1.9
1-4	24,000	600	1800	4.3	3.1	Diamond front body	0.25Φ	2150	2.7	10	2.3	1-5	35,000	1700	800	4.5	3.1	Diamond front body	0.25Φ	2150	2.7	10	2.9
1-6	29,000	17,000	2800	3.1	3.1	Diamond front body	0.25Φ	2150	2.7	10	1.1	1-5	35,000	1700	800	4.5	3.1	Diamond front body	0.25Φ	2150	2.7	10	2.9
1-6	29,000	17,000	2800	3.1	3.1	Diamond front body	0.25Φ	2150	2.7	10	1.1	1-7	42,000	-	-	3.8	2.4	Unformed	-	-	7	-	1.2
1-8	31,000	2800	2900	9.7	-	Diamond front body	0.25Φ	2150	2.7	10	1.5	1-7	42,000	-	-	3.8	2.4	Unformed	-	-	7	-	1.2
1-8	31,000	2800	2900	9.7	-	Diamond front body	0.25Φ	2150	2.7	10	1.5	1-9	1600	-	-	240	3.1	Diamond front body	-	-	7	-	1.9
1-10	18,000	1600	2800	4.1	3.1	Diamond front body	0.25Φ	2150	2.7	10	1.1	1-9	1600	-	-	240	3.1	Diamond front body	-	-	7	-	1.9

Sample number into spectrum	B content	W content	N content	Resistance (* 10 ^-3)	The electromotive force window	Outward appearance	Filament diameter	Filament temperature	Pressure (kPa)	Distance from base material	The Ra of base material
Sample number into spectrum	B content	W content	N content	Resistance (* 10 ^-3)	The electromotive force window	Outward appearance	Filament diameter	Filament temperature	Pressure (kPa)	Distance from base material	The Ra of base material	1-11	46,000	6100	2700	2.9	3.1	Diamond front body	0.25Φ	2150	2.7	10	0.5
1-12	39,000	2700	1600	3.3	3.1	Diamond front body	0.25Φ	2150	2.7	10	0.7	1-11	46,000	6100	2700	2.9	3.1	Diamond front body	0.25Φ	2150	2.7	10	0.5
1-12	39,000	2700	1600	3.3	3.1	Diamond front body	0.25Φ	2150	2.7	10	0.7	1-13	68,000	3900	4200	3.7	3.1	Diamond front body	0.25Φ	2150	2.7	10	0.9
1-14	18,000	6700	8100	2.1	-	Film forming is poor	0.25Φ	2150	2.7	10	1.2	1-13	68,000	3900	4200	3.7	3.1	Diamond front body	0.25Φ	2150	2.7	10	0.9
1-14	18,000	6700	8100	2.1	-	Film forming is poor	0.25Φ	2150	2.7	10	1.2	1-15	29,000	2900	1600	2.9	3.1	Diamond front body	0.25Φ	2150	2.7	10	1.4
1-16	1500	-	-	310	3.1	Diamond front body	-	-	7	-	0.9	1-15	29,000	2900	1600	2.9	3.1	Diamond front body	0.25Φ	2150	2.7	10	1.4
1-16	1500	-	-	310	3.1	Diamond front body	-	-	7	-	0.9	1-17	1300	-	-	290	-	Film forming is poor	-	-	7	-	1.3
1-18	16,000	2100	1800	3.4	3.1	Diamond front body	0.25Φ	2150	2.7	10	4.7	1-17	1300	-	-	290	-	Film forming is poor	-	-	7	-	1.3
1-18	16,000	2100	1800	3.4	3.1	Diamond front body	0.25Φ	2150	2.7	10	4.7	1-19	13,000	2700	1500	4.2	3.1	Diamond front body	0.25Φ	2150	2.7	10	2.7
1-20	18,000	2400	1800	3.2	3.1	Diamond front body	0.25Φ	2150	2.7	10	2.1	1-19	13,000	2700	1500	4.2	3.1	Diamond front body	0.25Φ	2150	2.7	10	2.7

Separating appears in diamond when conductive diamond thickness surpasses 20 μ m as can be seen from Table 1.Equally, when conductive diamond thickness during less than 0.1 μ m conductive diamond can not on whole substrate surface, synthesize.In addition, when base material for having less than 10 ⁶During the conducting objects of the resistivity of Ω cm, in conductive diamond, can be observed micropore and after electrolysis test 1 is carried out diamond separate.

On the contrary, when base material for having at least 10 ⁶During the insulant of Ω cm resistivity, in conductive diamond, do not observe micropore, and at least immediately after electrolysis test 1 diamond do not separate.

Synthetic diamond polycrystalline normally in gas phase.For the preferred at least 0.01 μ m and be no more than 2 μ m of the diameter of diamond particles on outmost diamond surface.Whole surface will form and crystallinity reduces if size less than 0.01 μ m, will be difficult to spread all over, as when film is too thin.But greater than 2 μ m, micropore and crack can be expanded between diamond particles as fruit granule, cause separation subsequently.Separation and crack will occur.Can be by controlling adamantine nucleation density by the pre-treatment of the concentration of film forming, methane or other carbonaceous gas or by growth conditions subsequently, thus the particle diameter of control diamond particles.

Embodiment 2

The various types of table shown in the 2-1 and the base material of machining state use diamond powder to carry out seeding in advance, afterwards heated filament CVD device are used under several different formation conditions that (sample number into spectrum 2-1～2-20) forms diamond film at each sample.The size of each base material is 60mm ², and thickness is 2mm.The thermal expansivity of each base material is the mean thermal expansion coefficients in 40～800 ℃.The gas of Shi Yonging is input in the device by argon gas is bubbled herein, and this bubbler is filled with H ₂, CH ₄And as the trimethyl borate [B (OC in boron source ₂H ₅) ₃].

Common conditions is the kind of gas; The H of 1000sccm ₂Flow; The CH of 20sccm ₄Ar+B (the OCH of flow and 5sccm ₃) ₃Flow; Use the tungsten filament of diameter as 0.2mm; 2200 ℃ filament temperature and base material-filament be spaced apart 5mm.Base material temperature is adjusted within 600～950 ℃ by the cooling efficiency of control sample clamp.

In addition, use diamond powder to carry out seeding in advance, afterwards heated filament CVD device is used under several different formation conditions that (sample number into spectrum 2-21～2-32) forms diamond film at each sample at the various types of table shown in the 2-2 and the base material of machining state.The size of each base material is 60mm ², and thickness is 2mm.The thermal expansivity of each base material is the mean thermal expansion coefficients in 40～800 ℃.As for the gas of being imported, use the hydrogen and the boric acid of the proper amt in the mixing solutions that is dissolved in methyl alcohol and acetone, hydrogen bubbles and enters into resulting liquid, and the gas of Chan Shenging is as carbon source and boron source like this.Control starting material solution makes that carbon and boron ratio are 100: 1 with atomic ratio measuring.Gaseous tension in film process is 3kPa.

Diameter be the tungsten filament of 0.4mm as filament, filament temperature is 2200～2300 ℃, and base material-filament be spaced apart 10mm.Cooling efficiency by the control sample clamp is adjusted to base material temperature within 600～950 ℃.

Each diamond film of Huo Deing all carries out visual inspection, measuring resistance, SEM and observes like this, and measures impurity concentration in the film with SIMS, and diamond film is carried out simple electrolysis test as electrochemical evaluation.The concentration of dopant here is that boron is 15,000～25, and 000ppm, tungsten are that 2000～3000ppm and nitrogen are 1000～2000ppm.The electrolysis test condition is as follows: at first, use sulphuric acid soln, the 0.1A/cm of 0.1M ²Current density and use the electrode of same-type to carry out test in about 2 hours for two electrodes (electrolysis test 1); After this, use sulphuric acid soln at 1.0A/cm ²Current density under (electrolysis test 2) carry out test in about 10 hours.The result is table 2 illustrate.

[table 2-1]

Sample number into spectrum	Substrate material	The coefficient of expansion (* 10 ^-6)	Film thickness (μ m)	Resistance (Ω cm)	Structure	Surface roughness Ra (μ m)	Working method	The film outward appearance	Resistance (10 ^-3Ω· cm)	SEM observes	Electrolysis test 1	Electrolysis test 2
Sample number into spectrum	Substrate material	The coefficient of expansion (* 10 ^-6)	Film thickness (μ m)	Resistance (Ω cm)	Structure	Surface roughness Ra (μ m)	Working method	The film outward appearance	Resistance (10 ^-3Ω· cm)	SEM observes	Electrolysis test 1	Electrolysis test 2	2-1	Si	3.8	3.6	＜10 ²	Monocrystalline	1.2E-03	Minute surface precision work	Well	8.7	Diamond front body	Do not separate	Separate fully
2-2	Si	3.8	4.1	＜10 ²	Polycrystalline	0.23	Cutting	Well	6.9	Diamond front body	Part is separated	Separate fully	2-1	Si	3.8	3.6	＜10 ²	Monocrystalline	1.2E-03	Minute surface precision work	Well	8.7	Diamond front body	Do not separate	Separate fully
2-2	Si	3.8	4.1	＜10 ²	Polycrystalline	0.23	Cutting	Well	6.9	Diamond front body	Part is separated	Separate fully	2-3	Mo	5.1	3.9	＜10 ^-5	Polycrystalline	0.08	Superimposed	Well	4.9	Diamond front body	Do not separate	Separate fully
2-4	Mo	5.1	5.1	＜10 ^-5	Monocrystalline	2.3	Superimposed	Well	5.9	Diamond front body	Do not separate	Separate fully	2-3	Mo	5.1	3.9	＜10 ^-5	Polycrystalline	0.08	Superimposed	Well	4.9	Diamond front body	Do not separate	Separate fully
2-4	Mo	5.1	5.1	＜10 ^-5	Monocrystalline	2.3	Superimposed	Well	5.9	Diamond front body	Do not separate	Separate fully	2-5	W	4.5	3.8	＜10 ^-5	Polycrystalline	1.3	Superimposed	Well	3.9	Diamond front body	Do not separate	Separate fully
2-6	W	4.5	5.6	＜10 ^-5	Polycrystalline	7.3	Milling	All film growths	3.9	Diamond front body	Part is separated	Separate fully	2-5	W	4.5	3.8	＜10 ^-5	Polycrystalline	1.3	Superimposed	Well	3.9	Diamond front body	Do not separate	Separate fully
2-6	W	4.5	5.6	＜10 ^-5	Polycrystalline	7.3	Milling	All film growths	3.9	Diamond front body	Part is separated	Separate fully	2-7	Nb	7.1	4.6	＜10 ^-5	Monocrystalline	0.11	Superimposed	Well	4.1	Diamond front body	Separate	-
2-8	Nb	7.1	4.1	＜10 ^-5	Monocrystalline	3.6	Sandblast	Well	5.6	Diamond front body	Do not separate	Separate fully	2-7	Nb	7.1	4.6	＜10 ^-5	Monocrystalline	0.11	Superimposed	Well	4.1	Diamond front body	Separate	-
2-8	Nb	7.1	4.1	＜10 ^-5	Monocrystalline	3.6	Sandblast	Well	5.6	Diamond front body	Do not separate	Separate fully	2-9	Quartzy	0.5	3.8	＞10 ¹⁴	Unformed	1.2	Sandblast	Well	18.9	Diamond front body	Do not separate	Separate fully
2-10	AlN	5.4	3.1	＞10 ¹⁴	Sintered compact	2.6	Sandblast behind the sintering	Well	16.2	Diamond front body	Do not separate	Do not separate	2-9	Quartzy	0.5	3.8	＞10 ¹⁴	Unformed	1.2	Sandblast	Well	18.9	Diamond front body	Do not separate	Separate fully

Sample number into spectrum	Substrate material	The coefficient of expansion (* 10 ^-6)	Film thickness (μ m)	Resistance (Ω cm)	Structure	Surface roughness Ra (μ m)	Working method	The film outward appearance	Resistance (10 ^-3Ω· cm)	SEM observes	Electrolysis test 1	Electrolysis test 2
Sample number into spectrum	Substrate material	The coefficient of expansion (* 10 ^-6)	Film thickness (μ m)	Resistance (Ω cm)	Structure	Surface roughness Ra (μ m)	Working method	The film outward appearance	Resistance (10 ^-3Ω· cm)	SEM observes	Electrolysis test 1	Electrolysis test 2	2-11	AlN	5.4	7.8	＞10 ¹⁴	Sintered compact	3.1	Milling just before the sintering	Well	16.5	Diamond front body	Do not separate	Do not separate
2-12	AlN	5.4	4.1	＞10 ¹⁴	Sintered compact	1.1	Grind behind the sintering	Well	18.8	Diamond front body	Very little separation	Part is separated	2-11	AlN	5.4	7.8	＞10 ¹⁴	Sintered compact	3.1	Milling just before the sintering	Well	16.5	Diamond front body	Do not separate	Do not separate
2-12	AlN	5.4	4.1	＞10 ¹⁴	Sintered compact	1.1	Grind behind the sintering	Well	18.8	Diamond front body	Very little separation	Part is separated	2-13	SiC	4.6	8.9	＞10 ⁶	Sintered compact	6.1	Sandblast behind the sintering	All film growths	17.9	Diamond front body	Part is separated	Part is separated
2-14	SiC	4.6	19.1	＞10 ⁶	Sintered compact	2.8	Sandblast before the sintering	Well	12.3	Diamond front body	Do not separate	Do not separate	2-13	SiC	4.6	8.9	＞10 ⁶	Sintered compact	6.1	Sandblast behind the sintering	All film growths	17.9	Diamond front body	Part is separated	Part is separated
2-14	SiC	4.6	19.1	＞10 ⁶	Sintered compact	2.8	Sandblast before the sintering	Well	12.3	Diamond front body	Do not separate	Do not separate	2-15	SiC	4.6	3.4	＞10 ⁶	Sintered compact	0.31	Superimposed behind the sintering	Well	11.9	Diamond front body	Do not separate	Do not separate
2-16	Si ₃N ₄	3.3	4.2	＞10 ¹⁴	Sintered compact	3.6	Milling just before the sintering	Well	12.3	Diamond front body	Do not separate	Do not separate	2-15	SiC	4.6	3.4	＞10 ⁶	Sintered compact	0.31	Superimposed behind the sintering	Well	11.9	Diamond front body	Do not separate	Do not separate
2-16	Si ₃N ₄	3.3	4.2	＞10 ¹⁴	Sintered compact	3.6	Milling just before the sintering	Well	12.3	Diamond front body	Do not separate	Do not separate	2-17	Si ₃N ₄	3.3	3.6	＞10 ¹⁴	Sintered compact	2.9	Sandblast behind the sintering	Well	11.8	Diamond front body	Do not separate	Do not separate
2-18	Si ₃N ₄	3.3	8.9	＞10 ¹⁴	Sintered compact	0.19	Superimposed behind the sintering	Well	13.1	Diamond front body	Part is separated	Part is separated	2-17	Si ₃N ₄	3.3	3.6	＞10 ¹⁴	Sintered compact	2.9	Sandblast behind the sintering	Well	11.8	Diamond front body	Do not separate	Do not separate
2-18	Si ₃N ₄	3.3	8.9	＞10 ¹⁴	Sintered compact	0.19	Superimposed behind the sintering	Well	13.1	Diamond front body	Part is separated	Part is separated	2-19	Fe	13.5	3.4		Metallic Solids	0.35		Film is growth not	-	-	-	-
2-20	SUS		3.1		Metallic Solids	0.39		Separate	-	-	-	-	2-19	Fe	13.5	3.4		Metallic Solids	0.35		Film is growth not	-	-	-	-

[table 2-2]

Sample number into spectrum	Substrate material	The coefficient of expansion	Film thickness (μ m)	Resistance (Ω c m)	Structure	Surface roughness Ra (μ m)	Working method	The film outward appearance	Resistance (10 ^-3Ω ·cm)	SEM observes	Electrolysis test 1	Electrolysis test 2
Sample number into spectrum	Substrate material	The coefficient of expansion	Film thickness (μ m)	Resistance (Ω c m)	Structure	Surface roughness Ra (μ m)	Working method	The film outward appearance	Resistance (10 ^-3Ω ·cm)	SEM observes	Electrolysis test 1	Electrolysis test 2	2-21	Quartzy	0.5	9.1	＞10 ¹⁴	Unformed	2.5	Sandblast	Well	16.5	Diamond front body	Separate	-
2-22	Mullite	4.8	4.3	＞10 ¹⁴	Sintered compact	1.6	Sintering	Well	12.1	Diamond front body	Do not separate	Do not separate	2-21	Quartzy	0.5	9.1	＞10 ¹⁴	Unformed	2.5	Sandblast	Well	16.5	Diamond front body	Separate	-
2-22	Mullite	4.8	4.3	＞10 ¹⁴	Sintered compact	1.6	Sintering	Well	12.1	Diamond front body	Do not separate	Do not separate	2-23	Trichroite	1.4	3.9	＞10 ¹⁴	Sintered compact	0.9	Grind behind the sintering	Well	16.1	Diamond front body	Part is separated	Separate fully
2-24	Trichroite	1.7	4	＞10 ¹⁴	Sintered compact	1.1	Grind behind the sintering	Well	17.1	Diamond front body	Do not separate	Very little separation	2-23	Trichroite	1.4	3.9	＞10 ¹⁴	Sintered compact	0.9	Grind behind the sintering	Well	16.1	Diamond front body	Part is separated	Separate fully
2-24	Trichroite	1.7	4	＞10 ¹⁴	Sintered compact	1.1	Grind behind the sintering	Well	17.1	Diamond front body	Do not separate	Very little separation	2-25	Trichroite	2.1	3.7	＞10 ¹⁴	Sintered compact	1	Grind behind the sintering	Well	16.5	Diamond front body	Do not separate	Do not separate
2-26	Steatite	8.1	5.1	＞10 ¹⁴	Sintered compact	0.7	Grind behind the sintering	Well	13.9	Diamond front body	Separate	-	2-25	Trichroite	2.1	3.7	＞10 ¹⁴	Sintered compact	1	Grind behind the sintering	Well	16.5	Diamond front body	Do not separate	Do not separate
2-26	Steatite	8.1	5.1	＞10 ¹⁴	Sintered compact	0.7	Grind behind the sintering	Well	13.9	Diamond front body	Separate	-	2-27	Aluminum oxide	8.2	3.6	＞10 ¹⁴	Sintered compact	0.8	Grind behind the sintering	Well	11.9	Diamond front body	Separate	-

40～800℃

Mean value

Sample number into spectrum	Substrate material	The coefficient of expansion	Film thickness (μ m)	Resistance (Ω cm)	Structure	Surface roughness Ra (μ m)	Working method	The film outward appearance	Resistance (10 ^-3Ω ·cm)	SEM observes	Electrolysis test 1	Electrolysis test 2
Sample number into spectrum	Substrate material	The coefficient of expansion	Film thickness (μ m)	Resistance (Ω cm)	Structure	Surface roughness Ra (μ m)	Working method	The film outward appearance	Resistance (10 ^-3Ω ·cm)	SEM observes	Electrolysis test 1	Electrolysis test 2	2-28	Alumina silica	7.8	4.2	＞10 ¹⁴	Sintered compact	2.7	Sintering	Well	14.6	Diamond front body	Do not separate	Very little separation
2-29	Alumina silica titanium dioxide	7.7	3.9	＞10 ¹⁴	Sintered compact	2.4	Sintering	Well	12.8	Diamond front body	Do not separate	Very little separation	2-28	Alumina silica	7.8	4.2	＞10 ¹⁴	Sintered compact	2.7	Sintering	Well	14.6	Diamond front body	Do not separate	Very little separation
2-29	Alumina silica titanium dioxide	7.7	3.9	＞10 ¹⁴	Sintered compact	2.4	Sintering	Well	12.8	Diamond front body	Do not separate	Very little separation	2-30	Aluminum oxide	7.5	5.1	＞10 ¹⁴	Sintered compact	1.3	Grind behind the sintering	Well	11.9	Diamond front body	Do not separate	Very little separation
2-31	SiC	4.6	3.8	＜10 ³	Sintered compact	1.1	Grind behind the sintering	Well	16.1	Diamond front body	Do not separate	Separate fully	2-30	Aluminum oxide	7.5	5.1	＞10 ¹⁴	Sintered compact	1.3	Grind behind the sintering	Well	11.9	Diamond front body	Do not separate	Very little separation
2-31	SiC	4.6	3.8	＜10 ³	Sintered compact	1.1	Grind behind the sintering	Well	16.1	Diamond front body	Do not separate	Separate fully	2-32	SiC	4.6	3.9	＜10 ^-1	Sintered compact	1.4	Grind behind the sintering	Well	15.3	Diamond front body	Do not separate	Separate fully

40～800℃

Mean value

As can be seen from Table 2 when surface roughness Ra 0.2～5.0 the time, forming good diamond film on Si, Mo, tungsten and the Nb base material and the separation of diamond film in electrolysis test 1 subsequently, do not occurring.Simultaneously, when surfaceness is outside this scope, occur separating, and all occur separating under each situation in electrolysis test 2.

When resistivity and the coefficient of expansion within above-mentioned scope and surfaceness when surpassing above-mentioned scope, in the electrolysis test, occur " part is separated ".Here " part is separated " mentioned comprises separation a little, and in fact also comprises the situation that does not almost have deterioration.In fact, for example, for sample number into spectrum 2-13, its surfaceness height, only very not coating of the film of small portion, and this part is extremely difficult identifies from separate part, therefore adopted the evaluation of " part is separated ", but the separate part that in fact illustrates there is not the sign of expansion.Therefore think that resistivity and thermal expansivity play significant feature aspect wearing quality.

From showing 2-1 and 2-2 as can be seen, when base material has greater than 10 ⁶The resistivity of Ω cm, surface roughness Ra occur separating in electrolysis test 1 or 2 in the scope of 0.2～5 μ m and thermal expansivity in 2.0～5.0 scope the time.When the thermal expansivity of sample 2.0～5.0 * 10 ^-6Outside but 1.5～8.0 * 10 ^-6Within the time, in electrolysis test 1, occur separating, although and slight separation has appearred in electrolysis test 2, do not occur separating fully.When the coefficient of expansion of sample 1.5～8.0 * 10 ^-6Scope outside the time, in electrolysis test 2, occurred separating fully.

Embodiment 3

Condition by base material (sample number into spectrum 2-11,12,14,16 and 17) among the use embodiment 2 and change electrolysis test is carried out another test.Electrolysis test was carried out 1000 hours under the following conditions: use the 0.1M metabisulfite solution, at 1.0A/cm ²Current density under, and two electrodes use the electrode of same types.The result is table 3 illustrate.

As can be seen from Table 3, for sample number into spectrum 2-12 ' and 2-17 ' with ceramic bases surface of processing after the sintering, though occur separating, in the embodiment 3 of severe condition more is set separation has appearred in the electrolysis test of embodiment 2.

On the contrary, even in the electrolysis test of embodiment 3, numbering 2-11 ', 2-14 ' with the surface that processed before sintering do not occur separating with 2-16 ' yet.

Equally, occurring under the condition of embodiment 3 separating and the base material identical and when this base material heat-treated 1 hour in 1000 ℃ vacuum after processing, even in implementing 3 electrolysis test, separation also occurs with 2-17 ' when using.

When to carrying out sandblast with the identical base material of numbering 2-1 and cut before sintering rather than during milling, the result is the result when carrying out milling much at one, but the repeatability of processing when carrying out milling is best.

[table 3]

Sample number into spectrum	Substrate material	Structure	Surface roughness Ra (μ m)	Working method	The electrolysis test
Sample number into spectrum	Substrate material	Structure	Surface roughness Ra (μ m)	Working method	The electrolysis test	2-11’	AlN	Sintered compact	3.1	Only milling before the sintering	Do not separate
2-12’	AlN	Sintered compact	1.1	Grind behind the sintering	Considerably less separation	2-11’	AlN	Sintered compact	3.1	Only milling before the sintering	Do not separate
2-12’	AlN	Sintered compact	1.1	Grind behind the sintering	Considerably less separation	2-14’	SiC	Sintered compact	2.6	Only milling before the sintering	Do not separate
2-16’	Si ₃N ₄	Sintered compact	3.6	Only milling before the sintering	Do not separate	2-14’	SiC	Sintered compact	2.6	Only milling before the sintering	Do not separate
2-16’	Si ₃N ₄	Sintered compact	3.6	Only milling before the sintering	Do not separate	2-17’	Si ₃N ₄	Sintered compact	2.9	Sandblast behind the sintering	Considerably less separation

Embodiment 4

Sample number into spectrum 1-2 in embodiment 1 carries out X-ray diffraction and raman spectroscopy.Fig. 2 and 3 shows the result of X-ray diffraction.From Fig. 2, find the ratio (I of the peak intensity (highly) of the peak intensity of (111) (highly) and (220) ₍₁₁₁₎/ I ₍₂₂₀₎) be 4.1.Ratio (the I of the peak intensity (highly) of peak intensity (220) (highly) and (311) ₍₂₂₀₎/ I ₍₃₁₀₎) be 1.5.Find that from Fig. 3 the halfwidth degree at (111) peak is (hereinafter to be referred as FWHM ₍₁₁₁₎) be 0.42.Fig. 3 shows the result of raman spectroscopy.From Fig. 4, find at 1300～1380cm ^-1Average intensity P1 with at 1100～1700cm ^-1The ratio (P1/P2) of average intensity P2 be 1.3.Measure in the same manner for sample number into spectrum 1-3 and 5.These results together with the result of the sample number into spectrum 2-21 in embodiment 2 shown in the table 4.

[table 4]

Sample number into spectrum	X-ray diffraction			Raman
Sample number into spectrum	X-ray diffraction					(I ₍₁₁₁₎/I ₍₂₂₀₎)	(I ₍₂₂₀₎/I ₍₃₁₀₎)	FWHM ₍₁₁₁₎
1-2	4.1	1.5	0.42			(I ₍₁₁₁₎/I ₍₂₂₀₎)	(I ₍₂₂₀₎/I ₍₃₁₀₎)	FWHM ₍₁₁₁₎	1.3
1-2	4.1	1.5	0.42	1-3	8.9	1.4	0.34	2.8	1.3
1-5	5.6	1.2	0.49	1-3	8.9	1.4	0.34	2.8	0.3
1-5	5.6	1.2	0.49	2-21	14.4	-	0.24	6.1	0.3

As shown in table 4, the peak intensity that the suitable sample number into spectrum 1-2,3 and 5 of boron content shows as (111) direction in X-ray diffraction is 3 times of peak intensity of (220) direction at least and is no more than 10 times, and is 1.2 times of peak intensity of (310) direction at least at the peak intensity of (220) direction.At the halfwidth degree of the peak value of (111) direction within 0.3～0.5.On the contrary,, surpass at (220) direction peak intensity 10 times, and if have the peak to discern in (310) direction at the peak intensity of (111) direction as for the sample number into spectrum 2-21 that contains small amount of boron.Halfwidth degree in (111) direction is at most 0.3.

In raman spectroscopy, the sample number into spectrum 1-2,3 and 5 that comprises appropriate level boron is at 1300～1380cm ^-1Average intensity less than at 1100～1700cm ^-13 times of average intensity, but then be not less than 3 times for sample number into spectrum 2-21.

Embodiment 5

With #60 aluminum oxide sand to carrying out sandblast, clean surface then at the substrate surface shown in the table 5.

On above-mentioned each base material, form the conductive diamond layer with heated filament CVD (HFCVD) or microwave CVD (MPCVD).

In synthetic with heated filament CVD, gaseous tension is 7kPa, and hydrogen flowing quantity is 3000sccm, and methane flow is within the scope of 0.5～5.0sccm.Diborane gas is as the boron source, and with respect to the flow concentration of its supply of methane in 0.2～1.0% scope.Base material temperature is between 700 and 1000 ℃.

Under the situation of microwave CVD, use identical pressure and throughput ratio, microwave frequency is 2.4GHz, and microwave is output as 5kW.

Therefore the diamond film that obtains each all to comprise concentration range be 10,000ppm～100, the boron of 000ppm.

As shown in table 5, film thickness and surfaceness change by changing methane flow and diborane gas flow." zero " is illustrated in the electrolysis and does not separate, and " * " represents that separation or base material crackle and electrolysis having occurred can not proceed.In electrolysis, diamond electrode is as negative electrode and anode in the container that is filled with the 1mol/L aqueous sulfuric acid.Electrode space 10mm fixes, and uses electric power to two electrodes.Electrolysis is at 1.0A/cm ²Electric current under carried out 100 hours.

[table 5]

Sample number	The film generation type	Substrate material	Film surfaceness (Rmax μ m)	Substrate surface roughness (Rmax μ m)	Film thickness (μ m)	Separate
Sample number	The film generation type	Substrate material	Film surfaceness (Rmax μ m)	Substrate surface roughness (Rmax μ m)	Film thickness (μ m)	Separate	5-1	HFCVD	SiC	8.4	7.6	3.8	○
5-2	HFCVD	SiC	0.01	3.2	5.1	×	5-1	HFCVD	SiC	8.4	7.6	3.8	○
5-2	HFCVD	SiC	0.01	3.2	5.1	×	5-3	HFCVD	SiC	0.09	5.3	9.1	×
5-4	HFCVD	SiC	20.2	8.2	10.2	×	5-3	HFCVD	SiC	0.09	5.3	9.1	×
5-4	HFCVD	SiC	20.2	8.2	10.2	×	5-5	HFCVD	SiC	30.2	6.4	5.7	×
5-6	HFCVD	SiC	7.6	0.03	8.6	×	5-5	HFCVD	SiC	30.2	6.4	5.7	×
5-6	HFCVD	SiC	7.6	0.03	8.6	×	5-7	HFCVD	SiC	6.8	0.49	3.5	×
5-8	HFCVD	SiC	8.2	10.2	7.5	×	5-7	HFCVD	SiC	6.8	0.49	3.5	×
5-8	HFCVD	SiC	8.2	10.2	7.5	×	5-9	HFCVD	SiC	7.2	19.2	4.8	×
5-10	HFCVD	SiC	3.6	4.9	0.001	×	5-9	HFCVD	SiC	7.2	19.2	4.8	×
5-10	HFCVD	SiC	3.6	4.9	0.001	×	5-11	HFCVD	SiC	9.7	6.8	0.011	×
5-12	HFCVD	SiC	8.4	5.9	20.1	×	5-11	HFCVD	SiC	9.7	6.8	0.011	×
5-12	HFCVD	SiC	8.4	5.9	20.1	×	5-13	HFCVD	SiC	5.3	9.1	30.2	×
5-14	HFCVD	SiC	0.48	18.9	0.008	×	5-13	HFCVD	SiC	5.3	9.1	30.2	×
5-14	HFCVD	SiC	0.48	18.9	0.008	×	5-15	HFCVD	Mo	4.5	7.8	5.6	○
5-16	HFCVD	W	7.2	4.6	8.1	○	5-15	HFCVD	Mo	4.5	7.8	5.6	○
5-16	HFCVD	W	7.2	4.6	8.1	○	5-17	HFCVD	Ti	4.2	7.3	2.3	○
5-18	HFCVD	Ta	8.2	3.2	4.3	○	5-17	HFCVD	Ti	4.2	7.3	2.3	○
5-18	HFCVD	Ta	8.2	3.2	4.3	○	5-19	HFCVD	Nb	9.2	5.4	3.2	○
5-20	HFCVD	Si	6.5	4.9	5.2	○	5-19	HFCVD	Nb	9.2	5.4	3.2	○
5-20	HFCVD	Si	6.5	4.9	5.2	○	5-21	HFCVD	Si ₃N ₄	7.2	5.3	4.6	○
5-22	HFCVD	AlN	5.9	4.6	3.8	○	5-21	HFCVD	Si ₃N ₄	7.2	5.3	4.6	○
5-22	HFCVD	AlN	5.9	4.6	3.8	○	5-23	HFCVD	Al ₂O ₃	5.4	3.2	2.8	○
5-25	MPCVD	SiC	4.3	6.2	5.8	○	5-23	HFCVD	Al ₂O ₃	5.4	3.2	2.8	○

As the maximum value Rmax of the surfaceness of the coated diamond layer of sample during, occur separating less than 0.1 μ m.Cutting sample and observation cross section show the slit in film.Similarly, when sample has the Rmax value that surpasses 20 μ m, occur separating also observing once more and find to have the slit to form.

Wherein the maximum surfaceness Rmax of base material surpasses the sample cutting of 10 μ m and observes cross section, shows that film does not stick in the deep notch, thereby has formed the slit.When separation has appearred during less than 0.5 μ m in the Rmax of sample.

When the diamond layer thickness of sample during less than 0.01 μ m, high resistance can cause producing a large amount of heat, and because separating appears with the thermal expansion of base material in diamond layer.The sample that thickness surpasses 20 μ m separates base material after film forming, and can not be used as electrode.When base material was made by silicon-dioxide, the separation of film took place during electrolysis.

Embodiment 6

Table 6 shows dissimilar base materials and carries out kind of brilliant a processing with diamond powder in advance, afterwards by using heated filament CVD device to form diamond film under various formation conditions.The gas of Shi Yonging is H herein ₂, CH ₄And as the trimethyl borate B (OCH in boron source ₃) ₃, and these gases are filled in the bubbler, and gas is incorporated in the device by bubbler bubbling argon gas.Total condition is the H of gaseous species, 1000sccm ₂The CH of flow, 20sccm ₄Ar+B (the OCH of flow and 5sccm ₃) ₃The gaseous tension of flow, 3kPa.Tungsten filament, the filament temperature that uses 0.2mm be 2200 and base material-filament be spaced apart 5mm.The temperature of base material is regulated between 600～950 ℃ by the cooling efficiency of control sample clamp.For each diamond film of such acquisition, measure its resistance, and measure the amount of adulterated boron and tungsten by secondary ion mass spectrometry (SIMS).Measure the electromotive force window by the SEM observation structure and as electrochemical evaluation.The result provides as follows.

[table 6]

Sample number into spectrum	Substrate material	The film outward appearance	B content	W content	Resistance (* 10 ^-3 Ω·cm )	SEM observes	The electromotive force window	Surfaceness Rmax (μ m)
Sample number into spectrum	Substrate material	The film outward appearance	B content	W content	Resistance (* 10 ^-3 Ω·cm )	SEM observes	The electromotive force window	Surfaceness Rmax (μ m)	6-1	Si	Well	24,000	2100	8.7	Diamond front body	3.1	0.52
6-2	Quartzy	Well	28,000	1900	5.9	Diamond front body	3.15	0.95	6-1	Si	Well	24,000	2100	8.7	Diamond front body	3.1	0.52
6-2	Quartzy	Well	28,000	1900	5.9	Diamond front body	3.15	0.95	6-3	SiC	Well	27,000	2400	11.2	Diamond front body	3.1	2.1
6-4	Si ₃N ₄	Well	19,000	1800	3.1	Diamond front body	3.2	2.8	6-3	SiC	Well	27,000	2400	11.2	Diamond front body	3.1	2.1
6-4	Si ₃N ₄	Well	19,000	1800	3.1	Diamond front body	3.2	2.8	6-5	AlN	Well	23,000	2000	6.9	Diamond front body	3.2	3.9
6-6	Mo	Well	20,000	2000	4.6	Diamond front body	3.2	6.8	6-5	AlN	Well	23,000	2000	6.9	Diamond front body	3.2	3.9
6-6	Mo	Well	20,000	2000	4.6	Diamond front body	3.2	6.8	6-7	W	Well	19,000	2050	5.9	Diamond front body	3.15	5.9
6-8	Nb	Well	21,000	1900	7.1	Diamond front body	3.1	9.1	6-7	W	Well	19,000	2050	5.9	Diamond front body	3.15	5.9
6-8	Nb	Well	21,000	1900	7.1	Diamond front body	3.1	9.1	6-9	Fe	Separate	-	-	-	- -	-	- -
6-10	SUS	Separate	-	-	-	-	-	-	6-9	Fe	Separate	-	-	-	- -	-	- -
6-10	SUS	Separate	-	-	-	-	-	-	6-11	Mo	Separate	-	-	-	-	-	0.081
6-12	Mo	Some film forming failures	-	-	-	Some film forming failures	-	11.3	6-11	Mo	Separate	-	-	-	-	-	0.081

The diamond film of sample 6-1～6-8 all shows good character as can be seen from the above results, and these samples all are to form film by heated filament CVD on the base material shown in the table 6 to obtain.

Embodiment 7

The conductive diamond film of sample 7-1～7-5 uses several different production methods and the substrate preparation shown in the table 7.Microwave plasma CVD and heated filament CVD are as the formation method of diamond film.Boron is as doping agent.Conduction polycrystalline diamond film is in that (sample 7-1～7-3) is measured as 75mm as base material ²Polysilicon on form.As a comparison, be measured as 5mm ²Monocrystalline Ib diamond on form conductive diamond epitaxial film (sample 7-4 and 7-5).

The common conditions that is used to form diamond film is that pressure is 2.66kPa, uses hydrogen, methane and conduct to import the Ar+ trimethyl borate of gas, and their ratio of mixture (volume ratio) is 1000: 20: (1～20).That is, the ratio of methane is the methane that the hydrogen of per 100 parts by volume has 2 parts by volume, and the volume of Ar+ trimethyl borate is 5～100 parts by volume with respect to methane.Trimethyl borate is to enter into the container that is filled with the liquid trimethyl borate by the bubbling argon gas to carry it into device.Base material temperature is 800 ℃.The condition of plasma CVD is under the energy grade of 5kw, and it is that tungsten filament, the filament temperature of 0.2mm is the 5mm that is spaced apart of 2200 ℃ and base material-filament that the condition of heated filament CVD is to use diameter.

Measure the doped with boron of each diamond film that obtains like this and the amount of tungsten.Use secondary ion mass spectrometry (SIMS) to carry out this measurement.Also measure the resistance of this diamond film.At sample 7-1～7-3 (75mm ²) in the base material size used be the electrode size of using in the electrolyzer that herein uses.At last, measure the electromotive force window.In measuring the electromotive force window, peripheral coating insulating resin, and the bare area of electrode is set at 50mm ²

[table 7]

Sample number into spectrum	Production method	Doping agent	Base material	B content (ppm)	W content (ppm)	Resistance (* 10 ^-3 Ω·cm )	The diamond film outward appearance	Electromotive force window (V)
Sample number into spectrum	Production method	Doping agent	Base material	B content (ppm)	W content (ppm)	Resistance (* 10 ^-3 Ω·cm )	The diamond film outward appearance	Electromotive force window (V)	7-1	Heated filament CVD	B	Si	25,000	3000	1.4	Fully evenly	3.2
7-2	Plasma CVD	B	Si	2000	＜DL	700	Film forming is poor on the turning	3.1	7-1	Heated filament CVD	B	Si	25,000	3000	1.4	Fully evenly	3.2
7-2	Plasma CVD	B	Si	2000	＜DL	700	Film forming is poor on the turning	3.1	7-3	Plasma CVD	B	Si	40,000	＜DL	12	Film forming is poor on the turning	2.4
7-4	Heated filament CVD	B	Single-crystal diamond Ib	4000	1200	89	Fully evenly	3.1	7-3	Plasma CVD	B	Si	40,000	＜DL	12	Film forming is poor on the turning	2.4
7-4	Heated filament CVD	B	Single-crystal diamond Ib	4000	1200	89	Fully evenly	3.1	7-5	Plasma CVD	B	Single-crystal diamond Ib	2000	＜DL	68	Fully evenly	3.1

[＜DL: be lower than limit of detection]

In the sample 7-1 that uses heated filament CVD doped with boron, the doping of boron and tungsten is big, and resistance is low, and the electromotive force window is wide.On the contrary, for the sample 7-2 and the 7-3 that use plasma CVD, the electromotive force window with the adulterated 7-2 of small amount of boron is wide, but it is narrower to have the electromotive force window of a large amount of adulterated 7-3.It is believed that reason is that adamantine crystalline structure is owing to a large amount of boron that mix are out of shape.

As for the membrane sample 7-1 that forms by heated filament CVD and use silicon substrate, film is formed uniformly on whole 75 square millimeters.But, in film forming sample 7-2 and 8-3, poor in corner's one-tenth film forming of base material by plasma CVD shape.For pass through the doped with boron epitaxy and film forming sample 7-4 of shape and 7-5 on single-crystal substrate, the electromotive force window is wide, and has kept the diamond proper property, still, and undoubted 75mm ²Big substrate sizes can not supply with, and resistance value is also than the height of 7-1.

Embodiment 8

Single crystalline Si (100) base material that has diameter and be 100mm, thickness and be 2mm and surfaceness Rmax and be 0.41 μ m uses diamond powder to carry out blade coating and handles, and this has produced trickle scratch from the teeth outwards and thus seeding has been carried out on the surface.Use filament CVD device and under several different filming condition shown in the table 8, on these base materials, form diamond film.The gas of Shi Yonging is H herein ₂, CH ₄, and as the trimethyl borate (B (OCH in boron source ₃) ₃), they are filled in the bubbler, and gas are input in the device through this bubbler by the argon gas bubbling.The common condition is the H of 1000sccm ₂The CH of flow, 20sccm ₄Ar+B (the OCH of flow and 5sccm ₃) ₃Flow.

Can obtain several samples by the interval that changes filming condition such as filament diameter and filament-base material.Base material temperature is regulated between 600～950 ℃ by the cooling efficiency of control sample clamp.Observe the structure of each diamond sample of acquisition like this by SEM, and measure electromotive force window as electrochemical evaluation.The result provides as follows.

[table 8]

Sample number into spectrum	Filament diameter (mm)	Filament temperature (℃)	Pressure (holder)	Filament-base material distance	B content (ppm)	W content (ppm)	SEM observes	Electromotive force window (V)	Resistance (* 10 ^-3Ω·cm)
Sample number into spectrum	Filament diameter (mm)	Filament temperature (℃)	Pressure (holder)	Filament-base material distance	B content (ppm)	W content (ppm)	SEM observes	Electromotive force window (V)	Resistance (* 10 ^-3Ω·cm)	8-1	0.1	2150	1.33	8	20,000	2000	Diamond front body	3.1	8.7
8-2	0.25	2200	2.0	6	10,000	8000	Diamond front body	3.15	5.9	8-1	0.1	2150	1.33	8	20,000	2000	Diamond front body	3.1	8.7
8-2	0.25	2200	2.0	6	10,000	8000	Diamond front body	3.15	5.9	8-3	0.4	2100	4.0	10	1000	100	Diamond front body	3.1	11.2
8-4	0.3	2300	2.66	4	100,000	100,000	Diamond front body	3.2	3.1	8-3	0.4	2100	4.0	10	1000	100	Diamond front body	3.1	11.2
8-4	0.3	2300	2.66	4	100,000	100,000	Diamond front body	3.2	3.1	8-5	0.5	2150	3.33	20	12,000	6000	Diamond front body	3.2	6.9
8-6	0.05	2100	3.33	20	Film is deposition not		-	-		8-5	0.5	2150	3.33	20	12,000	6000	Diamond front body	3.2	6.9
8-6	0.05	2100	3.33	20	Film is deposition not		-	-		8-7	0.3	2300	5.32	4	800	50	Diamond front body	3.15	290
8-8	0.4	2200	1.06	4	There is in a large number not connection portion		Diamond front body	2.7	160	8-7	0.3	2300	5.32	4	800	50	Diamond front body	3.15	290
8-8	0.4	2200	1.06	4	There is in a large number not connection portion		Diamond front body	2.7	160	8-9	0.25	2150	0.66	12	950	70	Diamond front body	3.1	260
8-10	0.3	2100	0.66	3	2000	300	Unformed	2.5	6.9	8-9	0.25	2150	0.66	12	950	70	Diamond front body	3.1	260
8-10	0.3	2100	0.66	3	2000	300	Unformed	2.5	6.9	8-11	0.3	2050	0.66	5	800	50	Diamond front body	3.1	320
8-12	0.3	2350	0.66	5	6000	500	Unformed	2.1	4.6	8-11	0.3	2050	0.66	5	800	50	Diamond front body	3.1	320

Embodiment 9

Use the diamond-coated electrode sample numbering 1-2 of usefulness of embodiment 1 to carry out the electrolysis test as the aqueous solution that electrode pair contains phenol.As a comparison, use platinum and lead dioxide electrode to carry out identical electrolysis test.As a result, when the electrode that uses with the diamond coating, the total organic carbon (TOC) in the aqueous solution drops to less than 10% being about in 30% time of required time of lead dioxide electrode.For platinum electrode, how long TOC can not reduce to about 30% regardless of the time.These results confirm that the diamond-coated electrode of usefulness of the present invention can decompose phenol effectively.

Commercial Application

As top detailed explanation, use the method for production conductive diamond electrode, can obtain to have enough low-resistance diamond electrodes by the amount that increases doped with boron. And, by the thermal coefficient of expansion of restriction base material or by using insulator as substrate material, may obtain the conductive diamond electrode that between diamond film and base material, has excellent adhesion and in electrolytic process, have the peel strength that substantially improves.

Claims

1. electrode with diamond coating, it comprises that wherein said diamond contains boron with diamond-coated base material, and the concentration of described boron is at least 10,00ppm and be no more than 100.000ppm.

2. the diamond-coated electrode of usefulness as claimed in claim 1, wherein the diamond of doped with boron comprises at least a in the group of being made up of nitrogen, tungsten and wolfram varbide.

3. the diamond-coated electrode of usefulness as claimed in claim 2, the nitrogen concentration that wherein is included in the described diamond is at least 1000ppm and is no more than 100,000ppm.

4. the diamond-coated electrode of usefulness as claimed in claim 2, the tungsten concentration that wherein is included in the described diamond is at least 1000ppm and is no more than 100,000ppm.

5. the diamond-coated electrode of usefulness as claimed in claim 2, the nitrogen concentration that wherein is included in the described diamond is at least 1000ppm and is no more than 100,000ppm, and tungsten concentration is at least 1000ppm and is no more than 100,000ppm.

6. as each described electrode with the diamond coating in the claim 1～5, wherein said diamond is a polycrystalline CVD diamond.

7. the electrode with the diamond coating as claimed in claim 6, wherein said polycrystalline CVD diamond is produced by heated filament CVD.

8. as each described electrode in the claim 1～7 with the diamond coating, wherein the described adamantine peak intensity on (111) direction that X-ray diffraction is measured is 3 times of peak intensity of (220) direction at least and is no more than 10 times, and is 1.2 times of peak intensity of (311) direction at least at the peak intensity of (220) direction.

9. as each described electrode in the claim 1～7, wherein in measuring, described diamond X-ray diffraction shows that the halfwidth degree at the peak of (111) direction is 0.3～0.5 with the diamond coating.

10. as the diamond-coated electrode of each described usefulness in the claim 1～9, wherein in described adamantine raman spectroscopy at 1300～1380cm ^-1Average intensity be no more than 1100～1700cm ^-13 times of average intensity.

11. as each described electrode with the diamond coating in the claim 1～10, wherein said base material is formed by isolator.

12. as the diamond-coated electrode of each described usefulness in the claim 1～11, the thermal expansivity of wherein said base material is 1.5 * 10 ^-6～8.0 * 10 ^-6

13. the electrode that usefulness as claimed in claim 12 is diamond-coated, the thermal expansivity of wherein said base material are 2 * 10 ^-6～5.0 * 10 ^-6

14. as the diamond-coated electrode of each described usefulness in the claim 1～10, wherein said base material is formed by isolator and thermal expansivity is 1.5 * 10 ^-6～8.0 * 10 ^-6

15. as each described electrode in the claim 1～14 with diamond coating, at least a the making in the group that wherein said base material is made up of oxide compound, nitride and carbide.

16. the electrode with the diamond coating described in claim 15, wherein said base material is a kind of ceramic sintered bodies.

17. at least a the making in the group that the electrode with diamond coating as claimed in claim 16, wherein said base material are made up of silicon nitride, silicon carbide, aluminium nitride, mullite and trichroite.

18. at least a the making in the group that the electrode with diamond coating as claimed in claim 16, wherein said base material are made up of aluminum oxide, silicon oxide and titanium dioxide.

19., will be 0.2～5.0 μ m wherein with the surface roughness Ra on the surface of diamond-coated described base material as the diamond-coated electrode of each described usefulness in the claim 1～18.

20., wherein will before the sintered ceramic sintered compact, carry out, and no longer carry out mechanical workout after the sintering with the formation and the processing of diamond-coated described ceramic post sintering surface as the diamond-coated electrode of each described usefulness in the claim 16～19.

21., wherein will after the sintered ceramic sintered compact, carry out, and after processing, heat-treat once more with the formation and the processing of diamond-coated described ceramic post sintering surface as the diamond-coated electrode of each described usefulness in the claim 16～19.

22., wherein saidly be processed as milling, sandblast or grinding as claim 20 or the diamond-coated electrode of 21 described usefulness.

23., wherein saidly be processed as milling as claim 20 or the diamond-coated electrode of 21 described usefulness.

24. as each described electrode with the diamond coating in the claim 1～23, wherein said adamantine thickness is at least 0.1 μ m and is no more than 20 μ m.

25. as each described electrode with the diamond coating in the claim 1～24, wherein said adamantine particle diameter is at least 0.1 μ m and is no more than 5 μ m.

26. an electrolysis process that uses electrode wherein uses as each described electrode that applies with diamond in the claim 1～25, utilizes the material in the electrochemical reaction decomposing solution.

27. method that is used to produce with diamond-coated electrode, wherein sample clamp and being filled with comprises that the container as the liquid of the boron of basal component and oxygen is placed in the vacuum vessel, tungsten filament is placed near the sample clamp, base material is placed on the sample clamp, vacuum vessel is evacuated, then hydrogen and the gas that serves as carbon source are imported up to obtaining predetermined pressure by predetermined ratio of mixture, then carrier gas is input to by import and is filled with in the container that comprises as the liquid of the boron of basal component and oxygen, comprise that the steam as the solution of the boron of basal component and oxygen is input in this vacuum vessel by outlet, make electric current flow through described filament to produce heat, by sample clamp water-cooled or another kind of these class methods are regulated cooling efficiency, thereby make described base material reach preset temperature, and deposition is doped with the diamond film of boron at least on substrate surface, and wherein the diameter of filament is at least 0.1mm and is no more than 0.5mm, interval between filament and the base material is at least 4mm and is no more than 10mm, gaseous tension is at least 0.6kPa and is no more than 7kPa, and filament temperature is at least 2100 ℃ and be no more than 2300 ℃.