Diamond-coated electrode and method for producing same

A diamond coating technology, applied in the direction of electrodes, electrolysis process, electrolysis components, etc., can solve the problems of small potential window, hindering the inherent characteristics of diamond, affecting the quality of diamond film, etc.

Inactive Publication Date: 2006-02-15
SUMITOMO ELECTRIC IND LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] In the method of doping trimethyl borate using filament CVD, it has been shown that doping a large amount of boron makes the potential window smaller, so the doping amount cannot be increased
The same situation is mentioned in Patent Document 2, which states that doping a large amount of boron adversely affects the quality of the diamond film and prevents the acquisition of the intrinsic properties of diamond
Therefore, existing methods have many problems both in stably producing low-resistance conductive diamond by doping a large amount of boron onto a diamond electrode with a large surface area, and in making its substrate durable enough.

Method used

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  • Diamond-coated electrode and method for producing same
  • Diamond-coated electrode and method for producing same
  • Diamond-coated electrode and method for producing same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0073] A substrate of the size and material shown in Table 1 was used as a substrate, and its surface was scraped with diamond powder and then cleaned. Each of these substrates was placed in the synthesis apparatus shown in Table 1, and as figure 1 The synthesis of conductive diamond 1 on a substrate 2 is shown.

[0074] As shown in Table 1-1, the gas pressure of 2.7kPa or 7kPa, the hydrogen flow rate of 5000sccm, and the methane (CH 4 ) flow rate. Triethyl borate (B(OC 2 o 5 ) 3 ) as a boron source. Argon gas was bubbled as a carrier gas, and boron was supplied at a concentration of 0.2 to 1.0% at an atomic ratio relative to carbon. The temperature of the base means that the temperature of the base material is 700-1000°C.

[0075] When the synthesis device is a hot-filament CVD device (HFCVD), the filament is made of tungsten and the temperature of the filament is 2000-2200°C. When the synthesis device is a microwave plasma CVD device (MPCVD), the microwave frequency ...

Embodiment 2

[0086] Substrates of various types and processing states shown in Table 2-1 were pre-seeded with diamond powder, after which a hot-wire CVD apparatus was used on each sample (Sample No. 2-1 ~2-20) Forming a diamond film. The size of each substrate is 60mm 2 , and the thickness is 2mm. The coefficient of thermal expansion of each base material is an average coefficient of thermal expansion within 40 to 800°C. The gas used here was input into the apparatus by bubbling argon with a bubbler filled with H 2 、CH 4 and trimethyl borate [B(OC 2 h 5 ) 3 ].

[0087] Common condition is the type of gas; 1000 sccm of H 2 flow; 20sccm CH 4 flow and 5sccm of Ar+B(OCH 3 ) 3 Flow rate; use of 0.2 mm diameter tungsten filament; filament temperature of 2200° C. and substrate-filament spacing of 5 mm. The substrate temperature is adjusted within 600-950°C by controlling the cooling efficiency of the sample holder.

[0088] In addition, substrates of various types and processing stat...

Embodiment 3

[0103] Another experiment was conducted by using the substrates in Example 2 (sample numbers 2-11, 12, 14, 16 and 17) and varying the conditions of the electrolysis test. The electrolysis test was carried out for 1000 hours under the following conditions: using 0.1M sodium sulfate solution, at 1.0A / cm 2 Under the current density, and the two electrodes use the same type of electrode. The results are shown in Table 3.

[0104] As can be seen from Table 3, for sample numbers 2-12' and 2-17' with ceramic substrate surfaces processed after sintering, although no separation occurred in the electrolytic test of Example 2, they were not separated in the implementation of more severe conditions. Separation occurred in Example 3.

[0105] In contrast, Nos. 2-11', 2-14' and 2-16' having surfaces processed before sintering did not show separation even in the electrolytic test of Example 3.

[0106] Also, when using the same base material as 2-17' that occurred separation under the con...

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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

Background technique [0001] Diamond obtained by vapor phase synthesis is considered as a method of obtaining polycrystalline diamond which has a relatively large surface area and is cheaper than natural diamond or artificial single crystal diamond obtained under ultra-high pressure, and is utilized in optical element applications and as heat sinks for electronic components and tools. Known film formation methods include microwave plasma CVD, hot filament CVD, DC arc spray plasma CVD, and the like. Diamonds obtained by these methods are generally electrically insulating, but can be made conductive by doping with impurities during film formation. The above-mentioned conductive diamond has been the subject of research and development in the application of semiconductors and electronic components for quite a long time, especially in the vapor phase growth of single crystal diamond, but in recent years, polycrystalline diamond with conductivity produced by gas phase synthesis has ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25B11/04
Inventor 关裕一郎泉健二今井贵浩
Owner SUMITOMO ELECTRIC IND LTD
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