JPS5834185A - Cathode for electrolysis - Google Patents

Abstract

PURPOSE:To provide an electrode for electrolysis which has a low hydrogen overvoltage, corrosion resistance to alkalis, and excellent retentivity of activity by providing a coating layer of nickel oxide by melt spraying on the surface of a conductive base body. CONSTITUTION:A base body which consists of Fe, Ni, Cu or their alloys, more preferably their alloys and is melt sprayed with Ni is used as a conductive base body. A coating layer of nickel oxide of >=20mu thicknes, more particularly about 50-200mu is provided by melt spraying on the surface of said base body. Here, powder of about 5-200mu is used for the nickel oxide which is a melt spraying source, and the melt spraying may be either of plasma spraying or fire spraying. The cathode having such melt sprayed coating of nickel oxide is better in hydrogen overvoltage and corrosion resistance than cathodes having melt sprayed coatings of nickel.

Description

【発明の詳細な説明】 本発ｆ１杜、アルカリ金属〕ｓ　ｇ　／ン化物水Ｓ＊中
アルカリ水溶ＩＩ［勢の電解に用いるＯｔｃ適し九電解
用陰極に関するものであシ、水素過電圧が低く、アルカ
リに対して耐食性があシ且つ活性持続性が優れた電解用
陰極を提供するものである。Detailed Description of the Invention The present invention relates to a cathode for electrolysis suitable for use in the electrolysis of alkali metals, alkali metals, s g / oxides in water S*, and a cathode for electrolysis. An object of the present invention is to provide a cathode for electrolysis that is resistant to corrosion against alkali and has excellent durability of activity.

従来、アルカリ金属）１０ゲン化物水ＩＩＩＩＩＩ１等
の電解に用いる陰極として社、鉄部が用いられてきたが
、これらは水素過電圧がＴｏｔＪ＞低くないので、電力
費の高騰に伴い、よシ低い水素過電圧の陰極の開発が必
費となう九。Conventionally, iron parts have been used as cathodes for electrolysis of alkali metal) 10-genide water III, etc., but since the hydrogen overvoltage of these is not lower than TotJ, with the rise in electricity costs, much lower hydrogen overvoltages have been used. 9. Development of an overvoltage cathode is necessary.

現在、水素過電圧の点から有力視されているのはｘｙケ
ルの多孔質被覆を有する陰極であ゛漬、多孔質ニッケル
被覆層の形成方法として、粉末状のニッケルを溶射によ
シ鉄系素地に四着させゐ方法（＃Ｍｌｉ５２−３２８５
２）、粒子状＝　ｙ　？　ｋ　ト粒子状アルミ１ウムの
１合糎車を湊射後アル々具つムを溶出する方法（特開４
５２−３４５８３）、及びニッケルとアルイエりムＯ相
互拡散合金層からアル建具りムを溶出してラネーニッケ
ルの表面層を形成する方法（特開昭５５−８１４８４）
＄がある。Currently, from the point of view of hydrogen overvoltage, the most promising method is to immerse the cathode with a porous coating of How to make it wear four (#Mli52-3285
2), Particulate = y? k A method of eluating aluminum after pouring a paste wheel containing 1 um of particulate aluminum (Unexamined Japanese Patent Publication No. 4)
52-34583), and a method for forming a surface layer of Raney nickel by eluting Al fitting rim from a nickel and Al rim O interdiffusion alloy layer (Japanese Patent Laid-Open No. 55-81484)
There is $.

しかしながら、溶射法によ多形成されるニッケルの被覆
層は、化学的耐食性の点で不十分であシ、電解槽の通電
停止時の電流変化に基づく陽分極によｎ＝ニッケル溶出
が起とｐやずいという問題が参った０本発明看は、金属
よシも化学的耐食性に優れ、且つ陽分極によ）影響を受
けない材質について、連射Ｏ可能性及び電気化学的特性
を検討し、水素過電圧及び耐食性ともに優れ九電解用陰
極を提供すべく研究した結果、溶射される材質として酸
化ニッケルを見い出し、本発明に到達したものである。However, the nickel coating layer formed by thermal spraying is insufficient in terms of chemical corrosion resistance, and n = nickel elution occurs due to anodic polarization due to current changes when the electrolytic cell is stopped energizing. The present inventor has investigated the possibility of continuous O radiation and the electrochemical properties of materials that have excellent chemical corrosion resistance, even metals, and are unaffected by anodic polarization. As a result of research to provide a cathode for electrolysis with excellent hydrogen overvoltage and corrosion resistance, nickel oxide was discovered as a material to be thermally sprayed, and the present invention was achieved.

本願第１の発明は、導電性基体表面上に、溶射によｐＨ
化ニッケルの被覆層を設けてなる電解用陰極に関する。The first invention of the present application provides pH adjustment by thermal spraying onto the surface of a conductive substrate.
The present invention relates to an electrolytic cathode provided with a coating layer of nickel oxide.

まえ、本願第２の発明は、導電性基体表面上に、溶射に
よ〉酸化ニッケルと犠牲金属との混合被覆層を設は九畿
、腋被榎層よル犠牲金属を溶出除去してなる電解用陰極
に関する。The second invention of the present application is to form a mixed coating layer of nickel oxide and sacrificial metal on the surface of a conductive substrate by thermal spraying, and to remove the sacrificial metal from the underarm layer by elution. Regarding cathodes for electrolysis.

導電性基体としては、鉄、ニッケル、鋼又れこれらの合
金等が用いられるが、酸化ニッケルの又は酸化ニッケル
を含む溶射層との結合力を高めるために鉄、ニッケル、
銅又はこれらの合金からなる基材上にニッケルを溶射し
たものを基体として用いるのが望ましい。Iron, nickel, steel, or alloys thereof are used as the conductive substrate, but iron, nickel,
It is desirable to use a substrate made of copper or an alloy thereof with nickel sprayed on it.

本願第１の発明においては、導電性基体表面上に、溶射
によシ酸化ニッケルの被覆層を設ける。In the first invention of the present application, a coating layer of nickel silica is provided on the surface of the conductive substrate by thermal spraying.

酸化ニッケルは５〜２００μ程度の粉末を使用する。溶
射は、プラズマ溶射、火炎溶射のいずれでもよく、溶射
によ多形成される酸化ニッケルの被覆層の厚さは２０，
４以上、好ましくは５０〜２００Ｐである。Powder of nickel oxide with a size of about 5 to 200 microns is used. Thermal spraying may be either plasma spraying or flame spraying, and the thickness of the nickel oxide coating layer formed by thermal spraying is 20 mm.
4 or more, preferably 50 to 200P.

本願第２の発明においては、導電性基体表面上に、溶射
によシ酸化ニッケルと犠牲金属との混合被覆層を般社た
後、諌被覆層よシ犠牲金属を溶出除去する。In the second aspect of the present invention, a mixed coating layer of nickel oxide and sacrificial metal is formed on the surface of the conductive substrate by thermal spraying, and then the sacrificial metal is eluted and removed from the coating layer.

犠牲金属としては、アルミニウム、”亜鉛、スズ等であ
り、このうち特に好ましい犠牲金属はアルミニウムであ
る。Examples of the sacrificial metal include aluminum, zinc, tin, etc. Among these, the particularly preferred sacrificial metal is aluminum.

酸化ニッケルと犠牲金属紘各々５〜２００Ｐ程度の粉末
を使用し、あらかじめ混合したものを溶射してもよいし
、また溶射ガンを２個以上用意し、酸化ニッケルと犠牲
金属とを別々のガンから同時に溶射してもよい。You can spray the nickel oxide and the sacrificial metal using powders of about 5 to 200 P each, mixed in advance, or prepare two or more thermal spray guns and spray the nickel oxide and the sacrificial metal from separate guns. It may be thermally sprayed at the same time.

酸化ニッケル粉末と犠牲金属粉末との割合は、陰極の水
素過電圧と耐久性の両者の兼ね合いから、体積百分率で
酸化ニッケル粉末５０〜９０％、犠牲金属５０〜１０１
ＪＩからなる範囲が好ましく、特に好ましくは酸化ニッ
ケル粉末６０〜７０−１犠牲金属４０〜５０−の範囲で
ある。犠牲金属が１０−以下で社、犠牲金属の滲出によ
る水素過電圧低下の効果がなく、犠牲金属が５０−以上
では耐久性が劣るようになる。尚、酸化ニッケル粉末の
一部を具ツケル粉末で置きかえることもできる。The ratio of the nickel oxide powder and the sacrificial metal powder is determined by volume percentages of 50 to 90% of the nickel oxide powder and 50 to 10% of the sacrificial metal, considering the balance between hydrogen overvoltage and durability of the cathode.
The range consisting of JI is preferred, and the range of nickel oxide powder from 60 to 70 -1 and sacrificial metal from 40 to 50 - is particularly preferred. When the sacrificial metal is less than 10, there is no effect of reducing the hydrogen overvoltage due to leaching of the sacrificial metal, and when the sacrificial metal is more than 50, the durability becomes poor. Incidentally, a part of the nickel oxide powder can also be replaced with nickel powder.

溶射はプラズマ溶射、火炎溶射のいずれを用いることも
でき、溶射によ多形成される被覆層の厚さはｓａｐ以上
、好ましくａ５０〜３００ｐである。Thermal spraying can be either plasma spraying or flame spraying, and the thickness of the coating layer formed by thermal spraying is at least SAP, preferably from A50 to 300P.

溶射後、犠牲金属の拡散を良くするためには、６０〜７
０℃で１〜３時間加熱処理するのが望ましい。After thermal spraying, in order to improve the diffusion of the sacrificial metal, 60 to 7
It is desirable that the heat treatment be carried out at 0°C for 1 to 3 hours.

上記のようにして、酸化ニッケルと犠牲金属との混合被
覆層を設けた後、被覆層中よシ犠牲金属を溶出除去する
。仁の溶出は力七イソーダ等のアルカリ中に浸漬するこ
とにより行う、溶出の条件は、被覆層中の犠牲金属の種
類、成分量によっても異なるが、はじめ５重量−１ｉ度
の低鎖度カセイソーダ涛液中に一昼夜浸漬後、２０〜３
０重量−の高濃度カセイソーダ溶液中に数時間浸漬する
方法が被覆に耐久性を持たせる上で望ましい。After providing the mixed coating layer of nickel oxide and sacrificial metal as described above, the sacrificial metal is eluted and removed from the coating layer. The elution of the seeds is carried out by immersing them in an alkali such as sodium chloride soda. The elution conditions vary depending on the type and content of the sacrificial metal in the coating layer, but the elution conditions are initially 5 weight - 1 i degrees of low chain caustic soda. After soaking in the liquid for a day and night, 20~3
A method of immersing the coating in a highly concentrated caustic soda solution of 0 weight for several hours is desirable from the viewpoint of imparting durability to the coating.

本願第１０発明の酸化ニッケルの溶射被覆を有する論極
拡、ニッケルの溶射被覆を有する陰極よりも、水素過電
圧、耐食性ともに優れたものである。また、本願第２の
発明の酸化ニッケルと犠牲金属との混合溶射被覆から犠
牲金属を溶出除去してなる陰極線、微多孔質の酸化ニッ
ケル被覆を有し、水素過電圧値が更に低く、優れたもの
となる。The cathode having a nickel oxide spray coating according to the tenth invention of the present application is superior to the cathode having a nickel spray coating in both hydrogen overvoltage and corrosion resistance. In addition, the cathode ray obtained by eluting and removing the sacrificial metal from the mixed sprayed coating of nickel oxide and sacrificial metal of the second invention of the present application, which has a microporous nickel oxide coating, has an even lower hydrogen overvoltage value, and is excellent. becomes.

実施例１ 軟鋼板（２００■×６００■）、ニッケル板（２００■
×６００■）、及び軟鋼板にプラズマ溶射によｐニッケ
ル層（厚さ５０μ）を設けた一基板（２００■×６００
閤）各々に粒径１０〜１００μの酸化ニッケル粉末をプ
ラズマ溶射して試料１〜３を作成した。グッズマ済射に
敵、プラズマダイン社製プラズマトｏｙＳＱ１００を使
用し、形成された酸化ニッケル層の厚さはいずれも１０
０μであうた。各試料から３０ｍＸ３０■の試片を切ｐ
出し、下記の条件下で陰極としての初期水素過電圧を測
定しえ。Example 1 Mild steel plate (200cm x 600cm), nickel plate (200cm
×600■), and one substrate (200■×600μ) with a p-nickel layer (thickness 50μ) formed on a mild steel plate by plasma spraying.
Samples 1 to 3 were prepared by plasma spraying nickel oxide powder with a particle size of 10 to 100 μm to each sample. We used Plasma Toy SQ100 manufactured by Plasma Dyne, which is the enemy of goods mass shooting, and the thickness of the nickel oxide layer formed was 10 mm.
I fired at 0μ. Cut a 30m x 30cm piece from each sample.
and measure the initial hydrogen overvoltage as a cathode under the following conditions.

水酸化ナトリクム水ｓｅｎ度　　　　　　１０ｗｔ％温
　　度　　　　　　　　　　　　　　　　　　７５℃電
ｔＩＩ１１１度　　　　　　　　　　　　　　５０　Ａ
／ｄｍ”陽　極　　　　　　　　　　　　　ニッケル板
照會電１ｉ　　　　　　　　　　　　　　　Ｈｐ／Ｈｔ
Ｏ上記の１〜３の試料を各々陰極として用い、陽極とし
てルテニウム酸化物被覆チタンを使用し、會フッ素スル
フォン駿系イオン交換膜（デ瓢ボン社製ナフィオン２２
７）で仕切られ九イオン交換属電解槽において食塩の電
解を行った。電流密度はｓ　ｏ　Ａ／ｄｍ”、陰極室か
らの抜き出しカセイソーダ水溶液の濃度は２０重量−と
した。１２０日間の連続運転を行った後、上記と同様に
して電解試験後の水素過電圧を測定した。Sodium hydroxide water Sen degree 10wt% Temperature 75°C Electricity II 111° 50 A
/dm” Anode Nickel plate photoelectric 1i Hp/Ht
Samples 1 to 3 above were used as cathodes, titanium coated with ruthenium oxide was used as an anode, and a fluorine sulfone ion exchange membrane (Nafion 22 manufactured by Dehyobong Co., Ltd.) was used.
Salt was electrolyzed in a nine ion-exchange metal electrolytic tank partitioned by 7). The current density was s o A/dm", and the concentration of the caustic soda aqueous solution extracted from the cathode chamber was 20% by weight. After 120 days of continuous operation, the hydrogen overvoltage after the electrolytic test was measured in the same manner as above. .

初期水素過電圧及び電解試験後の水素過電圧の測定値を
表１に示す。また、電解槽の停止と通電を１０回繰ｐ返
し友が、陰極電位及び陰極表面層に変化は見られなかっ
た。The measured values of the initial hydrogen overvoltage and the hydrogen overvoltage after the electrolytic test are shown in Table 1. Further, even after stopping and energizing the electrolytic cell 10 times, no change was observed in the cathode potential or cathode surface layer.

表　１ 比較例１ 軟鋼板（２００■×６００■）に、グッズマダイン社製
グツズ！トロン８Ｇを使用して粒径１０〜１００μのニ
ッケル粉末をプラズマ溶射して１００μの厚さのニッケ
ル層を形成した試料から５０■Ｘ３０−の試片を切夛出
し、実施例１と同様にして初期水素過電圧及び電解試験
後の水素過電圧を測定し九とζろ各々２４０　ｍＶ、２
５０　ｍＶであった。Table 1 Comparative Example 1 Guts made by Goods Madine Co., Ltd. on a mild steel plate (200×600×)! A 50cm x 30mm sample was cut out from a sample in which a 100μ thick nickel layer was formed by plasma spraying nickel powder with a particle size of 10 to 100μ using Tron 8G, and the same procedure as in Example 1 was taken. The initial hydrogen overvoltage and the hydrogen overvoltage after the electrolytic test were measured and were 240 mV and 2, respectively.
It was 50 mV.

実施例２ 軟鋼板にプラズマ溶射によシニッケル層（厚さ５０Ｐ）
を設は九基板（２００ｗＸ’６００■）に、酸化ニッケ
ル粉とアル建ニウム粉（いずれも粒径１０〜１００声）
からなり、体積百分率が各々５０１５０．６０／４０．
７０／３０．８０／２０の混合粉末をプラズマダイン社
製プラズマ溶射シＢＧ１００を使用しプッズ−ｆ＃ｌｌ
射し、試料４〜７を作成し友。Example 2 Plasma sprayed nickel layer on mild steel plate (thickness 50P)
9 substrates (200w x '600cm) are coated with nickel oxide powder and aluminum powder (particle size 10-100cm)
each with a volume percentage of 50150.60/40.
A mixed powder of 70/30.80/20 was sprayed using Plasma Dyne's plasma spraying machine BG100.
Then, create samples 4 to 7.

被覆層の厚さはいずれ４１００μとした。各試料から５
０箇×３０−の試片を切９出し、５重量−のカセイソー
ダ水溶液に一昼夜浸漬後、２０重量−のカセイソーダ水
溶液に５時間浸漬し、更に同Ｓｍ中７０〜７５℃に加温
状態で５時間浸漬して被覆層中からアル（＝ラム成分を
溶出除去した。The thickness of the coating layer was 4100μ. 5 from each sample
Cut 9 x 30 specimens, immerse them in a 5-weight caustic soda aqueous solution overnight, immerse them in a 20-weight caustic soda aqueous solution for 5 hours, and then heat them to 70-75°C in the same Sm solution for 5 hours. The aluminum (=rum) component was eluted and removed from the coating layer by immersion for a period of time.

このようにして作成された試料について実施例１と同様
にして初期水素過電圧を測定し、また、実施例１と同様
の電解条件下２５０日電解試験を行っ死後の水素過電圧
をＩｌｌ定した結果を表２に示す。The initial hydrogen overvoltage of the sample thus prepared was measured in the same manner as in Example 1, and the postmortem hydrogen overvoltage was determined by conducting a 250-day electrolytic test under the same electrolytic conditions as in Example 1. It is shown in Table 2.

また、電解槽の停止と通電を１０回繰り返したが、陰極
電位及び陰極表面に変化は生じなかった。Further, although the electrolytic cell was stopped and energized 10 times, no change occurred in the cathode potential or the cathode surface.

Claims (1)

【特許請求の範囲】[Claims] （１）　　導電Ｉｋｍ体表面上に、溶射によ〉酸化ニッ
ケルＯ被覆層を設けてなる電解用陰極。 に）導電性基体が、鉄、ニッケ・ル、銅又社これらＯ合
金かｂｔｋｈａ＃上Ｋｘツケルを溶射したもＯ″ｅ魯り
特許請求０１１１１第（１）項記載の電解用陰極。 に）導電愉基体貴藺上に、溶射によ〕酸化品ツケルと１
憧金属とＯ１１金被覆層を設けた後、該被覆層よｐ＠牲
金金属１１１出除去してなる電解用−極。 （旬　体積１分率で、酸化品ッケル看車５０〜９０−と
犠噛金属湯車ｓＯ〜１０４０割会で溶射する善許請京Ｏ
聰閤第に）項記載０電鱗用陰極。 に）１愉金属がアル電エクムである特許請求の範囲第に
）項記載Ｏ電解用陰極。 （句　導電性基体が、鉄、ニッケル、銅又は辷れらＯ合
金からｔｋる基材上にニッケルを湊射しえもＯ″ｅ番る
特許請求ｏｍｗｓ第（句項記載の電解用陰極。(1) An electrolytic cathode in which a nickel oxide O coating layer is provided on the surface of a conductive Ikm body by thermal spraying. 2) The electrolytic cathode described in paragraph (1) of patent claim 01111, in which the conductive substrate is made of iron, nickel, copper alloys, or alloys of these materials, or is thermally sprayed with Kx on btkha#. Oxide product 1 is applied by thermal spraying onto the conductive substrate.
An electrolytic electrode formed by providing a gold coating layer with a sacrificial metal and removing the p@ sacrificial metal 111 from the coating layer. (1% by volume, thermal spraying with 50~90% of oxidized product and 1040% of sacrificial metal steamer)
Cathode for electric scales described in Section 0. 2) The cathode for electrolysis according to claim 1), wherein the metal is Alden Ecum. (The electrolytic cathode described in Patent Claim No. OMWS), wherein the conductive substrate is made of iron, nickel, copper or an O alloy by injecting nickel onto the substrate.