JPH0465913B2 - - Google Patents
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- Publication number
- JPH0465913B2 JPH0465913B2 JP17091185A JP17091185A JPH0465913B2 JP H0465913 B2 JPH0465913 B2 JP H0465913B2 JP 17091185 A JP17091185 A JP 17091185A JP 17091185 A JP17091185 A JP 17091185A JP H0465913 B2 JPH0465913 B2 JP H0465913B2
- Authority
- JP
- Japan
- Prior art keywords
- electrode
- corrosion resistance
- group
- alloy
- amorphous
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- 229910000808 amorphous metal alloy Inorganic materials 0.000 claims description 19
- 238000005868 electrolysis reaction Methods 0.000 claims description 19
- 230000000694 effects Effects 0.000 claims description 18
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 14
- 229910052719 titanium Inorganic materials 0.000 claims description 11
- 239000000203 mixture Substances 0.000 claims description 10
- 229910052697 platinum Inorganic materials 0.000 claims description 9
- 239000007864 aqueous solution Substances 0.000 claims description 7
- 229910052758 niobium Inorganic materials 0.000 claims description 6
- 229910052715 tantalum Inorganic materials 0.000 claims description 6
- 229910052726 zirconium Inorganic materials 0.000 claims description 6
- 229910052741 iridium Inorganic materials 0.000 claims description 4
- 229910052763 palladium Inorganic materials 0.000 claims description 4
- 229910052703 rhodium Inorganic materials 0.000 claims description 4
- 229910052707 ruthenium Inorganic materials 0.000 claims description 4
- 239000007788 liquid Substances 0.000 claims description 2
- 229910052759 nickel Inorganic materials 0.000 claims description 2
- 238000005260 corrosion Methods 0.000 description 36
- 230000007797 corrosion Effects 0.000 description 36
- 229910045601 alloy Inorganic materials 0.000 description 18
- 239000000956 alloy Substances 0.000 description 18
- 239000007772 electrode material Substances 0.000 description 15
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 14
- 239000002253 acid Substances 0.000 description 11
- 239000000243 solution Substances 0.000 description 11
- 239000010936 titanium Substances 0.000 description 11
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 9
- 239000000463 material Substances 0.000 description 9
- 239000003929 acidic solution Substances 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- 239000010955 niobium Substances 0.000 description 7
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 6
- 230000003197 catalytic effect Effects 0.000 description 6
- 230000010287 polarization Effects 0.000 description 6
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 5
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 5
- 239000011651 chromium Substances 0.000 description 5
- 229910001882 dioxygen Inorganic materials 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 239000007769 metal material Substances 0.000 description 5
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 4
- 229910000978 Pb alloy Inorganic materials 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 230000001590 oxidative effect Effects 0.000 description 4
- 229910001256 stainless steel alloy Inorganic materials 0.000 description 4
- 230000004913 activation Effects 0.000 description 3
- 239000010407 anodic oxide Substances 0.000 description 3
- 238000004090 dissolution Methods 0.000 description 3
- 238000005363 electrowinning Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 238000007747 plating Methods 0.000 description 3
- 238000007712 rapid solidification Methods 0.000 description 3
- 239000010948 rhodium Substances 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- 239000010405 anode material Substances 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000010802 sludge Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 1
- 238000003723 Smelting Methods 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 239000012300 argon atmosphere Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000003487 electrochemical reaction Methods 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 238000010828 elution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000012456 homogeneous solution Substances 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000005468 ion implantation Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- YADSGOSSYOOKMP-UHFFFAOYSA-N lead dioxide Inorganic materials O=[Pb]=O YADSGOSSYOOKMP-UHFFFAOYSA-N 0.000 description 1
- 229910000464 lead oxide Inorganic materials 0.000 description 1
- HTUMBQDCCIXGCV-UHFFFAOYSA-N lead oxide Chemical class [O-2].[Pb+2] HTUMBQDCCIXGCV-UHFFFAOYSA-N 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 239000005300 metallic glass Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 1
- 238000002161 passivation Methods 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 150000003057 platinum Chemical class 0.000 description 1
- 230000008261 resistance mechanism Effects 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 229910001925 ruthenium oxide Inorganic materials 0.000 description 1
- YBCAZPLXEGKKFM-UHFFFAOYSA-K ruthenium(iii) chloride Chemical compound [Cl-].[Cl-].[Cl-].[Ru+3] YBCAZPLXEGKKFM-UHFFFAOYSA-K 0.000 description 1
- WOCIAKWEIIZHES-UHFFFAOYSA-N ruthenium(iv) oxide Chemical compound O=[Ru]=O WOCIAKWEIIZHES-UHFFFAOYSA-N 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- VSZWPYCFIRKVQL-UHFFFAOYSA-N selanylidenegallium;selenium Chemical compound [Se].[Se]=[Ga].[Se]=[Ga] VSZWPYCFIRKVQL-UHFFFAOYSA-N 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 230000002459 sustained effect Effects 0.000 description 1
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 230000004580 weight loss Effects 0.000 description 1
Description
（発明の利用分野）
本発明は、例えば強酸性溶液電解用電極材料と
して、高耐食性および高電極触媒活性を兼備した
電解用電極材料に関するものである。
（発明の背景）
非鉄金属の電解採取法は一段で高純度金属が得
られるという点で乾式法よりも優れ、特に亜鉛、
マンガン、銅およびクロム等の製錬では重要な地
位を占めている。
これらの電解採取では、一般に、硫酸酸性電解
が採用され、陽極として鉛合金が広く使用されて
いる。これらは鉛合金の価格が安くかつ成型が容
易であり、酸化物が酸性溶液中で比較的安定であ
るという鉛合金の特質によるものである。
しかし、鉛電極は、材料コストが安価なことか
ら特に電解採取用陽極として広く使用されている
ものの、電解時陽極表面に形成されるPbO2層は
剥離、脱落を繰り返し、浴の汚染を引き起こし、
この鉛酸化物のスラツジを陰極面での析出層に包
含してしまうこと、および隔膜電解の場合、この
スラツジによる膜目づまりのため電解電圧上昇を
引き起こすという問題がある。
またメツキ分野においても陽極に鉛合金が使用
されている例も多いが、高速メツキの技術が進歩
し、浴の高速流動下および高電解電密下での耐摩
耗性および耐食性が電極材料の重要な因子となつ
ている近時においては、電解液の汚染が問題とな
るような鉛合金電極の使用に換えて、白金又は白
金被覆チタン電極等が使用される場合が多くなつ
ている。この白金電極は、例えばチタン等の陽極
的耐食性基材上にメツキ法又は箔の接合法により
薄層をコーテイングまたはライニングし、陽極と
して使用に供される。
しかし、白金電極は高価格であるにもかかわら
ず、例えば硫酸酸性浴のような場合には、酸素ガ
ス発生過電圧が比較的高く、電極成型上の問題よ
り、剥離、傷耗が発生し、必ずしも永久的な信頼
性の高い電極とは言いがたい問題点がある。
またチタン基板上に塩化ルテニウムを空気中で
熱分解することによつて酸化ルテニウムを形成さ
せる陽極は、酸素過電圧が小さく、かつ導電性が
非常に高いという特徴をもち、陽極材料として有
望であるが、酸性溶液中では溶解が進行してチタ
ン基板の不働態化が進み、使用時間とともに電気
化学的活性が低下するという問題点を有してい
る。
更にまた、近時において高耐食性金属材料とし
て注目され、利用されてきているものに非晶質金
属材料があり、例えば、非晶質ステンレス合金
は、超耐食性とも言われる高耐食性、孔食等の局
部腐食の発生が極めて少ないものとして知られて
いる。この非晶質ステンレス合金の主たる耐食性
メカニズムは、非晶質合金基材が粒界等の結晶欠
陥を有さず、均一溶体であること、ならびに不働
態皮膜成能に優れていることから、欠陥のないき
わめて均一で優れた耐食性を有する不働態皮膜が
形成されることによる。
したがつて、かかる高耐食性すなわち電極素地
合金成分の均一分散性からして局部的で不均一な
腐食および反応がなく、安定した電解反応が期待
されるという点から非晶質合金を電解用電極材料
に供することが考えられる。
しかし、本発明が対象とするような電解用電極
用材料として所与の金属材料が有効に機能するた
めには、例えば陽分極下で耐食性ある陽極酸化皮
膜が形成されるだけでなく、この酸化皮膜が電子
伝導性を具備しなければならないものであるのに
対し、前記した非晶質ステンレス合金は、酸性浴
中自然浸漬時には、優れた耐食性を示すものの、
酸素ガス発生電位域のような陽分極下では、過不
働態溶解が進行するため、耐食性ある陽極材料と
しての使用はできない。これは、非晶質ステンレ
ス合金の耐食性向上に寄与している主たる元素が
Crであり、Crを主金属成分とする不働態皮膜が
自然浸漬状態で優れた耐食性を有するのに対し、
陽分極化ではCr+6イオンの溶出という形で過不働
態溶解が進行するからである。
非晶質合金の電解用電極材料としては、食塩電
解用のものが本発明者等によつて提案されている
（特開昭55−152143号、特開昭56−150148号参照）
が、これらの提案にかかる材料も、強酸性溶液中
では不働態破壊が起こるため、強酸性溶液中での
高耐食性は期待できない。
（発明の目的）
本発明は以上のような従来技術の種々の問題点
に鑑みなされたものであり、その目的は、腐食性
がきわめて激しい強酸性溶液電解のために耐食性
に優れた性質を有し、かつ優れた電極触媒活性を
備えた電極材料を提供するところにある。
（発明の概要）
而してかかる目的を実現するためになされた本
発明よりなる電解用電極材料の特徴は、タンタル
（Ta）と、ルテニウム（Ru）、ロジウム（Rh）
パラジウム（Pd）、イリジウム（Ir）、白金（Pt）
の群（第群の元素という）から選ばれた１種ま
たは２種以上の元素と、残部が実質的にニツケル
（Ni）とからなり、前記Taが25〜65原子％、好
ましくは35〜63原勺％、前記第群から選ばれた
元素が0.3〜45原子％、好ましくは１〜45原子％、
および前記Niが30原子％以上の組成を有する非
晶質合金であり、これをフツ化水素酸水溶液中に
浸す処理を施すことにより、きわめて優れた電極
触媒能を有する電解用電極材料を提供するところ
にある。
また本発明においては、前記したTaの一部は
チタン（Ti）、ジルコニウム（Zr）、ニオブ
（Nb）の群（第群の元素という）から選ばれた
１種または２種以上の元素に置換することができ
る。これらの第群の元素は、Taと同様にNiと
共存して非晶質構造を形成することができる元素
であり、かつ酸化性の強い条件の強酸性溶液中に
おいて不働態皮膜を形成する元素であることによ
る。ただし、これら第群の元素が示す強酸性溶
液中での耐食性効果はTaに比べて低いことから、
Taと全量置換することは適当でなく、Taと前記
第群の元素を共存させることができる含有率25
〜65原子％のうち、Taが20原子％以上であるこ
とが必要である。
本発明の合金が、前記した組成を有し、かつ非
晶質合金として構成された理由は次のことによ
る。すなわち、水溶液電圧の陽極のような酸化力
の高い環境で強酸化性溶液に曝されると、通常の
金属材料では容易に酸化され溶解する。したがつ
てこのような条件の下で金属材料を使用するため
には、安定な保護皮膜を形成する能力を金属材料
に付与する必要があり、更に、これを例えば陽極
として使用するためには、所定の電気化学反応に
対して特に優れた電極触媒活性と競合する反応に
対して不活性であるという反応選択性を備えてい
なければならない。
これらの特性は耐食性および優れた電極特性に
有効な元素を必要量含む合金を作ることによつて
一応得られるが、しかし、結晶質合金の場合には
多種多量の合金元素を添加すると、しばしば化学
的性質の異なる多相構造となり、所定の耐食性お
よび電極特性が実現しがたく、また多相構造にも
とづく化学的不均一性の発生はむしろ耐食性と安
定な電極特性に有害である場合が多い。
これらのことから、材料表面の不働態皮膜形成
によつて、強酸性水溶液中での高耐食性、高触媒
活性の具有を実現可能とした前記電極材料を見い
出し、これをフツ化水素酸水溶液中に浸す処理を
施すことにより、さらに優れた電極触媒能を有す
る電解用電極材料の発明に至つたのである。
次に本発明における各成分組成を限定する理由
を述べる。
Niは、本発明合金の基礎となる金属元素であ
つて、TaあるいはこれとTi、Zr、Nbの第群
の元素と共存して非晶質構造を形成する元素であ
る。したがつて本発明において、非晶質構造形成
のためにNiを30原子％以上添加することが必要
である。
Taは、陽極として使用されるような酸化性の
激しい環境の強酸性溶液中において、安定な不働
態皮膜を形成する元素であるが、著しく多量に添
加すると電極触媒活性を低下させるため添加量は
25〜65原子％とする必要がある。なおこのTaは、
前述の如くTi、ZrおよびNbの第群の元素に一
部置換することができ。しかし、Ti、Zrおよび
Nbの耐食性におよぼす効果は、Taに比べて劣
り、またTaと同様に著しく多量に添加すると電
極触媒活性を低下させる。したがつて、Taを20
原子％以上含むことを条件として、Ti、Zrおよ
びNbのいずれか１種または２種以上とTaの合計
が25〜65原子％にしなければならない。
Ru、Rh、Pd、IrおよびPtの第群の白金族元
素は、白金に含まれるといずれも不働態皮膜の一
部を構成して電極触媒活性を材料に付与する元素
であるが、これらのいずれか１種又は２種の合計
が0.3原子％末満では十分な電極触媒活性が得ら
れない。一方、これらの第群の元素はNiと同
様Ta、Ti、Zr、Nbなどと共存すると非晶質構
造を形成する元素であるが、高価であると共にあ
まり多量に添加しても効果の増幅はみられないの
で45原子％が上限である。したがつて、本発明に
おいて、前記第群の元素１種または２種以上の
添加量は0.3〜45原子％とする必要があり、好ま
しくは１〜45原子％とすることがよい。
なお、本発明の電解用電極材料は、Ta（第群
の元素により一部置換されている場合を含む）お
よび第群のいずれか１種または２種以上の元素
の他は、実質的にNiからなるものであるがＶ、
Cr、Mo、Ｗ、Fe、Co、Cu、Ag、Auなどの不
純物は総量で２原子％以下であれば含有されてい
ても差支えない。
本発明組成の非晶室合金はそのままでも特願昭
60−12311号に示されているごとく、強酸性溶液
中で高耐食性および高電極触媒活性を有する電解
用電極材料であるが本発明者らはさらに、鋭意研
究を進めた結果、本発明組成の非晶質合金をフツ
化水素酸水溶液中に浸すことによりさらに優れた
電極触媒活性を示すことも見い出し本発明に到達
したのである。
本発明の活性化非晶質合金は例えば、腐食性の
著しい酸性浴中でも陽分極下にて、耐食性が低下
することなく、きわめて優れた電極触媒活性を維
持するというおどろくべき特性を有していること
が明らかとなつた。すなわち、陽分極下では、活
性化非晶質合金でも当然陽極酸化皮膜が形成され
るが、陽極酸化皮膜の形成に伴なう電極触媒活性
の低減が見られず、例えば硫酸酸性浴中における
陽分極下での酸素ガス発生過電圧が、非晶質化し
たままの電極に比較して本発明の活性化非晶質合
金電極は200〜250mmＶ低減され、しかも、耐食性
は活性化しない元の非晶質合金と同レベルである
高活性、高耐食性電極を見い出したのである。
尚、本発明と同一組成の合金であつても、結晶
質合金においては、フツ化水素酸溶液による活性
化処理時に激しい水素ガス発生を伴なつた腐食が
進行し、これを仮に電極として用いても、優れた
耐食性は望めず、また優れた電極触媒活性の持続
は期待できない。従つて、本発明の合金組成を有
し、かつ、それらが非晶質合金であつて、初めて
フツ化水素酸溶液による活性化処理が電極として
触媒活性の向上に寄与し、従来にない、きわめて
優れた電極として機能する。
本発明の非晶質合金の作製は、既に広く用いら
れている種々の方法を用いて行なうことができ
る。例えば液体合金を超急冷凝固させる方法、気
相を経て非晶質合金を形成させる種々の方法、イ
オン注入によつて固体の長周期構造を破壊する方
法など非晶質合金を作製するいずれの方法でも適
用することができる。以上の組成の溶融合金を、
超急冷凝固させたり、スパツター・デポジシヨン
させるなどの適宜の作製方法によつて得られる非
晶質合金は、前記各元素が均一に固溶した単相合
金である。そのため、かかる非晶質合金をフツ化
水素酸溶液中で活性化処理を施すと、この表面に
きわめて均一な活性層が形成され、かかる非晶質
合金を強酸性溶液中で電極として用いると、その
表面にきわめて均一で高耐食性を有する保護皮膜
（不働態皮膜）が形成され、強酸性溶液中で使用
される電極材料として好適な特性を示すことがで
きる。
（実施例）
表１の各試料No.の組成になるように、夫々の原
料金属を混合し、高周波溶解法により、原料合金
を作製した。これらの合金を、アルゴン雰囲気中
で再溶融して、単ロール法を用いて、超急冷凝固
させることにより、厚さ0.02〜0.05mm、幅１〜３
mm、長さ３〜20ｍの非晶質合金薄板を得た。非晶
質構造形成の確認は、Ｘ線回析によつて行なつ
た。これら非晶質合金薄板より試料を切り出し、
50℃の1MHF水溶液中に30分浸漬することによ
り、活性化処理を施し、これを陽極として用い
て、1M H2SO4水溶液の電解を行なつた。
腐食速度は、500A／m2の定電流電解を10日間
行ない、重量減少から換算して求めた。表２は、
試料を陽極として酸素ガスを発生させた際、測定
された500A／m2の電流密度における試料電極の
飽和甘汞電極（SCE）で照合した電位および腐食
速度をまとめたものである。
表２に示す結果より、各試料は、硫酸酸性浴電
解の陽極として用いたとき優れた耐食性と、きわ
めて低い酸素ガス発生過電圧を有していることが
わかる。
(Field of Application of the Invention) The present invention relates to an electrode material for electrolysis that has both high corrosion resistance and high electrode catalytic activity, for example as an electrode material for strong acid solution electrolysis. (Background of the invention) The electrowinning method for nonferrous metals is superior to the dry method in that high-purity metals can be obtained in one step.
It plays an important role in the smelting of manganese, copper, chromium, etc. These electrowinning methods generally employ sulfuric acid acid electrolysis, and lead alloys are widely used as anodes. These characteristics are due to the characteristics of lead alloys, such as their low cost and easy molding, and their oxides being relatively stable in acidic solutions. However, although lead electrodes are widely used as anodes for electrowinning due to their low material cost, the PbO2 layer formed on the anode surface during electrolysis repeatedly peels off and falls off, causing bath contamination.
There is a problem in that this lead oxide sludge is included in the deposited layer on the cathode surface, and in the case of diaphragm electrolysis, this sludge clogs the membrane, causing an increase in electrolytic voltage. In addition, lead alloys are often used for anodes in the plating field, but as high-speed plating technology advances, wear resistance and corrosion resistance under high-speed bath flow and high electrolytic density are important for electrode materials. In recent years, platinum or platinum-coated titanium electrodes are increasingly being used instead of lead alloy electrodes, where electrolyte contamination is a problem. This platinum electrode is used as an anode by coating or lining a thin layer on an anodic corrosion-resistant substrate such as titanium by plating or foil bonding. However, despite the high price of platinum electrodes, when used in sulfuric acid acid baths, for example, the oxygen gas generation overvoltage is relatively high, and problems with electrode molding can cause peeling and wear. There are some problems that make it difficult to say that this is a permanently reliable electrode. Furthermore, an anode in which ruthenium oxide is formed on a titanium substrate by thermally decomposing ruthenium chloride in air has the characteristics of low oxygen overvoltage and extremely high conductivity, making it a promising anode material. However, in an acidic solution, dissolution progresses and the titanium substrate becomes passivated, resulting in a problem that the electrochemical activity decreases over time of use. Furthermore, in recent years, amorphous metal materials have been attracting attention and being used as highly corrosion-resistant metal materials.For example, amorphous stainless steel alloys have high corrosion resistance, which is also called super corrosion resistance, and corrosion resistance such as pitting corrosion. It is known to cause extremely little local corrosion. The main corrosion resistance mechanism of this amorphous stainless steel alloy is that the amorphous alloy base material has no crystal defects such as grain boundaries, is a homogeneous solution, and has excellent ability to form a passive film. This is because a passive film is formed that is extremely uniform and has excellent corrosion resistance. Therefore, amorphous alloys are used as electrodes for electrolysis because of their high corrosion resistance, that is, the uniform dispersion of the electrode base alloy components, which prevent localized and uneven corrosion and reactions, and are expected to produce stable electrolytic reactions. It is conceivable to use it as a material. However, in order for a given metal material to function effectively as an electrode material for electrolysis, such as the one targeted by the present invention, it is necessary not only to form a corrosion-resistant anodic oxide film under anodic polarization, but also to While the film must have electronic conductivity, the amorphous stainless steel alloy described above shows excellent corrosion resistance when naturally immersed in an acid bath.
Under anodic polarization, such as in the oxygen gas generation potential range, hyperpassive state dissolution proceeds, so it cannot be used as a corrosion-resistant anode material. This means that the main element that contributes to improving the corrosion resistance of amorphous stainless steel alloys is
Cr, and while a passive film containing Cr as the main metal component has excellent corrosion resistance in natural immersion conditions,
This is because during anodic polarization, hyperpassive dissolution proceeds in the form of elution of Cr +6 ions. The present inventors have proposed an amorphous alloy electrode material for salt electrolysis (see JP-A-55-152143 and JP-A-56-150148).
However, the materials proposed in these proposals also undergo passivation destruction in strong acid solutions, so high corrosion resistance in strong acid solutions cannot be expected. (Object of the Invention) The present invention has been made in view of the various problems of the prior art as described above, and its purpose is to provide a material with excellent corrosion resistance for use in strongly acidic solution electrolysis, which is extremely corrosive. An object of the present invention is to provide an electrode material having excellent electrocatalytic activity. (Summary of the Invention) The electrolytic electrode material of the present invention, which was made to achieve the above object, is characterized by the fact that it contains tantalum (Ta), ruthenium (Ru), and rhodium (Rh).
Palladium (Pd), Iridium (Ir), Platinum (Pt)
one or more elements selected from the group (referred to as the elements of the group) and the balance substantially consists of nickel (Ni), and the Ta content is 25 to 65 at%, preferably 35 to 63 %, the element selected from the above group is 0.3 to 45 atomic %, preferably 1 to 45 atomic %,
and an amorphous alloy having a composition of 30 atomic % or more of Ni, which is immersed in a hydrofluoric acid aqueous solution to provide an electrode material for electrolysis having extremely excellent electrode catalytic ability. There it is. Further, in the present invention, a part of the above-mentioned Ta is replaced with one or more elements selected from the group of titanium (Ti), zirconium (Zr), and niobium (Nb) (referred to as the group element). can do. These group elements are elements that can coexist with Ni to form an amorphous structure, similar to Ta, and are elements that form a passive film in a strongly acidic solution under highly oxidizing conditions. By being. However, since the corrosion resistance effect of these group elements in strong acidic solutions is lower than that of Ta,
It is not appropriate to replace the entire amount with Ta, and the content is 25 to allow Ta and the elements of the above group to coexist.
Of the ~65 atomic %, Ta needs to be 20 atomic % or more. The reason why the alloy of the present invention has the above-mentioned composition and is configured as an amorphous alloy is as follows. That is, when exposed to a strongly oxidizing solution in a highly oxidizing environment such as an aqueous solution voltage anode, ordinary metal materials are easily oxidized and dissolved. Therefore, in order to use a metal material under such conditions, it is necessary to provide the metal material with the ability to form a stable protective film, and furthermore, in order to use it as an anode, for example, It must have a particularly good electrocatalytic activity for a given electrochemical reaction and a reaction selectivity of inertness for competing reactions. These properties can be obtained by making an alloy containing the necessary amounts of elements effective for corrosion resistance and excellent electrode properties, but in the case of crystalline alloys, adding a large number of alloying elements of various types often causes chemical problems. This results in a multi-phase structure with different physical properties, making it difficult to achieve desired corrosion resistance and electrode properties, and the occurrence of chemical non-uniformity based on the multi-phase structure is often detrimental to corrosion resistance and stable electrode properties. Based on these findings, we have discovered an electrode material that can achieve high corrosion resistance and high catalytic activity in a strongly acidic aqueous solution by forming a passive film on the surface of the material. By applying a soaking treatment, they were able to invent an electrode material for electrolysis that has even better electrode catalytic ability. Next, the reason for limiting the composition of each component in the present invention will be described. Ni is a metal element that is the basis of the alloy of the present invention, and is an element that forms an amorphous structure in coexistence with Ta or elements of the group of Ti, Zr, and Nb. Therefore, in the present invention, it is necessary to add 30 atomic percent or more of Ni in order to form an amorphous structure. Ta is an element that forms a stable passive film in strongly acidic solutions in highly oxidizing environments such as those used as anodes.
It needs to be 25 to 65 at%. Note that this Ta is
As mentioned above, it can be partially substituted with elements of the group Ti, Zr, and Nb. However, Ti, Zr and
The effect of Nb on corrosion resistance is inferior to that of Ta, and like Ta, when added in a significantly large amount, it reduces the electrode catalyst activity. Therefore, Ta is 20
The total content of any one or more of Ti, Zr, and Nb and Ta must be 25 to 65 atomic %, provided that the content is 25 to 65 atomic %. The platinum group elements of Ru, Rh, Pd, Ir, and Pt are elements that, when included in platinum, form part of the passive film and impart electrocatalytic activity to the material. If the total content of any one or both of them is less than 0.3 atomic %, sufficient electrocatalytic activity cannot be obtained. On the other hand, like Ni, these elements in the group form an amorphous structure when they coexist with Ta, Ti, Zr, Nb, etc., but they are expensive and the effect will not be amplified even if they are added in too large a quantity. Since it cannot be seen, the upper limit is 45 atom%. Therefore, in the present invention, the amount of one or more elements of the above-mentioned group added must be 0.3 to 45 atomic %, preferably 1 to 45 atomic %. In addition, the electrode material for electrolysis of the present invention contains substantially Ni except for Ta (including the case where it is partially substituted with an element of the group) and any one or more elements of the group. It consists of V,
Impurities such as Cr, Mo, W, Fe, Co, Cu, Ag, and Au may be contained as long as the total amount is 2 atomic % or less. The amorphous chamber alloy having the composition of the present invention can be used as is in the patent application.
As shown in No. 60-12311, it is an electrode material for electrolysis that has high corrosion resistance and high electrocatalytic activity in a strong acid solution. It was also discovered that immersing an amorphous alloy in an aqueous hydrofluoric acid solution shows even more excellent electrocatalytic activity, leading to the present invention. The activated amorphous alloy of the present invention has the surprising property of maintaining extremely excellent electrocatalytic activity without a decrease in corrosion resistance even under anodic polarization even in highly corrosive acid baths. It became clear. In other words, under anodic polarization, an anodic oxide film is naturally formed even on activated amorphous alloys, but the reduction in electrocatalytic activity accompanying the formation of an anodic oxide film is not observed. The activated amorphous alloy electrode of the present invention has an oxygen gas generation overvoltage under polarization that is reduced by 200 to 250 mmV compared to an electrode that remains amorphous. They discovered an electrode with high activity and high corrosion resistance that is on the same level as high-quality alloys. Even if the alloy has the same composition as that of the present invention, corrosion progresses with intense hydrogen gas generation during activation treatment with a hydrofluoric acid solution in a crystalline alloy. However, excellent corrosion resistance cannot be expected, nor can sustained excellent electrode catalytic activity be expected. Therefore, if the alloy has the composition of the present invention and is an amorphous alloy, the activation treatment with a hydrofluoric acid solution will contribute to improving the catalytic activity as an electrode for the first time. Works as an excellent electrode. The amorphous alloy of the present invention can be produced using various methods that are already widely used. Any method of producing an amorphous alloy, such as ultra-rapid solidification of a liquid alloy, various methods of forming an amorphous alloy through a gas phase, or destruction of the long-period structure of a solid by ion implantation. It can also be applied. Molten alloy with the above composition,
An amorphous alloy obtained by an appropriate manufacturing method such as ultra-rapid solidification or sputter deposition is a single-phase alloy in which each of the above-mentioned elements is uniformly dissolved in solid solution. Therefore, when such an amorphous alloy is activated in a hydrofluoric acid solution, an extremely uniform active layer is formed on its surface, and when such an amorphous alloy is used as an electrode in a strong acid solution, A protective film (passive film) that is extremely uniform and has high corrosion resistance is formed on the surface, and can exhibit characteristics suitable as an electrode material used in a strongly acidic solution. (Example) Raw material metals were mixed to have the composition of each sample No. in Table 1, and raw material alloys were produced by high frequency melting. These alloys are remelted in an argon atmosphere and solidified by ultra-rapid solidification using a single roll method to form a material with a thickness of 0.02 to 0.05 mm and a width of 1 to 3 mm.
An amorphous alloy thin plate with a length of 3 to 20 m was obtained. The formation of an amorphous structure was confirmed by X-ray diffraction. Samples were cut out from these amorphous alloy thin plates,
Activation treatment was performed by immersing it in a 1M HF aqueous solution at 50°C for 30 minutes, and this was used as an anode to electrolyze a 1M H 2 SO 4 aqueous solution. The corrosion rate was calculated from the weight loss after 10 days of constant current electrolysis at 500 A/m 2 . Table 2 is
This is a summary of the potential and corrosion rate compared with the sample electrode's saturated gas electrode (SCE) at a current density of 500 A/m 2 measured when oxygen gas was generated using the sample as an anode. The results shown in Table 2 show that each sample has excellent corrosion resistance and extremely low oxygen gas generation overvoltage when used as an anode for sulfuric acid acid bath electrolysis.
【表】【table】
【表】【table】
【表】【table】
【表】
（発明の効果）
以上詳述したとおり、本発明の電解用電極材料
は、例えば強酸性電解用溶液として用いると効率
よく酸素を発生しかつ、激しい腐食性環境におい
ても安定な不働態皮膜を形成して腐食されない高
い電極触媒活性と高耐食性を示すものであり、ま
た本発明の合金電極材料の作製には既に広く用い
られている非晶質合金作製の技術のいずれも適用
できるため、特殊な装置を改めて必要とすること
なく作製でき、その有無性は極めて大なるもので
ある。[Table] (Effects of the Invention) As detailed above, the electrode material for electrolysis of the present invention efficiently generates oxygen when used as a solution for strong acid electrolysis, and has a stable passive state even in a severely corrosive environment. The alloy exhibits high electrocatalytic activity and high corrosion resistance without forming a film and corroding, and any of the already widely used amorphous alloy production techniques can be applied to the production of the alloy electrode material of the present invention. , it can be produced without the need for special equipment, and its availability is extremely significant.
Claims (1)
から選ばれた１種または２種以上の元素と、残部
が実質的にNiとからなり、前記Taが25〜65原子
％、前記第群から選ばれた元素が0.3〜45原子
％、および前記Niが30原子％以上の組成を有す
る非晶質合金をフツ化水素酸水溶液中に浸し、電
極活性を向上させたことを特徴とする電解用電
極。 ２ Taと、Ru、Rh、Pd、Ir、Ptの第１群の内
から選ばれた１種または２種以上の元素と、Ti、
Zr、Nbの第群の内から選ばれた１種または２
種以上の元素と、残部が実質的にNiとからなり、
前記Taが20原子％以上であつて、これと前記第
群から選ばれた元素が0.3〜45原子％、および
前記Niが30原子％以上の組成を有する非晶質合
金をフツ化水素酸水溶液中に浸し、電極活性を向
上させたことを特徴とする電解用電極。[Scope of Claims] 1 Consisting of Ta, one or more elements selected from the first group of Ru, Rh, Pd, Ir, and Pt, and the remainder substantially Ni, An amorphous alloy having a composition of 25 to 65 at% Ta, 0.3 to 45 at% of an element selected from the above group, and 30 at% or more of Ni is immersed in an aqueous solution of hydrofluoric acid, and an electrode An electrode for electrolysis characterized by improved activity. 2 Ta, one or more elements selected from the first group of Ru, Rh, Pd, Ir, and Pt, and Ti,
One or two selected from the group of Zr and Nb
Consisting of elements larger than species and the remainder being essentially Ni,
An amorphous alloy having a composition in which Ta is 20 atomic % or more, an element selected from the first group is 0.3 to 45 atomic %, and Ni is 30 atomic % or more is dissolved in a hydrofluoric acid aqueous solution. An electrode for electrolysis characterized by being immersed in a liquid to improve electrode activity.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17091185A JPS6233790A (en) | 1985-08-02 | 1985-08-02 | Activated amorphous alloy electrode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17091185A JPS6233790A (en) | 1985-08-02 | 1985-08-02 | Activated amorphous alloy electrode |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6233790A JPS6233790A (en) | 1987-02-13 |
| JPH0465913B2 true JPH0465913B2 (en) | 1992-10-21 |
Family
ID=15913623
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17091185A Granted JPS6233790A (en) | 1985-08-02 | 1985-08-02 | Activated amorphous alloy electrode |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6233790A (en) |
Families Citing this family (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE69027070T2 (en) * | 1989-02-28 | 1996-10-24 | Canon Kk | NON-MONOCRISTALLINE FABRIC CONTAINING IRIDIUM, TANTAL AND ALUMINUM |
| JP2625316B2 (en) * | 1992-05-11 | 1997-07-02 | 株式会社ライムズ | Composite corrosion resistant material and method for producing the same |
| US9339278B2 (en) | 2006-02-27 | 2016-05-17 | Biomet Manufacturing, Llc | Patient-specific acetabular guides and associated instruments |
| US9173661B2 (en) | 2006-02-27 | 2015-11-03 | Biomet Manufacturing, Llc | Patient specific alignment guide with cutting surface and laser indicator |
| US9289253B2 (en) | 2006-02-27 | 2016-03-22 | Biomet Manufacturing, Llc | Patient-specific shoulder guide |
| JP4916040B1 (en) * | 2011-03-25 | 2012-04-11 | 学校法人同志社 | Electrolytic sampling anode and electrolytic sampling method using the anode |
| US20130001121A1 (en) | 2011-07-01 | 2013-01-03 | Biomet Manufacturing Corp. | Backup kit for a patient-specific arthroplasty kit assembly |
| US9386993B2 (en) | 2011-09-29 | 2016-07-12 | Biomet Manufacturing, Llc | Patient-specific femoroacetabular impingement instruments and methods |
| KR20130046337A (en) | 2011-10-27 | 2013-05-07 | 삼성전자주식회사 | Multi-view device and contol method thereof, display apparatus and contol method thereof, and display system |
| US9301812B2 (en) | 2011-10-27 | 2016-04-05 | Biomet Manufacturing, Llc | Methods for patient-specific shoulder arthroplasty |
| US9839438B2 (en) | 2013-03-11 | 2017-12-12 | Biomet Manufacturing, Llc | Patient-specific glenoid guide with a reusable guide holder |
| US9498233B2 (en) | 2013-03-13 | 2016-11-22 | Biomet Manufacturing, Llc. | Universal acetabular guide and associated hardware |
| US9826981B2 (en) | 2013-03-13 | 2017-11-28 | Biomet Manufacturing, Llc | Tangential fit of patient-specific guides |
| US9833245B2 (en) | 2014-09-29 | 2017-12-05 | Biomet Sports Medicine, Llc | Tibial tubercule osteotomy |
| US10568647B2 (en) | 2015-06-25 | 2020-02-25 | Biomet Manufacturing, Llc | Patient-specific humeral guide designs |
| US10226262B2 (en) | 2015-06-25 | 2019-03-12 | Biomet Manufacturing, Llc | Patient-specific humeral guide designs |
-
1985
- 1985-08-02 JP JP17091185A patent/JPS6233790A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6233790A (en) | 1987-02-13 |
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