JPS62222037A - Zirconium-base alloy excellent in resistance to oxidation by nitric acid - Google Patents
Zirconium-base alloy excellent in resistance to oxidation by nitric acidInfo
- Publication number
- JPS62222037A JPS62222037A JP6379786A JP6379786A JPS62222037A JP S62222037 A JPS62222037 A JP S62222037A JP 6379786 A JP6379786 A JP 6379786A JP 6379786 A JP6379786 A JP 6379786A JP S62222037 A JPS62222037 A JP S62222037A
- Authority
- JP
- Japan
- Prior art keywords
- nitric acid
- zirconium
- corrosion
- potential
- resistance
- 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.)
- Granted
Links
- 229910045601 alloy Inorganic materials 0.000 title claims abstract description 13
- 239000000956 alloy Substances 0.000 title claims abstract description 13
- 230000003647 oxidation Effects 0.000 title claims abstract description 8
- 238000007254 oxidation reaction Methods 0.000 title claims abstract description 8
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 title abstract description 35
- 229910017604 nitric acid Inorganic materials 0.000 title abstract description 35
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 17
- 239000012535 impurity Substances 0.000 claims abstract description 5
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims description 37
- 229910052726 zirconium Inorganic materials 0.000 claims description 37
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 16
- 239000010936 titanium Substances 0.000 claims description 16
- 230000007797 corrosion Effects 0.000 abstract description 42
- 238000005260 corrosion Methods 0.000 abstract description 42
- 229910001069 Ti alloy Inorganic materials 0.000 abstract description 3
- 230000000694 effects Effects 0.000 abstract description 3
- 239000000203 mixture Substances 0.000 abstract 2
- 239000000654 additive Substances 0.000 abstract 1
- 230000000996 additive effect Effects 0.000 abstract 1
- 238000009835 boiling Methods 0.000 description 13
- 230000001590 oxidative effect Effects 0.000 description 11
- 230000010287 polarization Effects 0.000 description 10
- 239000000243 solution Substances 0.000 description 10
- 229910001220 stainless steel Inorganic materials 0.000 description 8
- 239000010935 stainless steel Substances 0.000 description 7
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 6
- -1 Fe(III) ions Chemical class 0.000 description 4
- 150000002500 ions Chemical class 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 238000005868 electrolysis reaction Methods 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 229910002651 NO3 Inorganic materials 0.000 description 2
- 229910052778 Plutonium Inorganic materials 0.000 description 2
- 229910052770 Uranium Inorganic materials 0.000 description 2
- 238000002848 electrochemical method Methods 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- OYEHPCDNVJXUIW-UHFFFAOYSA-N plutonium atom Chemical compound [Pu] OYEHPCDNVJXUIW-UHFFFAOYSA-N 0.000 description 2
- 238000012958 reprocessing Methods 0.000 description 2
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 description 2
- 239000002915 spent fuel radioactive waste Substances 0.000 description 2
- PMTRSEDNJGMXLN-UHFFFAOYSA-N titanium zirconium Chemical compound [Ti].[Zr] PMTRSEDNJGMXLN-UHFFFAOYSA-N 0.000 description 2
- JFALSRSLKYAFGM-UHFFFAOYSA-N uranium(0) Chemical compound [U] JFALSRSLKYAFGM-UHFFFAOYSA-N 0.000 description 2
- 101150000971 SUS3 gene Proteins 0.000 description 1
- 230000005856 abnormality Effects 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000004992 fission Effects 0.000 description 1
- YPANPSDPZOVDOM-UHFFFAOYSA-N gold zirconium Chemical compound [Zr].[Au] YPANPSDPZOVDOM-UHFFFAOYSA-N 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- FGIUAXJPYTZDNR-UHFFFAOYSA-N potassium nitrate Chemical compound [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 description 1
- 235000010344 sodium nitrate Nutrition 0.000 description 1
- 239000004317 sodium nitrate Substances 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
本発明は、耐硝酸々化性の優れたジルコニウム基合金に
関するものである。DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a zirconium-based alloy with excellent nitric acid oxidation resistance.
［従来の技術］
硝酸溶液を取扱う化学プラント等に使用される耐食材料
としては、５ＵＳ３０４Ｌ、５ＵＳ３１０Ｌ等のステン
レス鋼が知られている。しかしながら上記ステンレス鋼
を耐食材料として用いた場合には、硝酸溶液の沸騰温度
或はそれに近い様な過酷な条件下では腐食を起こす。さ
らに、腐食により溶出するＦｅ（ＩＩＩ）イオンやＣｒ
（Ｖｌ）イオン等の酸化性イオンによっても粒界腐食は
助長される様であり、これに起因して液漏れ事故が度々
生じていた。そこでステンレス鋼よりも更に高い耐食性
を有すると期待されるジルコニウムの使用が考えられて
いる。[Prior Art] Stainless steels such as 5US304L and 5US310L are known as corrosion-resistant materials used in chemical plants and the like that handle nitric acid solutions. However, when the above-mentioned stainless steel is used as a corrosion-resistant material, corrosion occurs under severe conditions such as at or near the boiling temperature of the nitric acid solution. Furthermore, Fe(III) ions and Cr ions eluted by corrosion
Grain boundary corrosion seems to be promoted by oxidizing ions such as (Vl) ions, and liquid leakage accidents have frequently occurred due to this. Therefore, the use of zirconium, which is expected to have even higher corrosion resistance than stainless steel, is being considered.
しかしながら硝酸溶液中に酸化性物質が共存する様な環
境下では後述する様にジルコニウム金灰単体は耐食性を
発挿す限界があることが分かった。硝酸溶液を使用し、
更に酸化性物質が共存する様な環境としては、通常の硝
酸を取扱う化学工業以外に次に示す様な原子力産業での
利用がある。具体的には、原子力利用の再処理工業では
、原子力発電所で燃焼させた使用済燃料を沸騰硝酸で溶
解し、未使用のウランや新たに生成したプルトニウムを
回収することが中心的作業になっているが、この際、硝
酸溶液中にはウランやプルトニウム以外に核分裂生成物
や超ウラン元素が溶解しており、これらの元素の中には
非常に高い酸化還元電位を呈するものが存在する。例え
ば超ウラン元素の一つであるＡｍは、Ａｍ’十からＡｍ
”に還元されるとき１．９８ＶｖｓＡｇ／Ａｇ Ｃｆｌ
もの高い電位を示す。即ちＡｍなどが多量に溶解した使
用済核燃料再処理プロセスの環境は硝酸溶液であり且つ
高酸化性環境となる代表的な例である。However, in an environment where oxidizing substances coexist in the nitric acid solution, it has been found that there is a limit to the corrosion resistance of zirconium gold ash alone, as described below. using nitric acid solution,
Furthermore, as an environment where oxidizing substances coexist, in addition to the chemical industry that normally handles nitric acid, there are applications in the nuclear industry as shown below. Specifically, in the nuclear power reprocessing industry, the main task is to dissolve spent fuel burned in nuclear power plants with boiling nitric acid and recover unused uranium and newly generated plutonium. However, at this time, in addition to uranium and plutonium, fission products and transuranic elements are dissolved in the nitric acid solution, and some of these elements exhibit extremely high redox potentials. For example, Am, one of the transuranium elements, is from Am'0 to Am
” when reduced to 1.98V vs Ag/Ag Cfl
Shows extremely high potential. That is, the environment of the spent nuclear fuel reprocessing process in which a large amount of Am and the like are dissolved is a nitric acid solution and is a typical example of a highly oxidizing environment.
［発明が解決しようとする問題点コ
本発明者らの実験結果を示すことによって、問題点の所
在を明らかにする。[Problems to be Solved by the Invention] The problems to be solved will be clarified by showing the experimental results of the present inventors.
第２図は、沸騰硝酸（硝酸濃度ニア０％）中において５
ＵＳ３０４Ｌステンレス鋼及び純ジルコニウム（ＡＳＴ
Ｍ Ｒ６０７０２）の電気化学的測定を行なった結果
を示すグラフである。５ＵＳ３０４Ｌステンレス鋼を沸
騰硝酸中に浸漬したとき（図面中に破線で示す）には照
合電極（Ａｇ／ＡｇＣＪ２電極）に対して０．９３Ｖの
電位（これを腐食電位ＥＯと称する）を示すが、該腐食
電位ＥＯから電位を強制的にプラス側へ変位させると直
ちに急激な電流の立上がりが認められた。腐食電位Ｅｏ
から強制的に電位をプラス側に変位させることを陽分極
と称するが、陽分極を施すことは環境を酸化性に設定す
ることに外ならない。即ち第２図に示された現象は７０
％沸騰硝酸中で５ＵＳ３０４Ｌステンレス鋼が容易に腐
食されることを示すものである。Figure 2 shows 5% in boiling nitric acid (nitric acid concentration near 0%).
US304L stainless steel and pure zirconium (AST
2 is a graph showing the results of electrochemical measurement of MR60702). When 5US304L stainless steel is immersed in boiling nitric acid (indicated by a broken line in the drawing), it exhibits a potential of 0.93V (this is referred to as corrosion potential EO) with respect to the reference electrode (Ag/AgCJ2 electrode). As soon as the potential was forcibly shifted from the corrosion potential EO to the positive side, a rapid rise in current was observed. Corrosion potential Eo
Forcibly shifting the potential to the positive side is called anodic polarization, and applying anodic polarization is nothing but setting the environment to be oxidizing. That is, the phenomenon shown in Figure 2 is 70
% boiling nitric acid shows that 5US304L stainless steel is easily corroded.
一方５ＵＳ３０４Ｌステンレス鋼の場合と同様にして純
ジルコニウムの電気化学性測定を行なったところ、（図
面中に実線で示す）腐食電位ＥＯ自体はＳ Ｕ Ｓ ３
０４ Ｌノ場合と同様な値（０，９３ＶｖｓＡｇ／Ａｇ
Ｃｆ１）を示すが、該腐食電位ＥＯから陽分極させる
と一時的に電流が立上がるものの、電流が停滞する領域
（０，９５〜１．０６Ｖ ｖｓＡ ｇ／ＡｇＣｕ）が現
われる。この領域は所謂不働態領域であり、通常はとん
ど腐食しない領域である。On the other hand, when the electrochemical properties of pure zirconium were measured in the same manner as in the case of 5US304L stainless steel, the corrosion potential EO itself (shown as a solid line in the drawing) was SUS3.
04 Same value as L case (0.93VvsAg/Ag
Cf1), but when anodic polarization is performed from the corrosion potential EO, the current temporarily rises, but a region (0.95 to 1.06 V vs. A g/AgCu) where the current stagnates appears. This region is a so-called passive region, and is usually a region that hardly corrodes.
しかしながら更に１．０６ＶｖｓＡｇ／Ａｇ Ｃｆｌを
超えて陽分極させると、電流が急激に立上がり、ジルコ
ニウムが激しく腐食する現象が認められる。この現象は
、高電位下腐食と呼ばれるものである。このことは７０
％沸騰硝酸中において、ジルコニウムが１．０６Ｖ ｖ
ｓＡ ｇ／Ａ ｇ Ｃ１を超える高酸化性環境におかれ
たときに腐食することを示している。However, when anodic polarization is performed further exceeding 1.06 VvsAg/Ag Cfl, a phenomenon is observed in which the current rises rapidly and zirconium is severely corroded. This phenomenon is called high potential corrosion. This is 70
% boiling nitric acid, zirconium is 1.06V v
This indicates that corrosion occurs when placed in a highly oxidizing environment exceeding sA g/A g C1.
更に本発明者らは、上記高電位下腐食現０象か硝酸中の
みならず、硝酸ナトリウム（ＮａＮＯ２）、硝酸カリウ
ム（ＫＮＯ３）等の硝酸イオン（ＮＯ３−）を含む硝酸
溶液中でも生じることを見出した。その結果を第３図に
示す。Furthermore, the present inventors have discovered that the above-mentioned corrosion phenomenon under high potential occurs not only in nitric acid but also in nitric acid solutions containing nitrate ions (NO3-) such as sodium nitrate (NaNO2) and potassium nitrate (KNO3). . The results are shown in FIG.
即ち、４０％沸騰硝酸ナトリウム溶液、４０％沸騰硝酸
カリウム溶液に純ジルコニウム（ＡＳＴＭＲ６０７０２
）を浸漬して腐食電位から陽分極させると、４０％沸騰
硝酸の場合と全く同様に１．５ＶｖｓＡｇ／Ａｇ ｃｉ
から急激に電流の立上がりが認められ腐食を生じること
が分かった。尚第３図中には４０％沸騰硫酸中で純ジル
コニウムを陽分極させた時の結果を同時に示したが、硫
酸中では２、ＯＶｖｓＡｇ／Ａｇ ＣＩＬまで陽分極さ
せても電流の立上がりを示すことがなく、ジルコニウム
は良好な不働態状態が保持された。従って本発明の目的
は第２図、第３図に示した内容の趣旨から明らかな如く
、硝酸（又は硝酸溶液）中でしかも高酸化性環境となっ
ても耐食性に優れた効果を発揮するジルコニウム基合金
を提供する点に存在するものである。That is, pure zirconium (ASTMR60702
) and anodic polarization from the corrosion potential, 1.5V vs Ag/Ag ci, exactly the same as in the case of 40% boiling nitric acid.
A sudden rise in the current was observed, indicating that corrosion occurred. Figure 3 also shows the results when pure zirconium was anodically polarized in 40% boiling sulfuric acid, but in sulfuric acid, even when anodically polarized up to 2, OVvsAg/Ag CIL, the current rises. zirconium remained in a good passive state. Therefore, as is clear from the gist of the content shown in FIGS. 2 and 3, the object of the present invention is to use zirconium which exhibits excellent corrosion resistance even in nitric acid (or nitric acid solution) and even in a highly oxidizing environment. It exists in that it provides a base alloy.
［問題点を解決するための手段］
上記目的を達成し得た本発明の構成とは、チタンを０．
１〜５０重二％含有し、残部がジルコニウム及び不可避
不純物からなる点に要旨を有するものである。[Means for Solving the Problems] The structure of the present invention that achieves the above object is that titanium is made of 0.
The gist is that it contains 1 to 50% by weight, with the remainder consisting of zirconium and unavoidable impurities.
［作用］
本発明は、第２図及び第３図に示した如く、硝酸溶液中
においてジルコニウムが高酸化環境におかれると高電位
下腐食を起こすという事実を見出したことに端を発する
ものである。本発明と同様の構成を採用して純ジルコニ
ウムよりも耐食性を損なうことなく安価且つＨ曇化を意
図した技術は提案されているが（特公昭３３−５７０４
） 、 該技術は積極的に耐食性の向上を図ることを
目的としたものではなく、本発明は木質的に上記技術と
異なるものである。更に詳述すると、上記技術は塩酸又
は硫酸中において単純に浸漬したときの耐食性、即ち電
気化学的には腐食電位を示す領域での耐食性のみを考慮
しており、しかも硝酸中での耐食性には全く触れていな
いものである。[Function] As shown in FIGS. 2 and 3, the present invention originates from the discovery that when zirconium is placed in a highly oxidizing environment in a nitric acid solution, corrosion occurs at a high potential. be. A technique has been proposed that employs a structure similar to that of the present invention and is less expensive than pure zirconium without impairing its corrosion resistance and is intended to produce H clouding (Japanese Patent Publication No. 33-5704
), This technique is not aimed at actively improving corrosion resistance, and the present invention is different from the above technique in terms of wood quality. To explain in more detail, the above technology only considers corrosion resistance when simply immersed in hydrochloric acid or sulfuric acid, that is, corrosion resistance in a region that exhibits a corrosion potential electrochemically, and does not consider corrosion resistance in nitric acid. It has not been touched upon at all.
元来、熱力学的に活性な金属であるジルコニウムが、通
常の腐食環境で高耐食性を有するのはジルコニウム表面
に酸化皮膜を形成し、この酸化皮膜が高耐食性を有する
為とされている。又腐食電位（浸漬電位）から陽分極し
たとき、急激に電流が立上がる迄の比較的低電流密度の
領域の不働態状態においては酸化皮膜が安定に存在し、
このことによって高耐食性が保持できるものとされてい
る。Zirconium, which is originally a thermodynamically active metal, has high corrosion resistance in normal corrosive environments because it forms an oxide film on the surface of zirconium, and this oxide film has high corrosion resistance. In addition, when anodic polarization is performed from a corrosion potential (immersion potential), an oxide film stably exists in a passive state in a region of relatively low current density until the current suddenly rises.
It is said that this allows high corrosion resistance to be maintained.
従って第２図に示した様にジルコニウムの腐食電位（浸
漬電位）が約０．９３Ｖ ｖｓＡ ｇ／Ａ ｇ ＣＩＬ
であり、又１．０６ＶｖｓＡｇ／Ａｇ ＣｆＬを超える
電位で急激な電流の立上がりが認められたことは耐食性
を保持する不働態領域が約０．１３ （１，０６−０，
９３） Ｖの範囲内であり、その領域は余り広くない。Therefore, as shown in Figure 2, the corrosion potential (immersion potential) of zirconium is approximately 0.93V vs A g/A g CIL
Also, the fact that a sudden rise in current was observed at a potential exceeding 1.06V vs Ag/Ag CfL indicates that the passive region that maintains corrosion resistance is approximately 0.13 (1,06-0,
93) It is within the range of V, and the area is not very wide.
この結果、硝酸溶液中に強酸化性イオンが混入されるこ
となどにより容易に高酸化環境となり、ジルコニウムの
腐食を起こすものであると理解できる。As a result, it can be understood that strong oxidizing ions are mixed into the nitric acid solution, easily resulting in a highly oxidizing environment, which causes corrosion of zirconium.
本発明者らは上記事情に鑑みて鋭意研究した結果、通常
の不純物を含むジルコニウム例えばＡＳＴＭ Ｊ６０
７０２級ジルコニウムにチタンを適量添加することによ
って高電位下腐食発生電位が著しくプラス側に移行する
ことを見出し、本発明を完成するに至った。The present inventors conducted extensive research in view of the above circumstances, and found that zirconium containing ordinary impurities, such as ASTM J60
It was discovered that by adding an appropriate amount of titanium to 702 grade zirconium, the corrosion potential under high potential shifts significantly to the positive side, and the present invention was completed.
以下、図面を用いて本発明の作用を更に詳述する。第１
図はジルコニウムにチタンを各種割合（重量％）添加し
たジルコニウム基合金の陽分極曲線を示すグラフである
。第１図から明らかな様に、急激な電流の立上がりを示
す高電位下腐食発生電位はチタンの添加量が増加するに
従ってプラス側に移行しており、耐食性を有する不働態
領域が広がっていることが理解される。尚第１図の結果
を導くために使用した硝酸は、７０％硝酸を大気圧下で
沸騰させたものであり、このときの陽分極曲線電位走査
速度は５０Ｖ／ｍｊｎである。Hereinafter, the operation of the present invention will be explained in further detail using the drawings. 1st
The figure is a graph showing anodic polarization curves of zirconium-based alloys in which various proportions (wt%) of titanium are added to zirconium. As is clear from Figure 1, the corrosion potential under high potential, which indicates a rapid rise in current, shifts to the positive side as the amount of titanium added increases, indicating that the passive region with corrosion resistance is expanding. is understood. The nitric acid used to derive the results shown in FIG. 1 was 70% nitric acid boiled under atmospheric pressure, and the anodic polarization curve potential scanning rate at this time was 50 V/mjn.
次に本発明者らはジルコニウムにチタンを１重量％添加
したものを用い、この場合の沸騰硝酸濃度の影響を調査
した。その結果を第４図に示す。Next, the present inventors used zirconium with 1% by weight of titanium added and investigated the influence of the boiling nitric acid concentration in this case. The results are shown in FIG.
第４図から明らかな様に、高電位下腐食発生現象は硝酸
濃度に依存しているのが理解される。As is clear from FIG. 4, it is understood that the phenomenon of corrosion occurring under high potential depends on the nitric acid concentration.
ジルコニウムにチタンを添加することによって高電位下
腐食発生電位がプラス側に移行する理由は、詳細には不
明であるが恐らくジルコニウム基合金表面上の酸化皮膜
を強固にする為と思われる。The reason why the corrosion occurrence potential under high potential shifts to the positive side by adding titanium to zirconium is not clear in detail, but it is probably to strengthen the oxide film on the surface of the zirconium-based alloy.
チタンの添加量に関しては、０．１％未満であれば高電
位下腐食発生電位をプラス側に移行させる効果が乏しく
、少なくとも０．１％は必要である。Regarding the amount of titanium added, if it is less than 0.1%, the effect of shifting the corrosion occurrence potential under high potential to the positive side is poor, so at least 0.1% is necessary.
又ジルコニウム−チタン合金は全率固溶体であり、自由
に溶は合うので、ジルコニウム中へのチタンの最大添加
量は特に制限はなくチタンの含有量を任意に増減するこ
とができる。純ジルコニウムが硝酸中で呈する様な高電
位下腐食現象は、純チタンでは、２．ＯＶｖｓＡｇ／Ａ
ｇ Ｃｆｌもの高酸化環境であっても認められない。従
って耐酸化性に関する限りでは、ジルコニウム中へのチ
タンの添加量は０．１％以上であれば任意に設定するこ
とができる。しかしながらチタンの添加量が５０％を超
えるとジルコニウム−チタン合金の機械的強度が大きく
なりすぎ成型加工性が困難となるので、ジルコニウムの
特性を損なうことなく本発明の目的を達成するにはチタ
ン添加量の上限を５０％とするのが望ましい。本発明で
は、チタン添加量の範囲は０．１〜５０％に特定した。Furthermore, since the zirconium-titanium alloy is a wholly solid solution and is freely soluble, there is no particular restriction on the maximum amount of titanium added to zirconium, and the titanium content can be increased or decreased as desired. The corrosion phenomenon under high potential that pure zirconium exhibits in nitric acid is similar to that observed in pure titanium. OVvsAg/A
It is not recognized even in a highly oxidizing environment such as g Cfl. Therefore, as far as oxidation resistance is concerned, the amount of titanium added to zirconium can be set arbitrarily as long as it is 0.1% or more. However, if the amount of titanium added exceeds 50%, the mechanical strength of the zirconium-titanium alloy becomes too large and moldability becomes difficult. It is desirable that the upper limit of the amount be 50%. In the present invention, the range of the amount of titanium added is specified to be 0.1 to 50%.
［実施例コ
ジルコニウムにチタン０．１ 、０．５ 、 ２及び５
％（重量％）添加したジルコニウム基合金を溶製し、夫
々について沸騰７０％硝酸中にて１．Ｉ ＶｖｓＡｇ／
ＡｇＣｆ１の電位を印加して定電位電解を行なった。該
定電位電解を２４時間継続して行なっても電流値は１０
”−２ｍ Ａ ／ ｃｍ２程度であり、金属表面には全
く異常が認められなかった。[Example Cozirconium with titanium 0.1, 0.5, 2 and 5]
% (wt%) of zirconium-based alloys were melted, and each was heated in boiling 70% nitric acid for 1. I VvsAg/
Constant potential electrolysis was performed by applying a potential of AgCf1. Even if the constant potential electrolysis is continued for 24 hours, the current value is 10
It was approximately -2 mA/cm2, and no abnormality was observed on the metal surface.
比較例
ＡＳＴＭ Ｒ６０７０２級ジルコニウムについて沸騰
７０％硝酸中にて上記実施例と同様に、１、Ｉ Ｖｖｓ
Ａｇ／Ａｇ Ｃλの電位を印加し定電位電解を行なった
。その結果、電位を印加した直後から電流が急激に流れ
た。更に約３０秒後に試験片を取出して表面を観察した
ところ、該試験片は黒色に変色して腐食し、所々に孔食
が認められた。Comparative Example ASTM R6070 Grade 2 zirconium in boiling 70% nitric acid as in the above example.
A potential of Ag/Ag Cλ was applied to perform constant potential electrolysis. As a result, a current suddenly flowed immediately after the potential was applied. Further, after about 30 seconds, the test piece was taken out and the surface was observed. The test piece turned black and corroded, and pitting corrosion was observed in some places.
［発明の効果］
以上述べた如く本発明によれば、既述の構成を採用する
ことによって耐硝酸々化性に優れたジルコニウム基合金
が実現できた。[Effects of the Invention] As described above, according to the present invention, a zirconium-based alloy with excellent nitric acid oxidation resistance was realized by employing the above-described configuration.
第１図はジルコニウムにチタンを各種割合で添加したジ
ルコニウム基合金の陽分極曲線を示すグラフ、第２図は
沸騰硝酸中において５ＵＳ３０４Ｌステンレス鋼及び純
ジルコニウムの電気化学的測定を行なフた結果を示すグ
ラフ、第３図は純ジルコニウムを硝酸イオン（ＮＯ３−
）を含む各種硝酸溶液中に浸漬したときの陽分極曲線を
示すグラフ、第４図はジルコニウム基合金を各種濃度の
沸騰硝酸中に浸漬した場合の陽分極曲線を示すグラフで
ある。Figure 1 is a graph showing the positive polarization curves of zirconium-based alloys containing zirconium and titanium added in various proportions. Figure 2 shows the results of electrochemical measurements of 5US304L stainless steel and pure zirconium in boiling nitric acid. The graph shown in Figure 3 shows pure zirconium with nitrate ions (NO3-
), and FIG. 4 is a graph showing anodic polarization curves when zirconium-based alloys are immersed in various concentrations of boiling nitric acid.
Claims (1)
ム及び不可避不純物からなるものであることを特徴とす
る耐硝酸々化性に優れたジルコニウム基合金。A zirconium-based alloy with excellent oxidation resistance and oxidation resistance, characterized in that it contains 0.1 to 50% by weight of titanium, with the remainder consisting of zirconium and unavoidable impurities.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6379786A JPS62222037A (en) | 1986-03-20 | 1986-03-20 | Zirconium-base alloy excellent in resistance to oxidation by nitric acid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6379786A JPS62222037A (en) | 1986-03-20 | 1986-03-20 | Zirconium-base alloy excellent in resistance to oxidation by nitric acid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62222037A true JPS62222037A (en) | 1987-09-30 |
| JPH0545657B2 JPH0545657B2 (en) | 1993-07-09 |
Family
ID=13239727
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6379786A Granted JPS62222037A (en) | 1986-03-20 | 1986-03-20 | Zirconium-base alloy excellent in resistance to oxidation by nitric acid |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62222037A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02294446A (en) * | 1989-05-08 | 1990-12-05 | Sumitomo Metal Ind Ltd | Zirconium-base alloy having excellent stress corrosion cracking resistance |
| US5026521A (en) * | 1989-05-08 | 1991-06-25 | Sumitomo Metal Industries, Ltd. | Zirconium-titanium and/or tantalum oxygen alloy |
-
1986
- 1986-03-20 JP JP6379786A patent/JPS62222037A/en active Granted
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02294446A (en) * | 1989-05-08 | 1990-12-05 | Sumitomo Metal Ind Ltd | Zirconium-base alloy having excellent stress corrosion cracking resistance |
| US5026521A (en) * | 1989-05-08 | 1991-06-25 | Sumitomo Metal Industries, Ltd. | Zirconium-titanium and/or tantalum oxygen alloy |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0545657B2 (en) | 1993-07-09 |
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