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局部腐食の事例解析に見る防食管理上の問題点

熊田誠

材料
1995年 44 巻 506 号 1308-1313
発行日: 1995/11/15
公開日: 2009/06/03

DOI https://doi.org/10.2472/jsms.44.1308

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Analysis of localized corrosion failures shows that troubles caused by materials, design and fabrication are a few, while those caused by operation occurr freqently over 50% of the total failures. Some of them probably develop social anxiety and may cause serious disaster such as explosion, fires and death. In this report, a yearly change of number of failures in complex up to 1988 is analyzed and problems associated with the troubles caused by localized corrosion are discussed from the viewpoint of corrosion control.
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インヒビターによるCr-Mo鋳鋼の清水中腐食疲労防止効果に及ぼすすき間の影響

三浦健蔵, 熊田誠, 大井利継

材料
1985年 34 巻 379 号 429-435
発行日: 1985/04/15
公開日: 2009/07/09

DOI https://doi.org/10.2472/jsms.34.429

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Corrosion tests were carried out in fresh water containing sodium nitrite inhibitor at 80°C using a Cr-Mo cast steel specimen and a specimen with a crevice which had been introduced artificially. The characteristics of corrosion inhibition of sodium nitrite inhibitor were then investigated. Fatigue tests were carried out in fresh water containing sodium nitrite inhibitor at 80°C using a relatively large specimen with a crevice. The effect of crevice on corrosion fatigue prevention was then investigated. The results obtained were as follows. The critical concentration of sodium nitrite inhibitor required for corrosion inhibition of Cr-Mo cast steel was found to be 1000ppm. Even though sodium nitrite inhibitor was added above the critical concentration level, crevice corrosion occurred on the specimen with a crevice. The specimen had a clear fatigue limit in air or in fresh water containing sodium nitrite inhibitor over the critical concentration level. The fatigue strength of the specimen with a crevice became markedly low due to the crevice corrosion. Corrosion fatigue cracks initiated from corrosion pits caused by crevice corrosion. Crevice corrosion also occurred in the crack propagation area near the crack initiation site, because hardly any fresh water was able to flow on to the crack surface due to obstruction by the O-ring bound to the specimen. On the initial crack propagation area where crevice corrosion occurred, striation was not clear and partial intergranular fracture was observed. Ductile patterns were predominant on the subsequent crack propagation area.
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Cu・Mo 添加鋳放しパーライト系球状黒鉛鋳鉄の耐食性

山本成, 小野修二, 福田正勝

鋳物
1993年 65 巻 9 号 712-717
発行日: 1993/09/25
公開日: 2011/06/22

DOI https://doi.org/10.11279/imono.65.9_712

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The authors investigated corrosion resistance and corrosion fatigue strength in city water of as-cast Cu-Mo added pearlitic Ductile Cast Iron (DCI). Results are summarized as follows : (1) The corrosion resistance of as-cast pearlitic DCI tends to be sensitive to obstacle ion, as compared with carbon steel casting. (2) Provided that cooling water contains max 50 ppm as S0₄^-- and max 100 ppm as Cl^-, inhibiter has to be added 6000 ppm ∼ 8000 ppm, in order to keep most superior corrosion resistance of as-cast pearlitic DCI. (3) In above (2) condition, if inhibiter is added over 6000 ppm, the corrosion fatigue strength of as-cast pearlitic DCI exceeds that of carbon steel casting, and recovers to fatigue strength of as-cast pearlitic DCI in air.
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オルガノポリシラン.合成と反応

熊田誠

日本化學雜誌
1969年 90 巻 5 号 425-444
発行日: 1969/05/10
公開日: 2011/05/30

DOI https://doi.org/10.1246/nikkashi1948.90.5_425

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メチルクロルシランの直接合成法で副産する高沸点残留物のなかに多量のジシラン化合物("`ジシラン留分")が含有されることの発見は,従来オルガノポリシランの化学の発展を阻んでいた原料問題を大幅に解決し,以来この分野の化学,とくにメチルポリシランの化学は飛躍的な発展をとげた。本論文では前半で,このジシラン留分を主原料とするケイ素官能性ならびに炭素官能性オルガノポリシランおよびペルメチルポリシランの合成法を述べ,後半において,こうしてえられるオルガノボリシランの種々の試薬および条件のもとにおける反応を,できうるかぎり機構論の立場から記述する。オルガノポリシランは対応する炭化水素およびその誘導体としばしば非常に異なり,種々の条件下で切断,不均化,あるいは分子内転位を受ける。またこれらの反応性は,ケイ素上の置換基の性質によって強く影響されることが多い。ケイ素一ケイ素結合の切断反応は形式的に炭素-炭素二重結合への親電子的付加反応に類似することがいくつかの例によって示される。
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清水中における軟鋼およびCr-Mo鋳鋼の腐食疲労とインヒビターによる防食効果

三浦健蔵, 熊田誠, 大井利継

材料
1982年 31 巻 340 号 64-69
発行日: 1982/01/15
公開日: 2009/06/03

DOI https://doi.org/10.2472/jsms.31.64

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In order to prevent corrosion damage, at present, corrosion inhibitor is added to the engine cooling water, as fatigue cracks appear on the surface of the water side of the cylinder cover in marine diesel engines. In the present study, rotating bending fatigue tests were carried out in fresh water similar to actual environments, and the damage from corrosion fatigue on the surface of the surface of the specimens, as well as the effect of the corrosion inhibitor in preventing corrosion fatigue were examined.
The S-N curves or S-T curves in fresh water levelled off but they began to descend again. It was found that the damage due to corrosion fatigue appeared distinctly over a long period even if the stress amplitude was low, and many corrosion pits and microcracks existed besides the main crack. A linear relation was obtained experimentally between the term (k-1) and the term (1/f_p), where k is the corrosion effect and f_p is the pitting factor. On the other hand, the corrosion fatigue strength in fresh water became equal to or greater than that in air when a sufficient amount of corrosion inhibitor over the critical concentration required for corrosion inhibition was added.
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ステンレス鋼の高温水中臭化物応力腐食割れ

熊田誠

Zairyo-to-Kankyo
1996年 45 巻 5 号 284-291
発行日: 1996/05/15
公開日: 2009/11/25

DOI https://doi.org/10.3323/jcorr1991.45.284

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Bromide stress corrosion cracking (Br^- SCC) of stainless steels has not been clear, owing to many unknown factors, however troubles caused by it have been reported in MSF desalination plant. In this study, environmental factors, materials and surface treatments of noble metals plating have been investigated in order to protect Br^- SCC in bromide containing high temperature water. SCC tests have been conducted by using slit-welded type specimens. The results are summaried as follows: (1) Concentration of disolved oxygen must be kept below 0.1ppm for protection of Br^- SCC. (2) Transgranular SCC due to pitting occurs in SUS 304 and SUS 316 stainless steels above 50ppm Br^- concentration. (3) The number of SCC is more major in Cl^- environment than in Br^- one above 0.5ppm disolved oxygen concentration. (4) Occurrence percentage of growing SCC is much higher in Br^- environment than in Cl^- one in all disolved oxygen concentration. This fact shows that Br^- SCC, especially in chemical plants, grows so large that contents leak. (5) Hastelloy C 276 is most completely resistant materials in heavily severe Br^- environment. (6) Only Rh in noble matal platings is the most effective to resistantly protect Br^- SCC. But the reason has not been clear in this study.
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Cr-Mo鋳鋼の清水中疲労強度に及ぼす表面仕上げの影響およびインヒビターによる腐食疲労防止効果

三浦健蔵, 熊田誠, 大井利継

材料
1984年 33 巻 375 号 1506-1512
発行日: 1984/12/15
公開日: 2009/06/03

DOI https://doi.org/10.2472/jsms.33.1506

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The effect of surface condition on fatigue strength, corrosion fatigue prevention and the corrosion fatigue damage which occurred in the specimen were investigated in fresh water and aqueous solution containing sodium nitrite inhibitor at 80°C using relatively large Cr-Mo cast steel specimens.
A finely machined specimen (surface roughness, R<2s), a roughly machined specimen (R≅20s) and a shot blusted cast skin specimen had a clear fatigue limit in air. The fatigue limit of the roughly machined specimen fell to about 90% of that of the finely machined specimen, but the fatigue limit of the shot blusted cast skin specimen became very high compared with those of the finely and the roughly machined specimens. The fatigue strengths of the finely and the roughly machined specimens in fresh water at 80°C were the same level. Many corrosion pits and microcracks occurred on both the finely and the roughly machined specimens. The shape of microcracks was semielliptical when the stress amplitude was relatively high, but the microcracks were combined with each other and were stretched along the surface of the specimen when the stress amplitude was low. The fatigue strengths of the finely and the roughly machined specimens in aqueous solution containing. sodium nitrite inhibitor at 80°C had the same level of fatigue limit as those in air, and corrosion pits and microcracks were not observed. On the other hand, the behavior of the fatigue strength of the shot blusted cast skin specimen in fresh water and aqueous solution containing sodium nitrite inhibitor at 80°C was different from that of the machined specimens.
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重畳応力下におけるCr-Mo鋳鋼の疲労破面の観察

三浦健蔵, 熊田誠

材料
1985年 34 巻 382 号 803-808
発行日: 1985/07/15
公開日: 2009/06/03

DOI https://doi.org/10.2472/jsms.34.803

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Fatigue crack propagation behavior and the corrosion inhibition effect of sodium nitrite inhibitior were investigated from the observation of fracture surface of Cr-Mo cast steel under superposed stress both in air and in fresh water containing NaNO₂ at 80°C.
Under zero-tention loading of single wave, the change of crack front profile, a/c (aspect ratio) and the relation between the crack growth rate, da/dN and stress intensity factor, ΔK were represented by the following equations.
a/c=0.90-3.98×10^-1(a/D), D: Diameter of specimen.
da/dN=1.04×10^-10(ΔK)^4.06
Beach mark spacings coincided well with the block of superposed waves, Z_p, and they were affected by the stress ratio, m. The beach marks were observed clearly at m=0.3, but not m=0.4 nor 0.5. The change of crack front profile was classified into two types. One was that where the crack propagated with a≅c in a semi-circular or semi-elliptical form. The other was that where the crack propagated with a<c, and afterwards propagated in a semi-elliptical form. The initial cracks always propagated with a<c in fresh water containing NaNO₂ at 80°C. The fracture patterns influenced by corrosion were observed at the initial crack propagation region.
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海中電着工法の電着技術に関する実験的研究 : その2 非金属体への応用

清水五郎

日本建築学会構造系論文集
1997年 62 巻 499 号 163-168
発行日: 1997/09/30
公開日: 2017/02/02

DOI https://doi.org/10.3130/aijs.62.163

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Application of electrodeposition techniques was extended over nonmetallic materials. A plastics mesh coated with a silver-copper conductive paint was proven to have an equivalent cathodic performance with that of galvanized iron meshes. A wire mesh embedded mortar was also tested, and the average deposition rate of 0.86 kg/A-hrm^2 was obtained. Electric properties of mortar and the calculation method of necessary voltages were presented. A preliminary experiment of space-filling deposition technique using gravel specimen implied a possibility of submerged prepacked concrete. These results confirm the feasibility and applicability of this technique.
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亜硝酸塩系インヒビターの分解挙動について

三浦健蔵, 熊田誠, 三宅良昭, 大井利継

防食技術
1980年 29 巻 8 号 392-396
発行日: 1980/08/15
公開日: 2009/10/30

DOI https://doi.org/10.3323/jcorr1974.29.8_392

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Decomposition behavior of sodium nitrite, which has been added to the circulating cooling water system of marine diesel engines as a corrosion inhibitor for steel, was investigated in 50ppm SO₄^2- ion solutions. In the absence of steel, no loss of sodium nitrite was observed in any case. When the sodium nitrite over the critical concentration required for corrosion inhibition was added, it was stable without decomposition and high inhibitive effect was observed. On the other hand, when the sodium nitrite was added below the critical concentration, the rate of decomposition was accelerated with decrease of ratio of the solution volume to the specimen area, and simultaneously pH of solution became high markedly and NH₄⁺ ion was detected. The decomposition of sodium nitrite, which forms NH₃ as the reduction product, may proceed as follows:
NO₂^-+5H₂O+6e^-→NH₃+7OH^-
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有機ケイ素化学の最近の進歩

熊田誠

高分子
1968年 17 巻 9 号 828-837
発行日: 1968/09/01
公開日: 2011/09/21

DOI https://doi.org/10.1295/kobunshi.17.828

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シリコーンという言葉が人の口にのぼってからすでに25年になる。この有機・無機の混血ポリマーはデビュー当時,それまでの有機ポリマーにみられない数多くのユニークな性能をそなえたため,「魔法の砂」の異名をさえもって迎えられた。したがって有機ケイ素といえばシリコーンそのものであるかのごとく思われがちだが,シリコーンの出現と発展に刺激されて,シリコーン以外の有機ケイ素化合物の化学が,この間に飛躍的な進歩を遂げたことをも見逃してはならない。周期律表におけるケイ素と炭素の相対的位置に基く両元素の化合物の構造や性質の違い,これが20世紀初頭の化学者の興味をひいた素朴なテーマであるが,次元こそ高度化はしたものの,規在の有機ケイ素化学者は再びこれと取り組みつつある。本稿はこの現状の一端の紹介である。
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沖縄海域における電着構造物の製造とその応用

山里清, 中村英雄, 友利昭之介, 熊田誠, 宮崎芳明, 佐々木晴敏

水産土木
1987年 23 巻 2 号 21-24
発行日: 1987年
公開日: 2018/11/30

DOI https://doi.org/10.18903/fishengold.23.2_21

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2-エチルヘキシルメタクリレート+ケトン系の相互拡散係数の測定と推算

小渕茂寿, 藤村健司, 横澤則忠, 熊田誠, 荒井康彦

熱物性
2000年 14 巻 1 号 73-80
発行日: 2000/01/31
公開日: 2009/05/25

DOI https://doi.org/10.2963/jjtp.14.73

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石英スプリングによる収着実験装置を用いて，2-エチルヘキシルメタクリレート十ケトン(アセトン，メチルエチルケトン，メチルプロピルケトン)系の相互拡散係数を，40℃，50℃にて，質量分率0.01～0.19の濃度範囲で測定し，自由体積理論による推算を試みた．測定されたすべての系に対して，相互拡散係数は濃度に依存し，濃度の増加とともに単調に増加することがわかった．また，推算に必要とされるパラメータを溶媒の物性値より見積もる前報での方法により求め，相互拡散係数の推算を試みた結果，10％以内の平均誤差で良好に表現することができた．
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化学モノグラフ 17 概説有機金属の化学(Organometallic Chemistry), P.L.Pauson著,
熊田誠
訳, A5判, 206頁, 800円, 化学同人

山川浩司

ファルマシア
1969年 5 巻 6 号 429-
発行日: 1969/06/15
公開日: 2018/08/26

DOI https://doi.org/10.14894/faruawpsj.5.6_429

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有機金属化学の本(ブックガイド)

山崎博史

ファルマシア
1976年 12 巻 3 号 215-216
発行日: 1976/03/01
公開日: 2018/08/26

DOI https://doi.org/10.14894/faruawpsj.12.3_215

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化学プラントにおける局部腐食問題と対策の実例

熊田誠

防食技術
1981年 30 巻 6 号 344-348
発行日: 1981/06/15
公開日: 2009/10/30

DOI https://doi.org/10.3323/jcorr1974.30.6_344

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Classification of the case histories of 965 encountered for last eleven years made clear that more than 30% of failures were caused by corrosion and that 98% of those were owing to localized corrosion such as pitting and stress corrosion cracking. Localized corrosion failures often results in considerable economic loss and disaster. This paper describes a few cases of localized corrosion and preventive studies which were conducted in order to improve structure, material and environment.
The first case is pitting corrosion of a stainless steel strainer in the purification plant of waste water using active carbon. Active carbon promoted the occurrence of pitting corrosion. The design modification of structure and cleaning of the strainer was employed as a countermeasure.
The second case is stress corrosion cracking which originated from corrosion pits under small deposits in a reactor made of austenitic stainless steel. From the results of plant tests, material of the reactor was changed from austenitic stainless steels to titanium. The third case is stress corrosion cracking which occurred around weld zone of SUS 316L in a distillation plant. The same material was used for the new fabricated plant, while stress corrosion cracking was prevented by solution heat treatment using large furnace.
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無機高分子材料について

大河原六郎

高分子
1962年 11 巻 9 号 650-653
発行日: 1962/08/20
公開日: 2011/09/21

DOI https://doi.org/10.1295/kobunshi.11.650

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微生物腐食を応用した金属の微細加工に関する研究

9K培地及び鉄酸化細菌の培養溶液中における鉄鋼及び銅の電気化学的測定と表面生成皮膜の観察

熊田誠, 小渕茂寿, 川角哲也, 堀内典子, 宇野義幸, 山田隆裕, 前田秀治, 幸英昭

Zairyo-to-Kankyo
2001年 50 巻 9 号 418-423
発行日: 2001/09/15
公開日: 2011/12/15

DOI https://doi.org/10.3323/jcorr1991.50.418

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The biomachining mechanism of metals for mild steel and copper has been investigated both by electrochemical measurements in 9K medium and ferrous oxidizing bacteria-cultured solution and by observations of the surface film. The results are as follows: (1) In all tested pH, passivation was found at near -450mV vs. SCE on the anodic polarization curves of mild steel in 9K medium. Great passivation was found also in the region of -500 to 0mV vs. SCE on the anodic polarization curves of copper. (2) Cathodic polarization curves of mild steel depolarized greatly in the region of -750 to -900mV vs. SCE in the bacteria-cultured solution. This depolarization caused by the reduction reaction of Fe³⁺+e→Fe²⁺accelerated the dissolution of metals. (3) Passivation was not found on the anodic polarization curves of mild steel in the bacteria-cultured solution. Natural electrode potential of copper in the bacteria-cultured solution shifted to the noble dirrection of -30 to +50mV vs. SCE. Passivation was not found also on the anodic polarization curves of copper. (4) Passivation at near -450mV vs. SCE in 9K medium seemed to be caused by the formation of FeSO₄ film from the results of EPMA of Fe and S. This film formation was remarkable on copper. (5) In 9K medium the dissolution of mild steel and copper was prevented by FeSO₄ film, however, in the bacteria-cultured solution FeSO₄ film was not formed owing to the action of bacteria and the dissolution was accelerated by oxidizing effect of Fe³⁺. (6) The biomachining mechanism of metals for mild steel and copper seemed to be as follows. Fe₂ (SO₄)₃ which was formed by the culture of bacteria accelerated the dissolution of both mild steel and copper as the oxidizing agent. The dissolution progressed as the two following reactions.
Fe₂(SO₄)₃+Fe→3FeSO₄ Fe₂(SO₄)₃+Cu→CuSO₄+2FeSO₄
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清水中におけるCr-Mo鋳鋼の腐食疲労に及ぼす繰返し速度の影響

三浦健蔵, 熊田誠, 大井利継

材料
1984年 33 巻 369 号 692-696
発行日: 1984/06/15
公開日: 2009/06/03

DOI https://doi.org/10.2472/jsms.33.692

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The effect of frequency on the fatigue strength and patterns of fracture surfaces of Cr-Mo cast steel were investigated in fresh water and also in water Containing sodium nitrite inhibitor at 88°C.
The fatigue strength in fresh water at 88°C had no fatigue limit and became markedly low at low frequency, 170cpm, in the long term tests. The fatigue strength in fresh water containing sodium nitrite inhibitor had no effect on frequency and had the same level of fatigue limit as that in air. In the long term tests, it was found that sodium nitrite inhibitor was stable and was effective for the inhibition of corrosion fatigue failure at any frequency. Fracture surfaces in fresh water were of an intergranular pattern in the crack initiation area, and of a plain and brittle pattern in the crack propagation area. However, the effect of frequency on patterns of fracture surfaces was not clear. Intergranular facets were partially observed in the crack initiation area, and ductile striations were observed clearly in the crack propagation area on fracture surfaces in fresh water containing inhibitor, which were of the same patterns as those in air. From the observation of fracture surfaces, it was found that sodium nitrite inhibitor was very effective for the inhibition of corrosion fatigue failure.
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櫻井英樹先生に文化功労者の顕彰櫻井英樹

吉良満夫

有機合成化学協会誌
2008年 66 巻 1 号 3
発行日: 2008/01/01
公開日: 2010/06/28

DOI https://doi.org/10.5059/yukigoseikyokaishi.66.3

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