報告書番号

T97060

タイトル（和文）

有機金属化学蒸着法によるステンレス鋼の耐食性向上技術の開発（その１）各種複合酸化皮膜の形成およびＢＷＲ模擬環境下での安定性評価

タイトル（英文）

IMPROVEMENT OF CORROSION RESISTANCE OF TYPE 304 STAINLESS STEEL BY MOCVD (PART 1) PREPARATION OF COMPOSITE OXIDE FILMS AND THEIR STABILITY UNDER SIMULATED BWR WATER CONDITIONS

概要 （図表や脚注は「報告書全文」に掲載しております）

有機金属化学蒸着（ＭＯＣＶＤ）法を用い，各種組成の異なる酸化皮膜をステンレス鋼表面に形成した。またＢＷＲ環境を模擬した高温水中における各種皮膜の安定性および耐食性を評価し以下の結果を得た。（１）ＭＯＣＶＤ法による皮膜の形成ＭＯＣＶＤ法により形成した，鉄，クロムおよびニッケルを含む種々の複合酸化皮膜は水蒸気酸化皮膜に比べ欠陥面積率が小さいことが明らかとなった。（２）ＢＷＲ模擬環境下での安定性評価・ニッケル／鉄複合酸化皮膜に覆われたステンレス鋼の耐腐食性は，表面処理を施していないステンレス鋼よりも優れていた。・Ｘ線回折の結果，ニッケル／鉄複合酸化皮膜は主にＮｉＦｅ２０４のスピネル構造を有しており，腐食試験前後で形態の変化は認められなかった。以上の結果よりＭＯＣＶＤ法により作製したニッケル／鉄複合酸化皮膜は，熱力学的に安定で，欠陥の少ないＮｉＦｅ２０４構造を有していることより，ＢＷＲ環境条件下ではステンレス鋼の耐食性を向上させるとの結論を得た。

概要 （英文）

IN RECENT YEARS, THE PROGRESS OF SURFACE COATING TECHNIQUES, SUCH AS PHYSICAL VAPOR DEPOSITION (PVD) AND CHEMICAL VAPOR DEPOSITION (CVD), HAS ENABLED THE FORMATION OF HIGHLY PROTECTIVE FILMS ON MATERIALS. THESE FILMS IMPROVE THE CORROSION AND ABRASION RESISTANCE OF MATERIALS. IT IS EXPECTED THAT THE CORROSION OF COMPONENT MATERIALS OF POWER PLANTS WILL BE SUPPRESSED, AND THE ACCUMULATION OF RADIOACTIVE CORROSION PRODUCTS WILL BE PREVENTED, BY THE FORMATION OF HIGHLYPROTECTIVE FILMS ON SUCH COMPONENT MATERIALS. THE DEVELOPMENT OF SURFACE COATING TECHNIQUES TO IMPROVE THE CORROSION RESISTANCE OF MATERIALS AND THE EVALUATION OF FILM PROPERTIES ARE THEREFORE DESIRED. IN THIS STUDY, COMPOSITE OXIDE FILMS WERE FORMED ON TYPE 304 STAINLESS STEEL BY METAL ORGANIC CHEMICAL VAPOR DEPOSITION (MOCVD). THE STABILITY AND CORROSION RESISTANCE OF THE OXIDE FILMS UNDER SIMULATED BWR WATER CONDITIONSWERE EVALUATED. THE MAIN RESULTS WERE AS FOLLOWS: 1.PREPARATION OF OXIDE FILMS BY MOCVD THE NUMBER OF DEFECTS IN FE, CR, AND NI COMPOSITE OXIDE FILMS PREPARED BY MOCVD WAS LESS THAN THAT IN FILMS PREPARED BY OXIDATION IN STEAM. 2.ESTIMATION OF FILM STABILITY UNDER SIMULATED BWR WATER CONDITIONS (1) THE CORROSION RESISTANCE OF STAINLESS STEEL COATED WITH NI/FE COMPOSITE OXIDE FILM WAS HIGHER THAN THAT OF UNCOATED STEEL. (2) THE NI/FE COMPOSITE OXIDE FILM PREPARED BY MOCVD WAS MAINLY COMPOSED OF NIFE204. X-RAY DIFFRACTION STUDY SHOWED THAT NO CHANGE IN FILM MORPHOLOGY RESULTED FROM THE CORROSION TEST. THESE RESULTS INDICATE THAT NI/FE COMPOSITE OXIDE FILM IS COMPOSED OF THERMODYNAMICALLY STABLE NIFE204WITH FEW DEFECTS AND THAT THIS FILM IMPROVES THE CORROSION RESISTANCE OF TYPE 304 STAINLESS STEEL UNDER SIMULATED BWR WATER CONDITIONS.

報告者

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