報告書番号

W93011

タイトル（和文）

ランタンクロマイトの機械強度と焼結機構

タイトル（英文）

MECHANICAL STRENGTH AND SINTERING MECHANISM OF LANTHANUM CHROMITES

概要 （図表や脚注は「報告書全文」に掲載しております）

ランタンクロマイトは，セパレータ材料として最も期待されている。平板型固体電解質燃料電池（ＳＯＦＣ）のセル構造上，セパレータ材はスタック中の強度材としての役割も求められる。ＳＯＦＣ作動温度１０００度の機械強度は，ＬａＣｒ０．９Ｍｇ０．１Ｏ３：１９．０ｋｇｆ／平方ｍｍ，Ｌａ０．９Ｃａ０．１ＣｒＯ３：３．７ｋｇｆ／平方ｍｍ，Ｌａ０．９Ｓｒ０．１ＣｒＯ３：７．９ｋｇｆ／平方ｍｍ，Ｌａ０．９Ｃａ０．１２ＣｒＯ３：３．７ｋｇｆ／平方ｍｍであった。難焼結性材料であるランタンクロマイトの機械強度は，焼結機構が密接に関係していると考えられる。

概要 （英文）

SOLID OXIDE FUEL CELLS (SOFC) HAVE HIGH POTENTIAL AS A NEW ELECTRIC POWER GENERATION SYSTEM. ONLY THE PLANAR CELL CONFIGURATION HAS HIGH EFFICIENCY,HIGH POWER DENSITY AND LOW PRODUCTION COST. IN PLANAR SOFCS,THE MOST SIGNIFICANT PROBLEM IS GENERATION OF THERMAL STRESS IN THE STACK. WE HAVE BEEN DESIGNING A SELF-SUPPORTED PLANAR SOFC STACK,WHERE THE SEPARATOR PROVIDES MECHANICAL STRENGTH. THE MECHANICAL STRENGTH AT THE SEPARATOR,ESPECIALLY AT OPERATING TEMPERATURES OF 1000 DEGREE,IS QUITE IMPORTANT. THE MECHANICAL STRENGTH AND SINTERINGMECHANISM FOR ALKALINE-EARTH DOPED LANTHANUM CHROMITES HAS BEEN INVESTIGATED. THE THREE-POINT BENDING STRENGTH AT 1000 DEGREE WAS 19.0 KGF/SQUARE MM FOR LACR0.9MG0.1O3,3.7 KGF/SQUARE MM FOR LA0.9CA0.1CRO3,7.9 KGF/SQUARE MM FOR LA0.9SR0.1CRO3 AND 3.7 KGF/SQUARE MM FOR LA0.9CA0.12CRO3. THE SINTERING MECHANISM AND MECHANICAL STRENGTH OF DOPED LANTHANUM CHROMITES ARE RELATED AS FOLLOWS: 1.THE HIGHEST MECHANICAL STRENGTH OF LACR0.9MG0.1O3 WAS CAUSED BY THE LARGE SURFACE ENERGY OF THE SMALL GRAINSRESULTING THE SOLID-STATE SINTERING MECHANISM. 2.LANTHANUM CALCIUM CHROMITES SHOWED THE POOR MECHANICAL STRENGTH BECAUSE ANOMALOUS GRAIN GROWTH OCCURRED IN LIQUID-PHASE SINTERING. 3.THE MECHANICAL STRENGTH OF LA0.9SR0.1CRO3 WAS HIGHER THAT OF LANTHANUM CALCIUM CHROMITES ALTHOUGH DENSIFICATION WAS CAUSED BY LIQUID-PHASE SINTERING. THIS MAY BE BECAUSE SINTERING IS PARTLY PROMOTED BY THE FORMATION OF SMALL LIQUID PHASES CONTAINING STRONTIUM AND CHROMIUM.

報告者

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