Rare earth application for heat-resisting alloys  

作　　者：Tadaaki Amano 

机构地区：[1]Department of Materials Science and Engineering,Shonan Institute of Technology

出　　处：《Journal of Rare Earths》2010年第S1期12-21,共10页稀土学报（英文版）

基　　金：Project supported by the Grant-in-Aid for Scientific Research (20560679),Japan

摘　　要：High-temperature oxidation resistance of Al2O3-and Cr2O3-forming heat-resisting alloys with rare earths(yttrium-implanted FeCrAl,-added FeCrAl,-added FeCrAlPt alloys,Y2O3-or CeO2-coated NiCrSi,yttrium-or lutetium-added NiCr and NiCrSi) was studied in oxygen at high temperatures,by mass gain measurements,mass change measurements,amount of spalled oxide,observation of surface appearance,X-ray diffraction(XRD),scanning electron microscopy(SEM),electron probe X-ray microanalysis(EPMA) and transmission electron microscopy(TEM).After oxidation at 1573 K for 18 ks in oxygen,oxide scale on FeCrAl alloy spalled from the entire surface,however,yttrium-implanted FeCrAl alloys showed good oxide adherence.After oxidation at 1473 K for 18 ks in oxygen,mass gain of FeCrAlY alloys decreased with increasing yttrium of up to 0.1 wt.% follwed by an increase with the yttrium content,and the mass gain of FeCrAl0.005Pt0.05Y alloy with appropriate additions of platinum and yttrium was lower than that of FeCrAl0.1Y alloy.Yttrium-added FeCrAl alloys showed good oxide adherence.TEM analysis revealed that the alumina/alloy interface of FeCrAl0.005Pt0.05Y alloy showed good coherency.The scale surface of FeCrAl alloy was rough,however,those of FeCrAlY and FeCrAlPtY alloys were smooth.Cyclic oxidation of NiCrSi,Y2O3-or CeO2-coated NiCrSi alloys was studied up to 10 cycles(1 cycle:300 s) at 1523 K in oxygen.Mass change of NiCrSi alloy increased up to 3 cycles and then decreased up to 10 cycles because of oxide spallation during cooling.On the other hand,mass change of Y2O3-or CeO2-coated NiCrSi alloy increased up to 10 cycles,and these alloys showed good oxide adherence.Granular Cr2O3 particles on Y2O3-coated NiCrSi alloy were in size smaller than these on CeO2-coated NiCrSi alloy.This result suggested that oxidation rate of Y2O3-coated NiCrSi alloy was lower than that of CeO2-coated NiCrSi alloy.After oxidation at 1473 and 1573 K for 18 ks in oxygen,mass gain of yttrium-or lutetium-added NiCr and NiCrSi alloys decreased.Oxide scales on NiCrSiHigh-temperature oxidation resistance of Al2O3-and Cr2O3-forming heat-resisting alloys with rare earths(yttrium-implanted FeCrAl,-added FeCrAl,-added FeCrAlPt alloys,Y2O3-or CeO2-coated NiCrSi,yttrium-or lutetium-added NiCr and NiCrSi) was studied in oxygen at high temperatures,by mass gain measurements,mass change measurements,amount of spalled oxide,observation of surface appearance,X-ray diffraction(XRD),scanning electron microscopy(SEM),electron probe X-ray microanalysis(EPMA) and transmission electron microscopy(TEM).After oxidation at 1573 K for 18 ks in oxygen,oxide scale on FeCrAl alloy spalled from the entire surface,however,yttrium-implanted FeCrAl alloys showed good oxide adherence.After oxidation at 1473 K for 18 ks in oxygen,mass gain of FeCrAlY alloys decreased with increasing yttrium of up to 0.1 wt.% follwed by an increase with the yttrium content,and the mass gain of FeCrAl0.005Pt0.05Y alloy with appropriate additions of platinum and yttrium was lower than that of FeCrAl0.1Y alloy.Yttrium-added FeCrAl alloys showed good oxide adherence.TEM analysis revealed that the alumina/alloy interface of FeCrAl0.005Pt0.05Y alloy showed good coherency.The scale surface of FeCrAl alloy was rough,however,those of FeCrAlY and FeCrAlPtY alloys were smooth.Cyclic oxidation of NiCrSi,Y2O3-or CeO2-coated NiCrSi alloys was studied up to 10 cycles(1 cycle:300 s) at 1523 K in oxygen.Mass change of NiCrSi alloy increased up to 3 cycles and then decreased up to 10 cycles because of oxide spallation during cooling.On the other hand,mass change of Y2O3-or CeO2-coated NiCrSi alloy increased up to 10 cycles,and these alloys showed good oxide adherence.Granular Cr2O3 particles on Y2O3-coated NiCrSi alloy were in size smaller than these on CeO2-coated NiCrSi alloy.This result suggested that oxidation rate of Y2O3-coated NiCrSi alloy was lower than that of CeO2-coated NiCrSi alloy.After oxidation at 1473 and 1573 K for 18 ks in oxygen,mass gain of yttrium-or lutetium-added NiCr and NiCrSi alloys decreased.Oxide scales on NiCrSi

关 键 词：ALUMINA CHROMIA oxide adherence high-temperature oxidation rare earths 

分 类 号：TG146.45[一般工业技术—材料科学与工程]