三种M3Al型金属间化合物的低温热腐蚀

Na_2SO_4沉积物显著地加速Fe_3Al、Ni_3Al和Ti_3Al在600℃模拟燃气气氛中的腐蚀.腐蚀产物为M与Al的氧化物和硫化物的混合物.Fe_3Al和Ti_3Al的耐蚀性优于Ni_3Al因为Fe_3Al腐蚀产物中有一含高Al_2O_3的内层在Ti_3Al上则有由TiO_2和NbO_2组成的中间层而Ni_3Al的腐蚀产物的内层含有大量硫化镍有利于Ni的向外传输Na_2SO_4中添加NaCl对三种M_3Al的腐蚀过程无明显影响     

Fe和两种工业钢在500℃含氯气氛中ZnCl2-KCl盐膜下的腐蚀

研究了纯Fe,NF616和SS304钢在500℃含氯气氛中ZnCl2-KCl盐膜下的腐蚀行为.结果表明,3种材料都发生了加速腐蚀,生成了较厚的氧化膜,且在氧化膜与基体金属之间出现了熔融状氯化物混合盐.此外,合金在此环境中的抗腐蚀性随其Cr含量的提高而显著提高,这是在腐蚀过程中氧化膜内层出现了Fe-Cr尖晶石或Cr2O3阻挡了金属离子快速向外扩散的结果.讨论了材料发生加速腐蚀的机制.     

Corrosion of Fe-15Ce alloy in three mixed-gas atmospheres

1　ＩＮＴＲＯＤＵＣＴＩＯＮＭｅｔａｌｌｉｃｍａｔｅｒｉａｌｓｆｏｒｈｉｇｈ ｔｅｍｐｅｒａｔｕｒｅａｐｐｌｉｃａ ｔｉｏｎｓｅｘｐｏｓｅｄｉｎｓｕｌｆｕｒａｎｄｏｘｙｇｅｎａｔｍｏｓｐｈｅｒｅｓ ,ｓｕｃｈａｓｔｈｏｓｅｐｒｅｖａｉｌｉｎｇｉｎｔｈｅｇａｓｃ     

2.25CrMo钢在还原性含氯气氛中的高温腐蚀行为

采用热重法及SEM／EDX，XRD研究了2．25CrMo钢在500和600℃下含氯还原性气氛中的腐蚀行为．结果表明，实验材料在两种温度下均发生了加速腐蚀，并且在外氧化膜／基体界面检测到了氯的存在．合金腐蚀动力学从500℃时的近似抛物线向600℃时的直线转变与氯化物在该温度下的蒸汽压有关．讨论了材料发生加速腐蚀的机制．     

机械合金化Ag-30Cr合金在0.1 Mpa纯氧气中的氧化

采用机械合金化方法制备了Cr含量为30％(质量分数)的两相颗粒极细的Ag—Cr合金，在700℃，800℃及0．1MPa纯氧气中氧化时，机械合金化Ag-30Cr合金外层为Ag层，其下方为复合氧化物AgCrO2，最内层为连续的Cr2O3，这一结构不同于粗晶粒粉末冶金Ag—Cr合金的复杂的混合氧化膜。这主要是由于晶粒的细化加快了Cr颗粒的溶解，加速了Cr从合金到膜的扩散，从而有效地促进Cr2O3层的形成。     

Effect of grain size on high-temperature oxidation behavior of Cu-80Ni alloy

1　INTRODUCTIONTheoxidationofunalloyedcopperandnickelhasalreadybeenstudiedindetail.Whilethehigh tem peratureoxidationofCu Nialloys ,alsostudiedanumberoftimestodate[13] ,isanexampleofarela tivelysimpleclassofscalingofbinaryalloysbyasin gleoxidant,becausethemetalsformacontinuousse riesofsolidsolutions ,whiletheiroxides ,CuO ,Cu2 OandNiO ,exhibitsmallmutualsolubilitiesandshowsignificantdifferencesinthethermodynamicstabilityandparabolicgrowthrates .Thus ,copper richalloysformexternalscales…     

在600-800℃低氧压下Co-Nb合金的氧化

研究了含15与30wt%Nb的两种Co-Nb合金在600-800℃低氧压F的氧化性能选择的氧压低于相应温度的氧化钴分解压,由H2-CO2混合气获得,在600℃为10-24atm,而700与800℃为10-20atm.两种合金在600与700℃氧化结果仅产生由α-CO与氧化铌(NbO2与Nb2O5)混合物组成的内氧化带在700℃尚可能生成双元氧化物CONb2O6在内氧化带界而无贫Nb层可见.两会金,尤其是Co-30Nb在800℃时发生了由内氧化向外氧化的转变,伴随有贫Nb的单相区出现于合金的表层.从Co中N     

Oxidation behavior of temary Fe- 15Cu-5Al and Fe-85Cu-5Al alloys in pure oxygen at 900℃

The oxidation of two two-phase ternary Fe-Cu-Al alloys containing about 5%（mole fraction） aluminium, one Fe-rich and one Cu-rich, has been studied at 900 ℃ in 1~105 Pa pure oxygen. The Fe-rich Fe-15Cu-5Al alloy presents two quasi-parabolic stages, with a large decrease of the parabolic rate constant after about 50min. The presence of 5% Al greatly reduces the oxidation rate of this alloy with respect to a binary Fe-Cu alloy of similar composition by forming an external protective Al203 layer, which is present near the scale/alloy interface. Due to the high stress-growth effect, this thin Al203 layer cannot completely prevent further oxidation of the alloy underneath. On the contrary, the Cu-rich Fe-85Cu-5Al alloy presents a single parabolic stage and forms a thick and porous external scale, coupled to the internal oxidation of Fe and Al. As a result, the oxidation of Cu-rich alloy at 900 ℃ is much faster than that of the Fe-rich alloy.     

NiCr合金在含氯氧化性气氛中的高温腐蚀

研究了纯Ni以及不同Cr含量的NiCr合金在5%O2-0.3%HCl-N2(体积分数)气氛中800℃的腐蚀行为,结果表明:在氧化膜/基体金属界面处有氯化物生成,合金的加速腐蚀机制为氯参与的"活化腐蚀"过程.NiCr合金在腐蚀初期表现为失重与生成Cr的氯化物和氯氧化物的挥发性有关,但Cr依然有益于合金的抗氯化-氧化腐蚀性.     

High temperature scaling of Ni-15Cu-5Al alloy in 1 × 105 Pa pure oxygen

The oxidation of the ternary alloy Ni-15Cu-5Al in 1 × 105 Pa pure oxygen at 700 ℃ and 800 ℃ was studied. The results show that the behavior of the Ni-rich alloy is similar to that of the binary Ni-Al alloy with the same Al content in the form of an external NiO layer coupled to the internal oxidation of aluminium. The presence of 15%(mole fraction) Cu cannot modify substantially the values of relevant parameters affecting the transition from the internal to the external oxidation of aluminium. The presence of 5 % Al reduces the oxidation rate of the corresponding Ni-Cu alloy during the whole oxidation stages, though 5 % Al is still insufficient to form protective external alumina scales.