摘要
藉H2—CO2混合气体获得低氧压,在600℃为1.01×10(-4)fPa,而700℃与800℃为1.01fPa,并研究含Nb为150与300mg/g的两种Ni-Nb合金在上述条件下的氧化行为实验结果显示,在600℃与700℃,两种合金仅发生内氧化,其组成为α-Ni与氧化铌(Nb_2O_5或/和NbO_2)通常,在紧挨内氧化带前沿的合金中并没有观察到发生贫Nb现象.与之不同,在800℃氧化的两种合金均产生连续的由氧化铌组成的外氧化膜而没有内氧化现象.从Nb在Ni中低溶解度的特点出发讨论了合金的氧化机制.
The oxidation of two Ni-Nb alloys containing 150 and 300 mg / g Nb has been studied at 600 -800℃ in H2 mixture providing an oxygen pressure of 1.01×10 ̄(-4)fPa at 600℃ and 1 .01 fPa O2 at 700 and 800℃,which are always below the dissociation pressure of Ni oxide. The scale formed on both alloys at 600 and 700℃ show only a region of internal oxidation composed of a mixture of a-Ni and Nb2O5 or NbO2,which formed from both the metal phases present, i.e.Ni8Nb and Ni3Nb. Only small or even no Nb depletion was observed in the alloys close to the front of the internal oxidation zone at these temperatures. On the contrary,samples of both alloys oxidized at 800℃ produced a continuous external scale of niobium oxides without internal oxidation.The oxidation mechanism of these alloys is examined with special reference to the effect of the low solubility of Nb in Ni.
出处
《材料研究学报》
EI
CAS
CSCD
1996年第3期246-252,共7页
Chinese Journal of Materials Research
关键词
高温
氧化
镍铅合金
Ni-Nb alloys high temperature oxidation