(沈陽師范大學(xué)化學(xué)與生命科學(xué)學(xué)院，沈陽110034)
摘 要: 通過熱壓采用機(jī)械合金化(MA)法合成的合金粉末制備納米晶塊體Fe-60Ni-15Cr(MA)合金，并與粉末冶金(PM)法制備的常規(guī)尺寸Fe-60Ni-15Cr(PM)合金對(duì)比，研究兩種合金在700~900℃、0.1MPa純氧中的氧化行為以及晶粒細(xì)化對(duì)其氧化行為的影響。結(jié)果表明：Fe-60Ni-15Cr(PM)和Fe-60Ni-15Cr(MA)合金的氧化動(dòng)力學(xué)曲線均偏離拋物線規(guī)律。在相同溫度下，納米尺寸Fe-60Ni-15Cr(MA)合金的氧化速率明顯低于常規(guī)尺寸Fe-60Ni-15Cr(PM)合金的。Fe-60Ni-15Cr(PM)合金表面沒有形成保護(hù)性的Cr2O3膜，而是形成了由Fe的氧化物組成的外氧化膜和由Fe、Ni和Cr氧化物組成的內(nèi)層，并有合金和氧化物相組成的混合內(nèi)氧化形成。相反Fe-60Ni-15Cr(MA)合金表面則只形成了保護(hù)性的Cr2O3外氧化物膜。因此，晶粒細(xì)化有利于降低合金表面形成連續(xù)Cr2O3外氧化膜所需Cr的臨界含量，促使合金能在較低的Cr含量下形成連續(xù)有保護(hù)性的Cr2O3外氧化膜。
關(guān)鍵字: Fe-Ni-Cr合金；晶粒細(xì)化；納米晶；高溫氧化
（College of Chemistry and Life Science, Shenyang Normal University, Shenyang 110034, China）
Abstract:Nanocrystalline bulk Fe-60Ni-15Cr alloy was prepared by hot pressing alloyed powders synthesized by mechanical alloying (MA) method. High temperature oxidation behavior of the alloy was investigated at 700-900℃ in 0.1MPa pure oxygen，compared with the corresponding coarse grained Fe-60Ni-15Cr alloy prepared by powders metallurgy (PM) technique. The results show that the oxidation kinetics of Fe-60Ni-15Cr(PM) and Fe-60Ni-15Cr(MA) alloys deviate parabolic rate law. At the same temperatures, the oxidation rate of nanocrystalline Fe-60Ni-15Cr(MA) alloy is lower than that of coarse grained Fe-60Ni-15Cr(PM) alloy. Coarse grained Fe-60Ni-15Cr(PM) alloy is unable to form the continuous and protective scales of Cr2O3. In fact, the alloy forms the external Fe oxide scales followed by a layer composed by Fe, Ni and Cr oxides, and there is an internal oxidation in the alloy. On the contrary, nanocrystalline Fe-60Ni-15Cr(MA) alloy is able to form the continuous and protective scales of Cr2O3. It is oblivious that the grain refinement is able to decrease the critical Cr content which is required to form the continuous and protective scales of Cr2O3 and is helpful to form the continuous scales of Cr2O3 under Fe-Ni-Cr alloy surface.
Key words: Fe-Ni-Cr alloys; grain refinement; nanocrystalline; high temperature oxidation
