(中南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410083)
摘 要: 通過(guò)真空鑄造得到Ni-10%Fe-10%Al-10%Cu(質(zhì)量分?jǐn)?shù))及分別添加0.8%Y、5.3%Ta和13.6%Cr(質(zhì)量分?jǐn)?shù))的Ni-Fe-Al-Cu-X(X：Y或Ta或Cr)4種合金，采用熔鹽腐蝕實(shí)驗(yàn)及SEM，XRD及EDX測(cè)試研究各合金在850 ℃靜態(tài)冰晶石熔鹽氣氛中的腐蝕行為。結(jié)果表明：在850 ℃冰晶石熔鹽氣氛中，Ni-10%Fe-10%Al-10%Cu合金表面形成的氧化物保護(hù)膜；由于氧的聚集、擴(kuò)散，并在熔鹽/氧化膜界面處發(fā)生O2+2e=2O2−還原反應(yīng)，而生成的O2−與MeO反應(yīng)生成MeO22−，致使NiO和Al2O3等氧化物層疏松、多孔、易剝落；另外，氧化物保護(hù)膜也被熔鹽揮發(fā)的氟化物通過(guò)物理化學(xué)作用而溶解，形成坑洞，腐蝕層呈現(xiàn)層疊狀；添加0.8%Y和5.3%Ta可凈化合金晶界，使腐蝕層中氧化產(chǎn)物更致密，提高合金抗冰晶石熔鹽氣氛腐蝕性能；添加13.6%Cr的Ni-10%Fe-10%Al-10%Cu合金，其腐蝕層形成Cr2O3及NiCr2O4冰晶石結(jié)構(gòu)的化合物，降低其他氧化物的活度，提高氧化膜的保護(hù)作用，該合金抗冰晶石熔鹽氣氛腐蝕性能最好。
關(guān)鍵字: Ni-Fe-Al-Cu合金；冰晶石熔鹽氣氛；Y；Ta；Cr
中圖分類(lèi)號(hào)：TG 146.15 文獻(xiàn)標(biāo)志碼：A
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The static thermal corrosion behaviors at 850℃ in cryolite melten atmosphere by adding 0.8%Y, 5.3%Ta and 13.6%Cr (mass fraction), respectively, in Ni-10%Fe-10%Al-10%Cu cast alloys were investigated by SEM, XRD and EDX. The results indicate that, the oxides layer is formed on the surface of Ni-10%Fe-10%Al-10%Cu (mass fraction) alloy. The reductive reaction O2+2e=2O2− takes place on the interface between melt salt and oxides layers due to the concentration and diffusion of oxygen. The oxides layers as NiO and Al2O3 tend to be loose, porous and easy to be peeled off because of MeO22− produced by the reaction between O2− and MeO. In addition, the oxide layers on the surface of Ni-10%Fe-10%Al-10%Cu alloy can easily be dissolved by fluoride volatized from molten salt after physical and chemical reactions, then the corrosion products are laminated. Adding 0.8%Y and 5.3%Ta can clear the impurities at grain boundaries and densify the oxides in the corrosion layer, thus the high temperature corrosion resistance of alloys in cryolite melten atmosphere is improved. The Ni-10%Fe-10%Al-10%Cu alloy with adding 13.6%Cr has the best corrosion resistance in cryolite melten atmosphere because the main oxides in corrosion layer are Cr2O3 and NiCr2O4, which can inhibit the activities of the other oxides and enhance the protective ability of the oxide layers.
Key words: Ni-Fe-Al-Cu alloy; cryolite melten atmosphere; Y; Ta; Cr
