碳对镍基高温合金AM3热腐蚀性能的影响

为了更充分地了解碳对镍基高温合金热腐蚀性能的影响,提高合金的耐热腐蚀性能,本文研究了不同碳含量镍基高温合金AM3在850℃条件下,经75%Na2SO4+25%NaCl饱和混合盐溶液热腐蚀5 h的行为。利用扫描电镜(SEM)、X射线衍射(XRD)等测试方法分析了合金热腐蚀后的组织形貌和腐蚀产物。研究表明,腐蚀5 h过程中,碳含量(质量分数)为0、0.045%、0.15%的合金持续增重,碳含量为0.085%的合金在2~4 h发生氧化膜与盐膜的碱性熔融,有失重现象存在。合金加入碳后,促使合金表层腐蚀层变薄且与基体结合力变好。含碳的镍基高温合金腐蚀层产物以氧化物为主,主要有NiO、TiO2、Al2O3、Cr2O3。碳含量(质量分数)为0.085%、0.15%的合金由于腐蚀层氧化物较薄,可检测到Al4CrNi15、Ni3Al相的存在。综合分析发现碳含量为0.085%时,合金耐热腐蚀性能达到最优。

Effect of carbon on the hot corrosion of Ni-based superalloy AM3

In order to better understand the effect of carbon on the hot corrosion properties of nickel-based crystal superalloys and improve their hot-resistant corrosion properties,the behavior of Ni-based superalloy AM3 with different carbon(C)content was studied,which were sat in 75%Na2SO4+25%NaCl saturated mixed salt solution for 5 hours at 850℃.The topography of microstructure and corrosion products of the alloys were investigated by means of SEM,X-ray diffraction(XRD).Results show that during 5 hours of corrosion,the weight of alloys with C content of 0,0.045 and 0.15(wt%)increased continuously,while alkaline melting of oxide film and salt film occurred in the alloy with C content of 0.085(wt%)between the 2nd and the 4th hour,and weightlessness phenomenon also appeared.After adding C to the alloys,the corrosion layers of the alloys surface were thinned and the bonding force with the matrix became better.The corrosion layer products of carbon-containing nickel-base superalloy were mainly oxides,such as NiO,TiO2,Al2O3,and Cr2O3.Al4CrNi15 and Ni3Al phases could be detected in the alloys with C content of 0.085 and 0.15(wt%)due to their thinner oxide on the corrosion layer.When the C content was 0.085(wt%),the hot-resisting corrosion of the alloy were optimized.