三种β-NiAl相材料的短期热腐蚀行为比较研究

在Ni-30Al(mass%,下同)和Ni-20Cr-10Al铸态合金上进行粉末包埋渗铝,分别得到纯β-NiAl相涂层和β-(Ni,Cr)Al相涂层.在这两种渗铝试样和铸态Ni-20Cr-13Al合金(含β-NiAl、γ′-Ni3Al、α-Cr相)上涂覆了硫酸钠薄膜,进行900℃热腐蚀测试.经过10小时热腐蚀测试后,三种试样表面均生成Al2O3膜.腐蚀动力学分析表明,Cr对提高材料的抗热腐蚀性能是有益的;Ni-20Cr-10Al渗铝涂层试样的增重最低,仅为铸态Ni-20Cr-13Al合金试样增重的80%左右,Ni-30Al渗铝涂层试样增重的50%左右.

A Comparative Study on Short Term Hot Corrosion Behavior of Three β-NiAl Phase Materials

    Hot corrosion behavior of three β-NiAl phase materials,namely aluminized Ni-30Al(mass%)and Ni-20Cr-10Al,and a bare cast alloy Ni-20Cr-13Al,was studied.The aluminized layer of Ni-30Al was simple β-NiAl,and the aluminized layer of Ni-20Cr-10Al consisted of β-(Ni,Cr)Al,and the cast Ni-20Cr-13Al consisted of β-NiAl,γ′-Ni₃Al and α-Cr.The specimens were coated by Na₂SO₄ films,and tested in air at 900℃ for 10 h.After tests,only alumina scales were detected on the surfaces of all the specimens.The kinetic curves of the hot corrosion tests demonstrated that Cr is beneficial to the hot corrosion resistance of the β-NiAl phase materials.The mass gain of the aluminized Ni-20Cr-10Al was 20% lower than that of the cast Ni-20Cr-13Al, and was as half as that of the aluminized Ni-30Al.