摘要
采用DTA、XRD、SEM和EDX研究K282合金在700℃、800℃和900℃大气环境下氧化动力学行为。结果表明,700℃氧化时,氧化初期增重速度较快,之后增重速度变慢,材料只发生了外氧化,氧化层产物为Cr_2O_3。在800℃和900℃氧化时,合金的氧化增重遵循抛物线规律,合金发生了内氧化,内氧化产物为Al_2O_3,外氧化层产物为Cr_2O_3和TiO_2。合金氧化速率由金属离子和氧离子在氧化膜中的扩散速度决定,温度越高扩散速度越快,合金氧化增重速度越快。
High temperature oxidation behaviors of cast K282 alloy at 700℃ 800℃ and 900℃ in air environment are investigated by DTA,XRD,SEM and EDX.The results show that there is a faster gain weight rate at the initial oxidation stage,and it becomes slow subsequently at 700℃.And there is only external oxide scale composed of Cr_2O_3.The oxidation kinetic curves of K282 obey the parabolic law at 800 and 900℃.The internal oxidation of the alloy occurred and internal oxide Al_2O_3 was formed at 800℃ and 900℃,and the external oxide scale is composed of Cr_2O_3 and TiO_2.Gain weight rate depends on the diffusion speed of metal ion and oxygen ion.The diffusion speed increases with the increasing of temperature,causing a faster gain weight rate.
引文
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