Influence of Nickel Content and Oxidation Conditions on High-Temperature Oxidation Behavior of Steel with High Silicon

• Main Authors: Jun-hua Chang, 張君華
• Other Authors: Jaw-Min Chon
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/81476634321288195594

碩士 === 義守大學 === 材料科學與工程學系碩士班 === 93 === The oxidation behavior of 4 high Si-content steels ( containing 1.11 wt% Si ) with various amounts of Ni ( 0.01~0.40wt% ) was investigated in pure O2, air, and 99.9%N2 for 20 ~ 60 min at 1150℃. The roles of Ni-content and oxidation parameters (containing various atmospheres and durations of time) were studied. The results showed that the alloy heated at 1150℃in pure oxygen atmosphere, the thickness of the external oxide layer, the Si-enriched layer and the internal oxide layer decreased, but the depth of scale root increased with increasing duration of time. Yet, the diameter of internal fayalite in the oxide layer remained changed. For the alloy treated in the air atmosphere, the thickness of the external oxide layer, the Si-enriched layer and the internal oxide layer decreased as the oxidation period increased. In comparison with the alloy treated in pure oxygen, all the oxide layers produced in air were thicker. On the contrary, the size of fayalite in the internal oxide grew and the depth of scale root increased. As the alloy treated at 1150℃ in 99.9%N2, the oxidation behavior became slower in comparison with those in higher O2 atmospheres. The size and growing rate of the intergranular oxide increased with increasing oxygen content. When O2 content reached to 25%, fayalite would debond from the internal oxide layer. In addition, it was found that the conditions of Ni content inhibited the oxidation of the alloy in all atmospheres. The inhibition effect of Ni on oxidation in air appeared to increase as the wt% of Ni increased. This thesis has clearly demonstrated the mechanism of intergranular oxidation was reduced with the O2 content in atmosphere and Ni as the inhibition of oxidation played an important role for oxidation process in high silicon steel.