High temperature oxidation behavior of FeCo‐based nanocrystalline alloys

Abstract

This paper describes the dynamic and isothermal oxidation behavior of three different FeCo-based Fe 38.5 Co 38.5 Nb 7 Cu 1 B 15 , Fe 36-Co 36 Nb 7 Si 10 B 11 and Fe 33.5 Co 33.5 Nb 7 Si 15 B 11 alloys and one traditional FINEMET Fe 73 Nb 3 Cu 1 Si 15.5 B 7.5 alloy. Dynamic and isothermal oxidation measurements in controlled oxidizing atmosphere were performed and the oxidation apparent energy as well as the oxidation behavior was obtained. SEM observations were carried out in order to characterize the oxide layer formed during the oxidation measurements. The apparent activation oxidation energy found for the Fe 36 Co 36 Nb 7 Si 10 B 11 , Fe 33.5 Co 33.5 Nb 7 Si 15 B 11 and Fe 73 Nb 3 Cu 1 Si 15.5 B 7.5 alloys was about 35 kJ/mol and for the Fe 38.5-Co 38.5 Nb 7 Cu 1 B 15 alloy was about 70 kJ/mol.

Oxidation Resistance of Nanocrystalline Alloys

“…Improved oxidation resistance of FeBSi [87], Ni-based alloys [88][89][90][91][92][93], Zr and its alloys [40][41][42][43], Cr-33Nb [94], Fe-Co based alloys [95,96] and Cu-Ni-Cr alloys [97] is reported in their nanocrystalline form (in comparison to their microcrystalline counterparts). The mechanistic role of a nanocrystalline structure leading to the improved oxidation resistance is discussed below:…”

Electromagnetic Property Modulation of Flaky Ferromagnetic 304 Stainless-Steel Powders for Microwave Absorption at Elevated Temperatures

“…The coating of magnetic elements such as Co [26] and Ni [27] can reduce the influence of coating materials on the permeability of absorbents. However, the decomposition or oxidation of coating materials, as well as the difficulties in preparing dense coatings with pores smaller than oxygen molecules [28][29][30], hinders the long-term service of magnetic metallic absorbents at elevated temperatures.…”