Oxidation Kinetics of Boronized Low Carbon Steel AISI 1018

Abstract

The high-temperature oxidation behavior of boron coating on plain lowcarbon steel AISI 1018 was studied at 500, 600, 700, 800 and 900°C in air. The oxidation resistance of unboronized (uncoated) and boronized (boron-coated) specimens was studied isothermally in a thermogravimetric analyzer. The oxidation-rate constant represented as a parabolic rate constant (k p ) was evaluated with the parabolic rate law. The activation energy of oxidation on unboronized and boronized steel specimens was determined by Arrhenius law. Optical microscopy, XRD and SEM were used for surface characterizations. The experimental results show that boronized coating increases the oxidation resistance of plain low carbon steel AISI 1018 about five times and prevents oxygen from penetrating into the steel substrate at temperatures below 900°C.

Oxidation stability of boride coatings

“…For boronized steel, the oxidation resistance was higher compared to unboronized steel [27][28][29][30]. The superior oxidation resistance is mainly attributed to the formation of different iron borates and boron oxide scales, respectively [27][28][29].…”

“…As for 773-873 K, an amorphous B 2 O 3 was observed, forming a glassy layer on the coating surface [27]. B 2 O 3 has a low oxygen diffusion coefficient thereby acting as an effective oxidation barrier [27]. At 983-1073 K, the formation of iron borate was observed [27].…”

“…The oxidation kinetics of boronized steel has been recently investigated by Suwattananont and Petrova [27]. For boronized steel, the oxidation resistance was higher compared to unboronized steel [27][28][29][30].…”

“…The superior oxidation resistance is mainly attributed to the formation of different iron borates and boron oxide scales, respectively [27][28][29]. As for 773-873 K, an amorphous B 2 O 3 was observed, forming a glassy layer on the coating surface [27]. B 2 O 3 has a low oxygen diffusion coefficient thereby acting as an effective oxidation barrier [27].…”

“…B 2 O 3 has a low oxygen diffusion coefficient thereby acting as an effective oxidation barrier [27]. At 983-1073 K, the formation of iron borate was observed [27]. A severe oxidation of iron boride layers at 1173 K has been reported [27], however, the underlying activation mechanisms have not yet been examined.…”