Oxidation stability of boride coatings

Abstract

In this work, plain, low carbon steel S235JRG1 was boronized at 1273 K for 45-150 min by using a Durborid powder. The microstructure, phase constitution and oxidation behavior of the resulting boride layers have been investigated. Layers with an average thickness of 76-123 µm have been produced. The boride layer has a distinct tooth-like microstructure. It is composed of Fe2B and FeB in unequal amounts. The boride layer oxidation behavior has been investigated by a simultaneous thermal analysis in a flowing synthetic air at 873-1173 K for 21-24 h. A parabolic oxidation of the boride layer has been observed. The rate constants are found between 1.039 × 10 −9 to 3.781 × 10 −6 kg 2 m −4 s −1 , depending on temperature and oxidation time. The activation energy of oxidation at temperatures below 1173 K has been estimated to be 93 kJ mol −1 . At 1173 K, two successive parabolic periods have been found, followed by a breakaway oxidation behavior. The oxide scale of the boronized steel is composed of different iron oxides and iron borates. The oxidation mechanisms of boride coatings are discussed and implications towards high temperature stability are provided.K e y w o r d s : boronizing, high temperature oxidation, X-ray diffraction, thermogravimetric analysis

Experimental Investigation of Isothermal Section of the B-Cr-Fe Phase Diagram at 1353 K

“…The system is subsystem of various complex alloys, for example, modified ferritic steels for energy industry [1][2][3], steels for production abrasive, and corrosion-resistant components [4]. Information about the system is also important for study of boride coatings on various alloys and metals, including iron [5,6].…”

Solid-state Thermoelectric Characteristics of NiII, FeII, CoII, and CuII Borohydrides

“…On the other hand, metal borides (M-Bs) [26][27][28][29][30][31][32][33][34] and metal borohydrides (M-BHs) [35][36][37][38][39][40][41][42][43][44][45] of p-, d-, and f-block elements have become in the spotlight as solid-state materials.…”

“…Nevertheless, these two classes of materials are closely related where M-BHs undergo dehydrogenation to yield M-Bs when subjected to heat (300-400 °C) under an inert atmosphere [35][36][37][38]40]. These M-Bs are generally classified as boron-rich (MB12 -MB70) and metal-rich (M2B-to-M5B), exhibiting a variety of structures, including isolated B atoms, chains, layer, and clusters [26][27][28][29][30][31][32][33][34]. Currently, the exceptional structural, hardness and thermal properties of M-Bs receive increasing attention as hard refractory (TiB6), hard magnets (Nd2Fe14B), battery electrodes, conducting ceramics (ZrB2, HfB2), electro-catalysis, and superconducting (MgB2) materials [26][27][28][29][30][31][32][33][34].…”

Effect of Ekabor 2 powder on the mechanical properties of pure iron powder metal compacts

“…As result, FeB and Fe 2 B phases were seen on the boride layer. A parabolic oxidation of the boride layer has been observed (Ptacinova et al, 2015).…”

“…The last study which examined was done by Ptacinova et al (2015). In this study, plain, low carbon steel S235JRG1 was boronized at 1000 °C for 45 min -150 min by using a Durborid powder.…”