Kinetics inversion in isothermal oxidation of uncoated WC-based carbides between 450 and 800 °C

被引：98

作者：

del Campo, L. ^{[1
]}

Perez-Saez, R. B. ^{[1
,2
]}

Gonzalez-Fernandez, L. ^{[1
]}

Tello, M. J. ^{[1
,2
]}

机构：

[1] Univ Basque Country, Fac Ciencia & Tecnol, Dept Fis Mat Condensada, Leioa 48940, Bizkaia, Spain

[2] Univ Basque Country, Inst Sintesis & Estudio Mat, E-48080 Bilbao, Spain

来源：

CORROSION SCIENCE | 2009年 / 51卷 / 04期

关键词：

Hard metals; Infrared emissivity; High temperature corrosion; Kinetic parameters; Oxidation; HIGH-TEMPERATURE OXIDATION; STRENGTH DEGRADATION; CEMENTED CARBIDES; BEHAVIOR; HARD;

D O I：

10.1016/j.corsci.2008.12.022

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Oxidation of uncoated WC-based carbides (hard metals) has been investigated between 450 and 800 degrees C. An anomalous change in the oxidation behaviour has been found in the temperature range between 528 and 630 degrees C. Instead of the normal increase of the oxidation rates when the temperature increases, a kinetics inversion is produced: an anomalous decrease of the oxidation rates has been observed in this temperature range. Furthermore, this anomalous behaviour produces an important change in the activation energy. At temperatures below the anomaly (below 528 degrees C), an activation energy of 119 +/- 8 kJ/mol has been found, whereas above the anomaly (above 630 degrees C), an activation energy of 208 +/- 8 kJ/moI has been found. This anomalous temperature dependence of the oxidation behaviour can be related to a higher amount of complex oxide CoWO4 formed on the oxide scale, and to the effect that this oxide produces in the oxidation kinetics of the other oxides. (C) 2009 Elsevier Ltd. All rights reserved.

引用

页码：707 / 712

页数：6

共 18 条

[1] Strength degradation of a tungsten carbide-cobalt composite at elevated temperatures [J].