Protective oxide layers formed during electrochemical oxidation of hafnium carbide

• Published in: Powder metallurgy and metal ceramics Vol. 48; no. 9-10; pp. 595 - 599
• Main Authors: Lavrenko, V. A., Talash, V. N., Desmaison-Brut, M., Rudenko, Yu. B.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01-09-2009; Springer Nature B.V
• Subjects: Alloys; Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Composites; Corrosion resistance; Glass; Hafnium oxide; HFC; Materials Science; Metallic Materials; Nanomaterials; Nanostructure; Natural Materials; Oxides; Polarization; Powder metallurgy; Protective; Solid solutions; formation of protective nanofilm; hafnium oxycarbide; hafnium carbide; hafnium oxides; chemosorption; anodic oxidation
• ISSN: 1068-1302; 1573-9066
• DOI: 10.1007/s11106-010-9173-0

The composition of oxide nanofilm formed on the HfC anode under electrolysis of a 3% NaCl solution at potentials between – 0.20 and +1.90 V is studied using the potentiodynamic method of polarization curves and Auger electron spectroscopy and SEM methods. The film consists of the upper layer formed in polymolecular chemosorption of O
2
and Cl
2
gases followed by the HfO
2
+ C (1 : 1) layer. Two inner layers represent a 7 at.% O
2
solid solution in HfC and a mixture of HfC
0.7
O
0.3
and HfO (7 : 1). The oxide film 30–40 nm thick formed at potentials up to 1.35 V is protective and ensures very high corrosion resistance of HfC without any further polarization.