Electrodeposition of molybdenum carbide from molten Salts

Abstract

The refractory carbides are characterized by their high melting points, high values of hardness, high tensile strength and chemical stability. Due to these remarkable properties they have a wide range of applications such as cutting and grinding tools, bearings, textile-machinery parts and oxidation-resistant gas burners. Metal carbide coatings are mainly used to improve the mechanical (wear resistance, strength and hardness) and chemical (corrosion and oxidation resistance) properties of metallic parts. The principal coating processes for refractory carbides are chemical-vapor deposition, physical-vapor deposition and thermal spray, but such coatings can also be obtained by electroplating. In the present work molybdenum carbide layers were electrodeposited from the LiF-NaF-KF eutectic melt containing K2CO3 and Na2MoO4 salts. The coatings were obtained by both direct and pulse electroplating processes. The influence of bath composition, temperature and electrical parameters of electrodeposition on the morphology of the deposits was studied using scanning electron microscopy. The composition of the coatings was determined by X-ray diffractometry. The nucleation mechanism of the molybdenum carbides was analyzed by chronoamperometry. © 2012 Nova Science Publishers, Inc. All rights reserved.