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2011-Sustainable Industrial Processing Summit
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| Editors: | Florian K |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2012 |
| Pages: | 630 pages |
| ISBN: | 978-0-9879917-2-0 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
Electrochemical Sinthesis Of Double Carbides Of Tungsten And Molybdenum Coatings From Tungstenate-molybdate-carbonate Melts On Metal And Nonmetallic (diamond) Surfaces
Marina Adamokova1; Hasbi Kushkhov1; Fatima Kuchmezova1; Ruzana Mamhegova1;1KABARDINO-BALKARIAN STATE UNIVERSITY, Nalchik, Russia;
Type of Paper: Regular
Id Paper: 123
Topic: 6
Abstract:
It is known that coatings of refractory metals and their carbides on metal and nonmetallic surfaces sharply increase firmness of materials and products to deterioration and corrosion.In the present work are presented results of investigation by electrochemical synthesis of double carbides of tungsten and molybdenum coatings on metal and nonmetallic surfaces in ionic melts at 1173 K. We investigated the influence of concentration of sodium tungstenate, sodium molybdate, lithium molybdate and lithium carbonate, the electrolysis temperature, the cathodic current density on process of joint electrosynthesis of double tungsten and molybdenum carbides on copper, nickel plates, and also natural diamonds crystals. Solid double carbide molybdenum (tungsten) deposits are obtained at 1173 K. At temperature more low 900°C powder deposits drop out. The investigation of influence current density on products of electrolysis was carried out in molten system Na2WO4 - Na2MoO4 - Li2MoO4 - Li2CO3 at temperature 1173 K. It was established that optimal values of current density is in an interval 0.05-0.1 А/cm2. At a current density more than 0.1 А/cm2 covering roughness decreases that is caused by considerable deterioration of its cohesion with surface. At a current density less than 0.05 А/cm2 speed of corrosion of a substrate exceeds speed of carbide deposition, therefore and the covering with good cohesion is impossible. Thus, the possibility of electrochemical synthesis of double tungsten (molybdenum) carbides is established. The thickness of double tungsten (molybdenum) carbides was in range 5-50 microns. The influence of temperature and electrolyte structure on double tungsten (molybdenum) carbides coatings on metal and nonmetallic (diamond) substrates were determinate for tungstenate-molybdate-carbonate melts.This work is carried out with support by the program FPP "Scientific and scientific-pedagogical personnel of innovative Russia" for 2009-2013 years.