Refractory Metals in Molten Salts Their Chemistry, Electrochemistry and Technology NATO ASISeries Advanced ScienceInstituteSeries A SeriespresentingtheresultsofactivitiessponsoredbytheNATOScienceCommittee, whichaimsatthedisseminationofadvancedscientificandtechnologicalknowledge, witha viewtostrengtheninglinksbetweenscientificcommunities. 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NATo-PCo-DATABASE Theelectronic indextotheNATO ASISeriesprovides fullbibliographical references (with keywords and/orabstracts)toabout50,000contributionsfrominternationalscientistspublishedinallsectionsof theNATOASISeries.AccesstotheNATD-PCO-DATABASEispossibleviaaCD-ROM"NATOScience andTechnology Disk" withuser-friendly retrieval software in English, French, andGerman (©WTV GmbHandDATAWARETechnologies,Inc.1989).TheCD-ROMcontainstheAGARDAerospaceData base. TheCD-ROMcanbeorderedthroughanymemberoftheBoardofPublishersorthrough NATD-PCO, Overijse,Belgium. 3.HighTechnology- Vol.53 Refractory Metals in Molten Salts Their Chemistry, Electrochemistry and Technology edited by David H. Kerridge Departmentof Engineering Materials, Universityof Southampton, Southampton, United Kingdom and Evgeny G. Polyakov Institute ofChemistry, KolaScience Centre, Russian Academy of Sciences, Apatity,Russia Springer-Science+Business Media, B.V. ProceedingsoftheNATOAdvancedResearchWorkshopon RefractoryMetalsinMoltenSalts Apatity,Russia August12-17,1997 AC.!.P.Catalogue recordtorthisbookisavailabletromthe LibraryotCongress. Printedonacid-freepaper AllRightsReserved ISBN 978-90-481-5054-0 ISBN 978-94-015-9135-5 (eBook) DOI 10.1007/978-94-015-9135-5 ©1998 SpringerScience+BusinessMediaDordrecht OriginallypublishedbyKluwerAcademicPublishers in 1998. Softcoverreprintofthehardcover 1stedition 1998 No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechanical, including photo copying,recordingorbyany informationstorageandretrievalsystem,without written permissionfromthecopyrightowner. TABLEOFCONTENTS Preface IX Logo ofthe ApatityARW xi Organising Committee xiii Papers (in orderofpresentation): 1. ThermodynamicsofNiobiumChloridesand Mixtures with Alkali Chlorides . M Gaune-Escard 2. Interrelationbetweenthe Composition and StructureofMetaphosphate PolyhedraofMolybdenumand Tungsten inthe CaseofElectro- deposition ofMetalsand theirAlloys 9 NI. Buryak, VA. BandurandS V Volkov 3. High PerformanceCoatingofSteel withTantalumBoride Layers 17 H. VettersandJ Christensen 4. Electrochemicaland UV-Visible SpectroscopicStudies ofRefractory Metals inChlorideMelts 31 J Bouteillon,JC.Gabriel,T Galvez, TR.Griffiths,P.Koronaios, JC Poignet,D. VincentandD. Vulpescu 5. High Temperature93NbNMR StudyofLiquid NbClsand its Mixtures with Various AlkaliChlorides 43 E. Schellkes,M Holzand W. Freyland 6. ElectrochemistryofRefractory Metals:Hf, Mo, Cr 61 N Adhoum, L.Arurault,J Bouteillon,A. Cotarta,JC Gabrieland JC Poignet 7. Deposition ofTitanium,Zirconiumand Hafnium DiborideCoatings by High-Temperature Electrochemical Synthesis from Chloro- Fluoride Melts 73 S V Devyatkin, G.Kaptay, VI. Shapoval,I.V Zarutskii, VP. Lugovoi andSA.Kuznetsov 8. The SynthesisofBorides,Carbidesand Silicides ofRefractoryMetals in Ionic-ElectronicMelts 81 NI. Shurov,A.J. Anfinogenov, VV Chebykin, L.P.Klevtsovand E.G.Kazanskii VI 9. PhysicochemicalPropertiesoftheMoltenSystem KF-KCl- KBF4 .K2TiF6 •• •••••• ••••• •••• •••• •••• •••••••••• •.. •• 87 M Chrenkrovd, V. Danek, A.SilnyandD.K.Nguyen 10. StudyofElectrodeProcessesinFLINAK-K2TaF7- KBF4Melt 103 I.P. Polyakova, E.G.Polyakov, G.A.Bukatova,A.A.Shevyryov, O.V. MakarovaandNJ Bjerrum II. TheCommonRegularitiesofEpitaxialGrowthofMonocrystalline MolybdenumandTungstenElectrodepositedfromMoltenSalts 109 NO Esina,A.M Molchanov, Z.I. ValeevandA.N Baraboshkin 12. TheElectrodepositionofAluminum-NiobiumAlloysfromChloro- alluminateElectrolytes 117 G.R.StaffordandG.M Haarberg 13. TechnologyofElectrodepositionfromMoltenSaltsforthePreparation ofElectrodeMaterialsBasedonRefractoryMetals 131 PierreTaxi!,B.Lafage, 0 Boiko,P.ChamelotandK. Serrano 14. NewCompounds [Nb (0, F)2].n[K).x(F,0)] (n=l,2,3) 403 ObtainedbyMoltenSaltsElectrolysis. PreparationandX-Ray DiffractionStudy 143 A.V. Arakcheeva, V.V. Grinevitch, E.G.PolyakovandSA.Kuznetsov 15. ElectrochemicalProcessesasaSumofChemicalEquations 153 V.G.Kremenetskiy 16. RoleoftheOxoacidityandLigandEffectintheElectrowinningof TitaniuminFusedSalts 159 F.Lantelme,A.BarhounandK. Kuroda 17. InfluenceofGaseousAtmosphereonAnodicProcessesofGlassy-Carbon andGoldElectrodesinNaCl-KCI-Na2C0 Melt 173 3 NM Barbin, V.N Necrasov, D.!.Terentiev andA.P.Pekar 18. MechanismofMolybdenumElectrodepositionfromMoltenSalts 183 A.Silny, V. DanekandM Chrenkova 19. ChemicalReactionsAccompanyingtheProcessesofRefractoryMetal Electrodeposition 189 S.A.Kuznetsov 20. ProductionofTantalumbyElectrolysisofOxohalide MeltwithOxide Anodes 197 Y.PZaikov, A.P.Khramov, V.P.Batukhtin, NN Chikhaleva,A.V. Frolov, I.E.Ivanovskiy,NG.Molchanova andN!. Moskalenko Vll 21. TantalumCurrentlessDeposition onNickel from Molten Salts 205 E Matychenko and V Novichkov 22. Electrochemical ProductionofHafnium-BasedCompositeMaterials 211 SA. Kuznetsov,S.V Kuznetsova,EG.Polyakovand P.T Stangrit 23. Rhenium Electrochemistry,Chemistryand Electrodeposition from Molten Salts 219 SA.Kuznetsov,A.B.Smirnov,A.N Shchetkovsky andAL Etenko 24. OxidationofNiobium inMolten Eutectic NaNOJ-KNOJ 227 VP. Yurkinski, EG. FirsovaandOA.Krasovitskaya 25. Evaluation ofHigh-Frequency SuperconductivityofNiobiumCoatings Prepared by Electrodeposition inMolten Salts 231 VN Kolosovand ES Matychenko 26. Evaluation ofHigh-Frequency SuperconductivityofNb.SnCoatings ObtainedbylointElectrochemical Deposition 239 VN Kolosov 27. The Oxidation ofAlloys Fe-Si-(Ta,Nb, W, Sn) bySodium and Calcium Sulphate Melts 245 S.A.Krasikov, VV Shulgin, VM. Chumarevand VP.Maryevich 28. The Electrochemical andThermodynamicCharacteristicsofChromium Complexesagainstthe BackgroundofLiCI-KCl and NaCI-KCl Melts accordingtothe LinearSweep Voltammetry Data 251 S.A. KuznetsovandP.T Stangrit 29. VoltammetricOxygenDetermination inMoltenFluorides 259 L.P.Polyakova, EG.Polyakov, G.A.BukatovaandN] Bjerrum 30. Tantalum Electrochemistry inChloride-Fluorideand Oxochloride- Fluoride Melts 263 L.P.Polyakova,Z.A.Kononova, VG.KremenetskyandEG.Polyakov SubjectIndex 269 Preface This NATO AdvancedResearchWorkshopwasdevoted toaspecializedtopic in molten salt chemistry and was held in an exotic location (as far as Westerners were concerned)well within the Arctic Circle. It neverthelessfacilitated afruitful week,both ofscience and ofhuman contacts. The 42 oral presentations and posters from nine countries enabled the 59 participants to learn a great deal about many areas ofrecent research in the molten salt chemistry of refractory metals, while making new contacts as well as renewing old friendships. Thetimeofinformal contact ledtothebeginningofanumberofnewresearch cooperationswith interchangeofpersonnel. Thus thetwinaimsofadvancingscienceand improving East-Westunderstandingwere bothamply fulfilled.Indeed awarm andhappy family atmosphere was very tangible doth during the scientific sessions and the social events,which participants, accompanyingpersons and localstaffallenjoyed. This opportunityofliving forashort timewithin theArctic Circle wasanovelty for most Westerners, who generallyappreciated the very warm weather(the hottest for 20yearsaccordingtosome residents),aswell asthe beautiful surroundingsofverygreen birch/pineforest,rushing rivers,vastlakesandroundedmountains,frequentlyilluminated bywonderfulsunsets. TheeveningbarbequebesideLakeImandra (100kmlong)andthe coach tour beside the beautiful White Sea dotted with islands in the Kandalaksha Recreational Area (National Park),to sample Pomor culture, dancing and fresh salmon soup,were high spots ofthe social programme. Scientificallythe Institute ofChemistry wasvisited forasummaryofitshistory,togetherwithtours ofthemoltensalt laboratories and plating workshop. Nevertobeforgotten wasthedriveuptothehugeopencastapatite mine atthe top ofKhibini mountain,when wewere enveloped inasnowstorm. Insummarythe ARWprovidedaverypositiveandworthwhileexperience,both scientifically and culturally, which will be long remembered bythose who took part. The presentvolumeofProceedings,containing the most significantofthe contributions totheARW,willdisseminatethescientificinformationmorewidelyandthusenhanceboth the benefit,and the circle ofthose who have benefitted, fromthis meeting. The Co-Directorsandalltheparticipantswishtothank mostwarmlytheScience Committee of NATO, together with the Assistant Secretary-General and Programme Director(Scientificand Environmental Affairs),who madetheARW possible,aswell as the following organisationswho supportedthe meeting financially. Russian Ministryfor ScienceandTechnology Russian Foundation for Basic Research Chepetsky MechanicalPlant Apatity Town Administration Danfoss A/S, Denmark Durand Ltd.,Guernsey David H.Kerridge Evgeny G.Polyakov Co-Directors,ARW IX LOGO OF THE APATITY ARW .NATO ADVANCED RESEARCH WORKSHOP· Z ~ > o ~ LRff?~tof~ Metals ~ I ; MoltfflSalts' ~ ? m ~ ~ ~ e An ATill Tbl ~ ~ x ~ ~ ~ ?\U9US1; 12th-17th 1997 ~ g APATITY· RUSSIA @ < 0 z ~ .NATO ADVANCED RESEARCH WORKSHOP~ The ear of wheat, copied from the large concrete sculpture marking arrival in the town, symbolises the importance of Apatity (founded 1966) as the home of the miners producing apatite ore from the top of the Khibini mountain . This ore, about 200 .106 tonne/annum at maximum output, is approximately 10% apatite, which is taken south by train and converted into superphosphate with sulphuric acid. This is an essential fertiliser for the wheatfields of central Russia.