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1 It -A A PULSED FIELD GRADIENT NUCLEAR MAGNETIC RESONANCE 1 SPECTROMETER FOR DIREC (U) NORTHWESTERN UNIV EVANSTON IL D H WHITMORE 24 APR 87 AFOSR-TR UNCLASSIFIED AFOSR F/G 7/4 NL U...,

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3 UNCLASSIFIED IT 1 g rp SECURITY CLASSFCA T ION OF -HIS OAGE AI lle. REPORT DOCUMENTATION PAGE Ia. REPORT SECU RITY CLASSIFICATION Ib RESTRICTIVE MARKINGS Unclassified 2.cf,,@iaTv ri &CtItIrATInhi hiitwnoity 3 DISTRIBUTION /AVAILABILITY OF REPORT 21 Approved for public release; Distribution unlimited MONITORING ORGANIZATION REPORT NUMBER(S2 AD-A AFosR.Thw 8 708?7 6. NAME OF PERFORMING ORGANIZATION 6b. OFFICE SYMBOL 7a NAME OF MONITORING ORGANIZATION X Northwestern University (fapibl) AFOSR/NC 6C. ADDRESS (City, State, and ZIP Code)?b ADDRESS (City, State, and ZIP Code) s- 619 Clark Street Evanston, Illinois Building Boiling 410 AFB, D.C _ S.. NAME OF FUNDING isponsoring Sb OFFICE SYMBOL 9 PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER ORGANIZATION (if applicable) AFOSR NC AFOSR SC. ADDRESS (City; State, and ZIP Code) 10 SOURCE OF FUNDING NUMBERS Building 410 PROGRAM PROJECT TASK IWORK UNIT Boiling AFB, D.C ELEMENT NO No 2917 NO A2 ACCESSION NO I1I TITLE (include Secunty Classificatia) A Pulsed Field Gradient Nuclear Magnetic Resonance Spectrometer for Direct Measurement of Ionic Diffusion in Solid Electrolytes. 12 PERSONAL AUTHOR(S) Whitmore, Donald Herbert 13a TYPE OF REPORT 13b. TIME COVERED 14 DATE OF REPORT (Year, M~onth, Day) S PAGE COUNT Final Technical Report IFROM T April 24, SUPPLEMENTARY NOTATION 17 COSATI CODES 18 SuBiECT TERMS (Continue on reverse of necessary and identify by block number) FIELD GROUP SUB-GROUP NMR 9 _Spectrometer, Diffusion,- Ions; Solid Electrolytes., 19 ABSTRACT (Continue on reverse if necessary and identify by block number) A pulsed field gradient nuclear magnetic resonance spectrometer was successfully constructed which is based on a superconducting magnet and has magic~angle spinning capabilities. A dewar facility ivan integral part of this system so as to permit investigation of ionic diffusigg down to 77 K, along with a sample heating arrangement for diffusion measurements up to 300'C. * This spectrometer has been employed in the measurements of protonic diffusion coefficients in 3" -alumina solid electrolytes and cation, anion and self-diffusion coefficients in aorious polymeric electrolytes..,/7/ 20 :)i5tr BuTON, AVAiL.ABIL,TY OF ABSTRACT 21 A8STRACT SEC, RiTY CLASSF.CATiON IEUNCLASS.FED/UNLiMITEO) G SAME AS Q7PT C3 Dr'C USEaS Unclassified 22a NIAME OF 4ESPON5i8LE NDiViDuAL 22 ',PMNE~it do Area Code)j 22c OFFCE 5 YM30L Dr. John Wilkes e2-96nc DO FORM S4 VAR 83 APR eaot.on fray Ood e,rit, ei~4.asteo SEC.Ry C.ASSiF CA- ON OF "~S '.j,_-

4 AIR FORCE OFFICE OF SCIENTIFIC RESEARCH AFOSR-TI Final Technical Report on Grant No. AFOSR A Pulsed Field Gradient Nuclear Magnetic Resonance Spectrometer for Direct Measurement of Ionic Diffusion in Solid Electrolytes ~DTIC TAB Principal Investigator JUstawowoad 0 Justitiaton Donald H. Whitmcre Northwestern University Availability Codes Avail sod/or Evanston. Illinois Dist SpeciaL April 1987

5 Final Technical Report on Grant No. AFOSR-eS-0098 We have successfully designed and constructed a working NNR pulsed field gradient (PFG) spin-echo spectrometer system for the direct observation of ion diffusivities in solid and amorphous electrolytes. A dedicated part of this system is a large-bore superconducting magnet installed in a low-loss helium dewar which was available for this purpose in Northwestern's Materials Research Center NMR Facility Laboratory. The moderate field of 4C' KOe provided by this magnet represents a compromise between the needed working volume (a 4-inch diameter room-temperature bore) to accommodate pulse field gradient NMR apparatus and the requisite field strength to improve sensitivity. An inert gas flow cryostat furnace, designed for highresolution NNR magnets by Oxford Instruments, is an integral part of our system; this unit includes controllers and transfer lines and permi:s measurements to be made over the temperature range from 77 to 600K. The pulsed spectrometer electronics used in this new system were patterned after an earlier circuit design originated at Northwestern University rgibson et al.. Rev. Sci. lnstr i14i), b,;: was conplemented by a high-power, wide-band transmitter and a dedicated microcomputer for signal averaging. The pulsed field gradient electronics and the pulsing unit, constructed in our e~ectronics shop following the origina; circuit design of Karlicek and Lowe [J Nag. Resonance (1980,1. a*lows gradient fields of 10 Oe/cm which is suitable for our new system An important advance in techniques for the direct observation of I~ffusion coefficients in solids and liquids results from a combination of coherent averaging VM methods and the pulsed field gradient approach : principle, the most powerful of these averaging methods :s that of mag:cangle spinning (MAS). a capability which we have incorporated into our PFS

6 spectrometer system. our MAS probe is a custom-made unit with var~able, temperature capability which allows multifrequency solid-state NMR and permits relaxation measurements to be accomplished on less sensitive nucle! such as nitrogen in the fast proton conducting electrolyte ammonium hydronium S"-alumina. Using our new PEG spectrometer, we have to-date made diffusion c,^efficien: measurements onl: ;a) some amorphous polymer electrolytes (r-,,a in polyethylene oxide/licf 3 so 3 complexes). (b) protonic ammonium/hydronium S "alumina and hydrogen uranyl glasses (H 5 n- 2 U0 2 (10 6 ) n mh 2 0).

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