: pp. 30-40
Lviv Polytechnic National University
Lviv Polytechnic National University, Ukraine
Lviv Polytechnic National University
Lviv Polytechnic National University
Technical University of Ilmenau, Germany

Progress  in  the  field  of  thermoelectricity  requires  the  further  development  of material  science  deep  into  the substance  through  the  use  of  the  achievements  of  applied  and  theoretical  advances  in  nanotechnologies,  including nanothermodynamics. This enables to expand the range of current thermodynamic forces, taking into account the forces inherent in nanostructured  substances,  and  to  increase  the  efficiency  of  attracting  the  concept  of  eddy  thermoelectric  currents  in  order  to increase the accuracy of temperature measurement by thermoelectric sensors. The researches of materials of thermoelectric sensors have  not  only  included  not  only  the  study  of  the  stability  of  thermoelectric  sensors,  but  their  study  by  their methods  of  non-destructive acoustic control. This makes it possible to assess and develop the role of specific mechanisms for the formation of eddy thermoelectric currents in the drift of thermoelectric power.

According  to  the results of acoustic studies of  thermometric materials of  thermoelectric sensors, the possibilities of  their characterization were  revealed  in  a non-destructive way. The  influence of micro  and nanostructural effects on  the  formation of local eddy thermoelectric currents as the source of thermoelectric power is evaluated. Taking into account thermodynamic forces and  flows  inherent  in  nanostructured  thermoelectric  materials,  it  becomes  possible  to  modify  the  concept  of  local  eddy thermoelectric  currents  concerning  the  enhancement  of  the  accuracy  of  temperature measurement. The mechanism  of  currents formation due  to  the  effect  of  coherence  in nanostructured materials  is  studied. Here minimal  temperature  changes  lead  to  the appearance of currents. On the other hand, the similar mechanism caused by the gradient of mechanical stresses raises. The latter permits  the modification  of  thermoelectric materials  by  forming multidimensional  fields  of  elastic micro  stresses  that  can  be especially effective for nanostructured thermoelectric materials.

Eddy  thermoelectric  currents,  for which  a  temperature gradient  is  required,  can be  considered  a partial  case of  a much broader class of eddy electrical currents occurring  in an electrically conducting substance under  the  influence of  fluctuations  in thermodynamic  parameters. The  stability  of  thermoelectric  power,  as well  as  its magnitude,  can  be  substantially  enhanced  in nanostructured  materials  by  the  direct  formation  of  gradients  of  thermodynamic  parameters,  different  from  the  temperature gradient.

[1]  Ju Li, Z.  Shan, E. Ma,  “Elastic  strain  engineering for  unprecendented materials  properties”, MRS Bull.,  vol.  39, pp. 108–114, Feb.2014,

[2]  M. Hÿtch,  A.  Minor,  “Observing  and  measuring strain in nanostructures and devices with transmission electron microscopy”,  MRS  Bull.,  vol.  39,  pp.  138–146,  Feb.2014,

[3]  D.  Yu,  Ji  Feng,  J.  Hone,  “Elastically  strained nanowires  and  atomic  sheets”, MRS  Bull.,  vol.  39,  pp.  157–166, Feb.2014,

[4]  V.  Kurylyuk,  A.  Korotchenkov,  Z.  Tsibriy,  A. Nikolenko,  V.  Strelchuk,  “Features  of  the  stressed  state  of germanium nanocrystals in the SiOx matrix”, Journ. of Nano- and Electronic Physics, vol. 7, no. 1, 01029 (5pp), 2015.

[5]  O.  Luste,  Physics  of  vortex  thermocouples  and measuring instruments on their basis, Autoref. dis., Chernivtsi, Ukraine: Institute of Thermoelectricity, 2003.

[6] O. Huk, B. Stadnyk, S. Yatsyshyn, “Long life cable thermoelectric  temperature  converters.  Reliability  problems”, Journ. of Thermoelectricity, no. 2, pp. 70–75, 2004.

[7]  L.  Anatychuk,  O.  Luste,  R.  Kuz,  M.  Strutinsky, “Inverse problems of  thermoelectricity”, Journal of Electronic Mat., vol. 80, is. 5, pp. 856–861, May 2011.

[8]  I. Rogelberg, V. Beylin, Alloys  for  thermocouples, Moscow, USSR: Metallurgy, 1983.

[9]  S.  R.  De  Groot,  Thermodynamics  of  Irreversible Processes,1952.  

[10]  N.  Bulatov,  A.  Lundin.  Thermodynamics  of irreversible physical and chemical processes, Moscow, USSR: Chemistry, 1984.

[11] R. Hanneman, H. Strong, “Pressure dependence of EMF  of  the  thermocouples  to  1300 oC  and  50  kBar”,  Journ. Appl. Phys., vol. 6, pp. 1052–1056, 1973.

[12]  S.  Hunt,  “AD8495  Interface  to  type  T thermocouples”,  Analog  Device.

[13]  H.  Hofmann,  Advanced  nanomaterials,  Course support, Powder Technology Laboratory,  IMX, EPFL, Version 1, Sept. 2009.

[14]  Z.  Chen,  G.  Han,  L.  Yang,  L.  Cheng,  J.  Zou, “Nanostructured thermoelectric materials: Current research and future challenge”, Progress in Natural Science: Mat. Internat., vol. 22, iss. 6, pp. 535–549, Dec. 2012.

[15] J. Paulini, G. Simon,  I. Decker, “Beam deflection in  electron  beam  welding  by  thermoelectric  eddy  currents”, Journ. of Phys. D: Appl. Phys., vol. 23, no. 5, pp. 486, 1990.

[16]  Pr.  Jood  et  al.  “Al-Doped  Zinc  Oxide Nanocomposites  with  Enhanced  Thermoelectric  Properties”, Nano Lett., vol. 11 (10), pp. 4337–4342, 2011.

[17] H. Carreon, B. Lakshminarayan, W. I. Faidi, A. H. Nayfeh, P. B. Nagy, On the role of material property gradients in noncontacting thermoelectric NDE, NDT & E International, vol. 36, pp. 339–348, 2003.

[18]  L.  Anatychuk,  “On  physical  models  of thermoelements”, Thermoelectricity, no. 1, pp. 5–17, 2003.

[19]  E.  Savary,   F.  Gascoin,   S.  Marinela,  “Fast synthesis  of  nanocrystalline Mg2Si  by  microwave  heating:  a new route to nano-structured thermoelectric materials”, Dalton Transactions, iss. 45, 2010.

[20] H. Carreon, P. Nagy, M. Blodgett, “Thermoelectric nondestructive  evaluation  of  residual  stress  in  shot-peened metals”, Journ. Res. in Nondestructive Evaluation, vol. 14, iss. 2, pp. 59–80, 2002, orig.article 2009.