Electrical Properties of Y0.06Sr0.94Ti0.6Fe0.4O3-δ-YSZ Composites as Electrode Materials

Y0.06Sr0.94Ti0.6Fe0.4O3-δ-YSZ composites were prepared by mixing Y, Fe co-doped SrTiO3 (Y0.06Sr0.94Ti0.6Fe0.4O3-δ known as YSTF) and 8 mol% Y2O3 stabilized ZrO2 (YSZ) in different weight fractions. The phase stability, phase compatibility, microstructure and mixed ionic-electronic conductivity of composites were investigated. Phase analysis by XRD showed no clearly detectable secondary phases. The electrical conductivity measurement on the YSTF-YSZ composites showed a drastic decrease in total electrical and ionic conductivities when more than 10 wt% of YSZ was used in the composites. The total electrical conductivity was 0.102 S/cm for Y0.06Sr0.94Ti0.6Fe0.4O3-δ and 0.043 S/cm for YSTF-20YSZ at 700 oC, respectively. The value at 700 oC is approximately 2.4 times higher than that of YSTF-20YSZ. The ionic conductivity of Y0.06Sr0.94Ti0.8Fe0.2O3-δ varies from 0.015S/cm at 700 oC to 0.02 S/cm at 800 oC, respectively. The value at 800°C is approximately 12.5 times higher than YSTF-20YSZ. The ion transference numbers of YSTF-YSZ composites vary from 0.14 to 0.28 at 800 °C.

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Control of Pedicle Screw Placement with an Electrical Conductivity Measurement Device: Initial Evaluation in the Thoracic and Lumbar Spine

Advances in Medicine ◽

10.1155/2016/4296294 ◽

2016 ◽

Vol 2016 ◽

pp. 1-7 ◽

Cited By ~ 3

Author(s):

Olaf Suess ◽

Markus Schomacher

Keyword(s):

Electrical Conductivity ◽

Electronic Conductivity ◽

Spinal Instrumentation ◽

Pedicle Screws ◽

Conductivity Measurement ◽

Electrical Conductivity Measurement ◽

Measurement Device ◽

Degenerative Spinal Disease ◽

Single Use ◽

Transpedicular Screw Fixation

Aim. Transpedicular screw fixation is widely used in spinal surgery. But the insertion of pedicle screws can sometimes be challenging because of the variability in pedicle size and the proximity of nerve roots.Methods. We detected intraoperatively the sensitivity for iatrogenic pedicel perforation with a hand-held electronic conductivity measurement device (ECD) that measures electrical conductivity of tissue-medium surrounding the instrument tip. ECD was used to guide the placement of 84 pedicle screws in 15 patients undergoing surgery for tumor or degenerative spinal disease at various spinal levels from T8 to L5. Additionally a CT-scan controlled screw positioning postoperatively.Results. The placement was “correct” (no mediocaudal pedicle wall penetration) for 78 of 84 (92,8%) screws, “suboptimal but acceptable” (0–2 mm penetration) for 4 of 84 (4,8%) screws, and “misplaced” (penetration > 2 mm) for 2 of 84 (2,4%) screws.Conclusion. Although this study was not designed to compare electronic conductivity technique to other guidance methods, such as fluoroscopy or navigation, a convincing “proof of concept” for ECD use in spinal instrumentation could be demonstrated. Advantages include easy handling without time-consuming setup and reduced X-ray exposure. However, further investigations are necessary to evaluate i.a. the economic aspects for this single-use developed instrument.

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