Earticle

초록

영어

Vanadium trioxide (V2O3) has emerged as a promising candidate for smart electrical insulation for use in rare-earth barium copper oxide (REBCO) magnets due to its metal-to-insulator transition (MIT) behavior. V2O3 maintains high resistivity at the operating temperature of 77 K to ensure an insulated state. However, it automatically drops to low a resistivity value as the temperature approaches approximately 150 K. Such a dramatic transition allows the turn-to-turn contact resistance (Rct) in REBCO coils to shift from the insulating to the metallic state, facilitating the effective bypass and redistribution of current during quench events. Thus, V2O3 can function as a thermally activated switching layer that combines the rapid electromagnetic response of insulated coils with the enhanced self-protection capability of non-insulated coils. This study experimentally investigates the repeatability and reproducibility of the MIT characteristics of a V2O3 insulation layer fabricated using a paste-coating process and sandwiched between REBCO tapes. The thermal-cycle repeatability was evaluated using two independently prepared samples, each subjected to ten continuous thermal cycles under the same measurement conditions. For the first sample, the mean transition temperature (Trt) was137.32 K, with a standard deviation (σTrt) of 1.56 K. The second sample also exhibited a consistent MIT behavior, with a mean Trt of 142.58 K and a σTrt of 1.42 K. These results confirm that the MIT behavior of V2O3 insulation is repeatable with small standard deviation under repeated thermal cycling tests. In addition, the pressure dependence of Rct was examined under applied torque values ranging from 0.1 to 6.0 N·m. The results show that Rct is highly sensitive to contact pressure. In particular, at 77 K, a substantial decrease in Rct was observed when the applied torque reached 5 N·m or higher. Finally, the reproducibility of the V₂O₃ insulation material was investigated using ten independently fabricated samples. These samples exhibited a mean insulation thickness of 96.6 μm with a standard deviation of 13.26 μm, while their MIT behavior remained reproducible within the tested sample set, with a mean Trt of 147.09 K. These findings provide short-sample interface-level data for future V₂O₃-based smart-insulation design. However, wound-coil experiments are still required to verify coil-level self-protection performance.

목차

Abstract
1. INTRODUCTION
2. EXPERIMENT SETUP
3. RESULTS
3.1. R–T characteristics of V2O3 under contact pressure
3.2. Thermal cycle repeatability of V2O3 insulation layer
3.3. Reproducibility of ten independently fabricated samples
4. CONCLUSION
ACKNOWLEDGMENT
REFERENCES

키워드

저자

• Huu Luong Quach [ Faculty of Electrical Engineering, Can Tho University, Can Tho, Viet Nam ]
• Hoon Jung [ Electric Energy Research Center, Jeju National University, Jeju, Korea ]
• Ho Min Kim [ Electric Energy Research Center, Jeju National University, Jeju, Korea ]
• Ji Hyung Kim [ Department of Electrical & Energy Engineering, Jeju National University, Jeju, Korea ] Corresponding Author
• Sung Hoon Lee [ Department of Electrical & Energy Engineering, Jeju National University, Jeju, Korea ] Corresponding Author

참고문헌

발행기관

간행물

표지보기 관심저널 등록

• 간행물명

  한국초전도·저온논문지 (구 한국초전도저온공학회논문지) [Progress in Superconductivity and Cryogenics]

• 간기

  계간

• pISSN

  1229-3008

• eISSN

  2287-6251

• 수록기간

  1999~2026

• 등재여부

  KCI 등재,SCOPUS

• 십진분류

  KDC 427 DDC 537