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Synergistically enhanced thermal conductivity sensor based on AlN@h-BN/MWCNT nanocomposite for SF6 leakage monitoring in GIS.

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Title: Synergistically enhanced thermal conductivity sensor based on AlN@h-BN/MWCNT nanocomposite for SF6 leakage monitoring in GIS.
Authors: Wang, Faxun1,2 (AUTHOR), Lin, Junyi1,2 (AUTHOR) linjy9@csg.cn, Huang, Yuxuan1 (AUTHOR), Zhao, Jiguang2 (AUTHOR), Tian, Bing2 (AUTHOR), Zhao, Liang2 (AUTHOR), Luo, Bofeng2 (AUTHOR), Ye, Zhenliang2 (AUTHOR), Yang, Hao2 (AUTHOR), Duan, Guotao1 (AUTHOR) duangt@hust.edu.cn
Source: Sensors & Actuators B: Chemical. Jul2026, Vol. 458, pN.PAG-N.PAG. 1p.
Subjects: Nanocomposite materials, Gas leakage, Thermal conductivity measurement, Wheatstone bridge, Gas detectors
Abstract: Reliable, drift-resistant monitoring of SF 6 enrichment in air near gas-insulated switchgear (GIS) leak points remains challenging for compact and low-cost sensing nodes. Here we report a thermal-conductivity-differential sensor enabled by a materials-circuit co-design: a hierarchical AlN@h-BN/MWCNT nanocomposite coating is integrated onto a Pt-coil element and read out by a Wheatstone bridge with a sealed reference arm and differential amplification. The ternary architecture exhibits a well-developed mesoporous framework with a high BET surface area (111.03 m2·g−1), promoting efficient gas transport within the sensing layer and strengthening the thermal-conductivity-induced perturbation of the bridge balance. Under synthetic dry air (21% O 2 /79% N 2) at 25 ± 1℃, the output is monotonic over 0.1–5.0% SF 6 , with a recommended linear regime of 0.1–1.0% for quantitative readout; the baseline noise (σ air = 0.16 mV) yields an estimated LOD (3σ) of 0.0654% (∼654 ppm), while 0.1% is the lowest experimentally validated concentration. The optimized excitation voltage (3.0 V) maximizes response by balancing gas-phase modulation against increased non-gaseous heat losses at higher temperatures. The sensor shows reversible cycling (52/23 s response/recovery), humidity-tolerant operation (± 8% deviation over 20–80% RH), and < 5% degradation over 90 days; as expected for a TCD-type mechanism, cross-responses are governed by thermal conductivity rather than chemical selectivity. [Display omitted] • AlN@h-BN/MWCNT boosts heat spreading for SF 6 TCD in air. • Dual-element bridge co-design amplifies ΔU and improves stability. • SF 6 response is linear from 0.1% to 1.0% and monotonic to 5.0%. • Baseline noise σ air = 0.16 mV gives 3σ LOD of 654 ppm for SF 6. • Fast 52/23 s kinetics and < 5% drift over 90 d enable GIS alarming. [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
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Abstract:Reliable, drift-resistant monitoring of SF 6 enrichment in air near gas-insulated switchgear (GIS) leak points remains challenging for compact and low-cost sensing nodes. Here we report a thermal-conductivity-differential sensor enabled by a materials-circuit co-design: a hierarchical AlN@h-BN/MWCNT nanocomposite coating is integrated onto a Pt-coil element and read out by a Wheatstone bridge with a sealed reference arm and differential amplification. The ternary architecture exhibits a well-developed mesoporous framework with a high BET surface area (111.03 m2·g−1), promoting efficient gas transport within the sensing layer and strengthening the thermal-conductivity-induced perturbation of the bridge balance. Under synthetic dry air (21% O 2 /79% N 2) at 25 ± 1℃, the output is monotonic over 0.1–5.0% SF 6 , with a recommended linear regime of 0.1–1.0% for quantitative readout; the baseline noise (σ air = 0.16 mV) yields an estimated LOD (3σ) of 0.0654% (∼654 ppm), while 0.1% is the lowest experimentally validated concentration. The optimized excitation voltage (3.0 V) maximizes response by balancing gas-phase modulation against increased non-gaseous heat losses at higher temperatures. The sensor shows reversible cycling (52/23 s response/recovery), humidity-tolerant operation (± 8% deviation over 20–80% RH), and < 5% degradation over 90 days; as expected for a TCD-type mechanism, cross-responses are governed by thermal conductivity rather than chemical selectivity. [Display omitted] • AlN@h-BN/MWCNT boosts heat spreading for SF 6 TCD in air. • Dual-element bridge co-design amplifies ΔU and improves stability. • SF 6 response is linear from 0.1% to 1.0% and monotonic to 5.0%. • Baseline noise σ air = 0.16 mV gives 3σ LOD of 654 ppm for SF 6. • Fast 52/23 s kinetics and < 5% drift over 90 d enable GIS alarming. [ABSTRACT FROM AUTHOR]
ISSN:09254005
DOI:10.1016/j.snb.2026.139760