{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,10]],"date-time":"2026-05-10T03:40:05Z","timestamp":1778384405325,"version":"3.51.4"},"reference-count":17,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2017,11,27]],"date-time":"2017-11-27T00:00:00Z","timestamp":1511740800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Continuous ultrasonic in-situ monitoring for industrial applications is difficult owing to the high operating temperatures in industrial fields. It is expected that ultrasonic transducers consisting of a CaBi4Ti4O15(CBT)\/Pb(Zr,Ti)O3(PZT) sol-gel composite could be one solution for ultrasonic nondestructive testing (NDT) above 500 \u00b0C because no couplant is required and CBT has a high Curie temperature. To verify the high temperature durability, CBT\/PZT sol-gel composite films were fabricated on titanium substrates by spray coating, and the CBT\/PZT samples were tested in a furnace at various temperatures. Reflected echoes with a high signal-to-noise ratio were observed up to 600 \u00b0C. A thermal cycle test was conducted from room temperature to 600 \u00b0C, and no significant deterioration was found after the second thermal cycle. To investigate the long-term high-temperature durability, a CBT\/PZT ultrasonic transducer was tested in the furnace at 600 \u00b0C for 36 h. Ultrasonic responses were recorded every 3 h, and the sensitivity and signal-to-noise ratio were stable throughout the experiment.<\/jats:p>","DOI":"10.3390\/s17122740","type":"journal-article","created":{"date-parts":[[2017,11,27]],"date-time":"2017-11-27T11:07:08Z","timestamp":1511780828000},"page":"2740","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Mn-Doped CaBi4Ti4O15\/Pb(Zr,Ti)O3 Ultrasonic Transducers for Continuous Monitoring at Elevated Temperatures"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4711-530X","authenticated-orcid":false,"given":"Makiko","family":"Kobayashi","sequence":"first","affiliation":[{"name":"Faculty of Advanced Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Taiga","family":"Kibe","sequence":"additional","affiliation":[{"name":"Faculty of Advanced Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hajime","family":"Nagata","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Tokyo University of Science, Tokyo 162-0825, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2017,11,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Tipping, P.G. 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