TY - JOUR
T1 - New High Temperature Dielectrics: Bi-free tungsten bronze ceramics with stable permittivity over a very wide temperature range
AU - Brown, Thomas
AU - Brown, Andy P.
AU - Hall, David A.
AU - Hooper, Thomas E.
AU - Li, Yizhe
AU - Micklethwaite, Stuart
AU - Aslam, Zabeada
AU - Milne, Steven J
PY - 2020/10
Y1 - 2020/10
N2 - High relative permittivity, εr, over a very wide temperature range, −65 ⁰C to 325 ⁰C, is presented for ceramics designed to be compatible with base metal electrode multilayer capacitor manufacturing processes. We report a ≥ 300 ⁰C potential Class II capacitor material, free from Bi or Pb ions, developed by doping Sr2NaNb5O15 with Ca2+, Y3+ and Zr4+ ions, according to the formulation Sr2−2zCazYzNaNb5-zZrzO15. For sample composition z = 0.025, εr values are 1565 ± 15 % (1 kHz) from −65 °C to 325 °C. At a slightly higher level of doping, z = 0.05, εr values are 1310 ± 10 % from −65 °C to 300 °C. Values of the dielectric loss tangent, tanδ are ≤ 0.025 from −60 °C to 290 °C, for z = 0.025, with tanδ increasing to 0.035 at 325 ⁰C. Microstructural analyses exclude core-shell mechanisms being responsible for the flattening of the εr –T response.
AB - High relative permittivity, εr, over a very wide temperature range, −65 ⁰C to 325 ⁰C, is presented for ceramics designed to be compatible with base metal electrode multilayer capacitor manufacturing processes. We report a ≥ 300 ⁰C potential Class II capacitor material, free from Bi or Pb ions, developed by doping Sr2NaNb5O15 with Ca2+, Y3+ and Zr4+ ions, according to the formulation Sr2−2zCazYzNaNb5-zZrzO15. For sample composition z = 0.025, εr values are 1565 ± 15 % (1 kHz) from −65 °C to 325 °C. At a slightly higher level of doping, z = 0.05, εr values are 1310 ± 10 % from −65 °C to 300 °C. Values of the dielectric loss tangent, tanδ are ≤ 0.025 from −60 °C to 290 °C, for z = 0.025, with tanδ increasing to 0.035 at 325 ⁰C. Microstructural analyses exclude core-shell mechanisms being responsible for the flattening of the εr –T response.
U2 - 10.1016/j.jeurceramsoc.2020.10.034
DO - 10.1016/j.jeurceramsoc.2020.10.034
M3 - Article
SN - 0955-2219
JO - Journal of the European Ceramic Society
JF - Journal of the European Ceramic Society
ER -