Low-temperature sintered NTC ceramics for thick film temperature sensors

2012 ◽  
Vol 2012 (CICMT) ◽  
pp. 000536-000541
Author(s):  
T. Reimann ◽  
J. Töpfer ◽  
S. Barth
Keyword(s):  
Low Temperature ◽  
Thick Film ◽  
Chemical Interaction ◽  
Temperature Sensors ◽  
Liquid Phase Sintering ◽  
Sheet Resistivity ◽  
Microstructure Formation ◽  
Cu Substitution ◽  
Ntc Thermistor ◽  
Thermistor Material

Printed thick film NTC thermistors and multilayer devices are frequently used for temperature control in hybrid circuits. NiMn2O4 and substituted spinels are the most established materials for this application. For low-temperature sintering at 900 °C the shrinkage behavior of the thermistor material has to be adjusted by the addition of proper sinter additives. We investigated the chemical stability of NiMn2O4 and substituted spinels in air between 25 °C and 1200 °C. The compound NiMn2O4 is stable from 700 °C to 970 °C only and interacts with the sinter additives. Stable cubic spinels were found in the system ZnxNi0,5Co0,5Mn2-zO4. Addition of liquid phase sintering additives to the spinel powders results in complete densification at 900 °C. No chemical interaction between spinel and additive was observed. The effect of Cu-substitution into the spinel was also investigated. Functional NTC pastes were printed on alumina substrates and post-fired at 900 °C. The NTC thermistor films have a sheet resistivity of about 300 kOhm/sq and B = 3300 K. The firing behavior, microstructure formation and electric properties of NTC thick films will be reported.

Low-Temperature Sintered NTC Thermistor Ceramics for Thick-Film Temperature Sensors

2013 ◽  
Vol 10 (3) ◽  
pp. 428-434 ◽  
Author(s):  
Timmy Reimann ◽  
Jörg Töpfer ◽  
Stefan Barth ◽  
Heike Bartsch ◽  
Jens Müller
Keyword(s):  
Low Temperature ◽  
Thick Film ◽  
Temperature Sensors ◽  
Ntc Thermistor

Single superconducting quantum interference device multiplexer for arrays of low-temperature sensors

2001 ◽  
Vol 78 (3) ◽  
pp. 371-373 ◽  
Author(s):  
Jongsoo Yoon ◽  
John Clarke ◽  
J. M. Gildemeister ◽  
Adrian T. Lee ◽  
M. J. Myers ◽  
...  
Keyword(s):  
Low Temperature ◽  
Quantum Interference ◽  
Temperature Sensors ◽  
Superconducting Quantum Interference Device ◽  
Superconducting Quantum Interference

Thick Film Platinum Temperature Sensors

1986 ◽  
Vol 3 (1) ◽  
pp. 33-35 ◽  
Author(s):  
Q.M. Reynolds ◽  
M.G. Norton
Keyword(s):  
Thick Film ◽  
Temperature Sensors

Low temperature sintering of nano-SiC using a novel Al8B4C7 additive

2010 ◽  
Vol 25 (3) ◽  
pp. 471-475 ◽  
Author(s):  
Sea-Hoon Lee ◽  
Byung-Nam Kim ◽  
Hidehiko Tanaka
Keyword(s):  
Grain Size ◽  
Liquid Phase ◽  
Low Temperature ◽  
Sintering Temperature ◽  
Applied Pressure ◽  
Liquid Phase Sintering ◽  
Low Temperature Sintering ◽  
Densification Rate ◽  
Sintering Additive ◽  
Average Grain Size

Al8B4C7 was used as a sintering additive for the densification of nano-SiC powder. The average grain size was approximately 70 nm after sintering SiC-12.5wt% Al8B4C7 at 1550 °C. The densification rate strongly depended on the sintering temperature and the applied pressure. The rearrangement of SiC particles occurred at the initial shrinkage, while viscous flow and liquid phase sintering became important at the middle and final stage of densification.

Pressure-Assisted Sintering of Buried Thick Film Resistors in LTCC

2015 ◽  
Vol 2015 (CICMT) ◽  
pp. 000239-000244
Author(s):  
Andreas Heunisch ◽  
Victor de Seauve ◽  
Torsten Rabe
Keyword(s):  
Thick Film ◽  
Electrical Resistance ◽  
Particle Distribution ◽  
Laser Diffraction ◽  
The Other ◽  
Sintering Process ◽  
Sheet Resistivity ◽  
Green Tape ◽  
Small Fluctuation ◽  
Conductive Phase

In this work, the effect of the pressure-assisted sintering process on buried thick film resistors integrated in LTCC multilayer has been studied. Four commercial resistor pastes with sheet resistivities between 10 kΩ and 10 MΩ/cm were analyzed. First they were characterized by SEM/EDX, XRD and Laser diffraction to determine composition and particle distribution. The pastes consist of isolating particles and of Ruthenium based particles that are supposed to build the conductive phase. The pastes were screen printed on LTCC green tape (DP 951) and buried in four layer laminates. Sintering was done in two ways, pressureless (PLS) and also pressure-assisted (PAS). The pressureless sintered resistors showed electrical resistance values roughly in the range of the nominal sheet resistivity and only relatively small fluctuation within one sample. The PAS samples on the other hand showed significantly higher resistances and larger deviations. The microstructure of the sintered resistors was again investigated by SEM and XRD. It seems that the resistivity is determined by the ratio of the two Ruthenium phases RuO2 and Pb2Ru2O6.5, where RuO2 has the higher conductivity. Buried resistors cannot be trimmed by a laser to adjust the resistance. But we discovered that a refiring step will reduce and normalize the resistivity of the PAS resistors significantly.

Evaluation of screen-printable type S (Pt-PtRh) thermocouples on different ceramic substrates

2016 ◽  
Vol 2016 (CICMT) ◽  
pp. 000053-000057
Author(s):  
Jaroslaw Kita ◽  
Sven Wiegärtner ◽  
Alistair Prince ◽  
Peter Weigand ◽  
Ralf Moos
Keyword(s):  
High Temperature ◽  
Thick Film ◽  
Screen Printing ◽  
Temperature Sensors ◽  
Electrical Characteristics ◽  
Buried Structures ◽  
Ceramic Substrates ◽  
Temperature Characteristics ◽  
Film Type ◽  
Thick Film Technology

Abstract The application of thermocouples as temperature sensors has been well known and has already been established for many years. However, for classical thick-film technology using screen-printing and firing, no standardized solutions exist. The here-presented newly developed PtRh thick-film compositions (90% Pt,10% Rh) allows to construct thick-film type S thermocouples (Pt/PtRh), following the IEC temperature characteristics. They can be fired in air, and therefore can be easily integrated into existing thick-film components and devices. In an earlier study, the new Pt-Rh composition was successfully tested on alumina substrates. Their electrical characteristics is equal with classical wire type S thermocouples. This study continues the investigations of thick-film thermocouples. We tested the newly developed pastes for high temperature applications on alumina substrates and evaluated the application of the new screen-printable type S thermocouples on LTCC ceramics. Three possible configurations were investigated: deposited on already fired LTCC substrates (post-fired), screen-printed and co-fired with LTCC tapes on the top surface as well as as buried structures. The paper presents the results of our evaluation and discusses further possible applications.

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