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The aim of this paper is to investigate the behavior of a new nanometric particle NTC thermistor paste and thick films obtained by screen printing.

Nanometric powder of NTC thermistors based on complex spinel was made by calcination of an oxide mixture and ultra fast ball milling. Characterization of the new powder was done on compacts sintered in different conditions. Segmented thermistors were screen printed on alumina substrata, dried and fired in a conveyor furnace at 850°C/10 min. Segmented thermistors were indirectly heated by a glass sealed heater placed between them in the middle. The system was put in a tube with a regulated air flow to serve as a volume thermistor sensor based on heat loss.

The sintered thick film samples and NTC powder compacts measurements could help in choosing the optimal technology conditions during the production of NTC devices. The NTC segmented thermistors were suitable both for heated sensors and self heated sensors.

Low temperature thick film thermistor pastes based on nanometer powder of complex spinel are of interest due to their importance in sensor applications.

This work predicts that high temperature pastes of the same material can be realized with characteristics superior to those of low temperature paste such as NTC 3K3 or similar.

As leading sensors of ambient conditions, temperature sensors act as important sensing devices. They are essential in a large variety of products. A variety of temperature sensors is available on the market to meet specific application needs. The most common include thermocouples, resistive temperature detectors (RTD), thermistors, and silicon‐based sensors. But of all of these temperature sensors, the thermistor is the only one that holds the esteemed position owing to its high sensitivity, accuracy and low cost. Temperature measurement systems utilizing thermistors are less expensive to produce because few additional components are required, especially in the present era of embedded systems. With the recent advances in manufacturing techniques, the drawbacks of conventional thermistors, like aging, interchangeability, unreliability etc., are almost eliminated. Booming demand for DVD players and portable communication appliances have pushed up the popularity of NTC thermistors. This article reviews the latest trends in thermistor manufacturing and the associated applications.

Thick film thermistors based on the thermistor powder of the sintered ceramic thermistor, prepared from oxides of nickel, cobalt and manganese, were fabricated and studied. The ingredient compositions, including the composition proportions, influenced the properties of thick film thermistors. The effects of the compositions of the sintered ceramic thermistors, the amounts of additives used and the compositions of the glass binders on the properties of the thick film thermistors were also studied.

The paper aims to focus on thick film planar thermistors.

Thick film planar thermistors such as rectangular, sandwich, multilayer, segmented and interdigitated were printed of law temperature NTC paste called NTC 3K3 95/2 (Ei Iritel). Their resistivity was measured at room temperature as a function of volume resistivity variations due to electrode effect (diffusion of PdAg into NTC layer) and variation of geometrical parameters such as length l, width w, thickness d, number of segments n. The experimental data obtained were used in forming a model by the simple fitting procedure for counting diffusion effect on volume resistivity and resistivity dependence on geometrical parameters.

Thermal behavior of NTC thick films was measured in the range of −30‐120°C. Exponential factor B was fitted for measured values and included in the proposed thick film thermistors model. The agreement of measured and calculated data enables simulation of new thermistor geometries.

The paper focuses on the experiment which was the first step in forming a total physical/mathematical model proposed for thick film thermistor resistivity.

This paper presents experimental data associated with the properties of thick film thermistors based on a spinel‐type semiconducting oxide/RuO2/glass system. The following parameters—sheet resistivity, thermistor (B) and thermal time (?) constants—have been measured, all as functions of different composition and construction variants. The thermistor properties are independent of configuration and are mainly determined by the semiconducting oxide particle chains. The correlation between B and ? for the compositions considered has been observed.

The direct overlapping of thick film NTC thermistors and resistors was attempted to enable the trimming of NTC thermistors to relatively narrow tolerances with little influence on beta factors. Different combinations of 1 kohm/□ thick film NTC material (4993, Remex) and 1 and 10 kohm/□RuO2 and ruthenate based thick film resistors (HS‐80 series, Du Pont), fired either together or separately, were tested. The sheet resistivities, TCR and beta factors of these combinations were measured. Microstructures were investigated by SEM and analysed by EDS. The results, i.e., the large decrease of sheet resistivities (up to ten times) and a resistivity vs. temperature dependence which changed from negative to positive TCR for some combinations, indicate the interaction between NTC materials and resistors during the firing process. These interactions are more distinctive for materials fired together. In all cases the beta factors were lower than calculated. Based on these experiments, the ‘best’ thick film resistor paste for NTC/resistor combination (HS‐8041, Du Pont) was chosen. Several layouts with partially or entirely overlapped NTC thermistors/resistors were designed. Unprotected, glass protected or organic protected circuits were laser trimmed. The resistivities and beta factors were measured as a function of resistor geometries and laser cut lengths. The results obtained demonstrated that NTC thermistors, partially overprinted with an ‘ordinary’ thick film resistor, can be trimmed to tolerances around 0.5% without any special precautions during trimming.

The purpose of this work was to characterize NiMn₂O₄ spinel-based thermistor powder, to use it in screen printing technology to fabricate temperature sensors, to study their performance for different sintering temperatures of thermistor layer, with and without insulative cover, as well as to investigate stability of the fabricated thermistors and their applicability in water quality monitoring.

After the characterization of starting NiMn₂O₄ spinel-based thermistor powder, it was converted to thick film paste which was screen printed on alumina substrate. Thermistor layers were sintered at four different sintering temperatures: 980°C, 1050°C, 1150°C and 1290°C. An interdigitated pattern of Ag-Pd conductive layer was used to reduce the resistance. Temperature-resistance characteristics were investigated in air and water, with and without insulative cover atop the thermistor layer. Stability of the fabricated thermistors after aging at 120°C for 300 h was also examined.

Thick film NiMn₂O₄ spinel thermistors, prepared by screen printing and sintering in the temperature range 980°C–1290°C, exhibited good negative temperature coefficient (NTC) characteristics in the temperature range −30°C to 145°C, including high temperature coefficient of resistance, good stability and applicability in water.

This study explores the range of sintering temperature that can be applied for NiMn₂O₄ thermistor thick films without compromising on the temperature sensing performance in air and water, as well as stability of the thermistors after aging at elevated temperatures.

Aims to focus on temperature sensors.

Negative temperature co‐efficient thermistor powders of ternary Mn, Co, Ni oxide along with RuO₂ synthesized at relatively moderates temperature (1,000°C). Thick film thermistor paste compositions were formulated by mixing the semiconducting oxide powder, glass frit and organic vehicle. The physico‐chemical analysis, viz. X‐ray diffraction, scanning electron microscopy and thermogravimetry and IR spectroscopy were carried out for the synthesized powder and the resultant thick films. The X‐ray analysis of the powders showed the cubic spinel structure. The electrical properties like thermistor constant, sensitivity index and activation energy of the thick film NTC thermistor were determined.

The room temperature resistance is observed to range from 490 KΩ to 4.13 MΩ with thermistor constant ranging from 3,275 to 3,980 K, in the temperature range of 25‐300°C.

Describes research work on temperature sensors that are used for monitoring and control in many fields such as in home appliances, manufacturing industries, biomedical and automobile industries.

The purpose of this paper is to study the properties of disc type negative temperature coefficient (NTC) thermistors based on the spinel system Mn‐Co‐Ni‐O with the doping of RuO₂ for the low‐resistance applications.

Emphasis was placed on the properties of ruthenium dioxide doped manganite spinel system for low‐resistance applications. The properties such as microstructure, X‐ray diffraction analysis and electrical properties are reported.

The prepared NTC thermistor compositions revealed the room temperature resistance and thermistor constant in the range of 28‐2,950 Ω and 1,539‐3,428 K, respectively. Hence, the prepared NTC thermistors with low resistance and moderate sensitivity are suitable from an industrial applications point of view.

The paper reports upon a synthesis procedure which is a straightforward preparation of highly densified ternary oxide (Mn‐Co‐No‐O) thermistors.

The aim of the present work was the characterization of a group of compounds with the perovskite‐type structure in respect of their applicability as thermistor materials.

Four compositions: La_0.7Sr_0.3Zr_0.5Co_0.2²⁺Co_0.3³⁺O₃, La_0.8Sr_0.2Ti_0.5Co_0.3²⁺Co_0.2³⁺O₃, La_0.4Sr_0.6Ti_0.3Fe_0.7O₃ and CaTi_0.8Co_0.2O₃ were synthesized by solid‐state reaction. Ceramic thermistor materials were sintered in the temperature range 1,300‐1,400°C. The synthesized powders were used for fabrication of thick film pastes and thermistors fired at 1,100‐1,250°C. Resistance‐temperature characteristics of the ceramic samples were studied in the range −55 to 800°C for the ceramic samples and 20‐600°C for thick films. Endurance tests at 300°C for 500 h were performed.

The developed NTC materials exhibited high temperature coefficients of resistivity, dense microstructure and good stability. The most advantageous characteristics have been shown by La_0.7Sr_0.3Zr_0.5Co_0.2²⁺Co_0.3³⁺O₃ and La_0.8Sr_0.2Ti_0.5Co_0.3²⁺Co_0.2³⁺O₃ thermistors. The highest Temperature coefficient of resistances for the ceramics were found in the temperature range from −55 to 180°C (−10.7 to −2.9 per cent/°C) and for the thick films in the temperature range 40‐300°C (−5.6 to −1.5 per cent/°C).

This work has been focused on preliminary choice of compositions appropriate for practical thermistor thick film applications. Elucidation of conduction mechanism of the investigated materials needs further complex studies of conductivity, nonstoichiometry, thermoelectric power, etc. as a function of temperature and oxygen partial pressure.

In this work, an attempt has been made to extend the typical range of NTC compositions and to fulfil the demand for improved stability of bulk and thick film thermistors at elevated temperatures.