Search results

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 purpose of this paper is to ascertain chemical changes occurring at various stages involved in processing of silver‐based photoimageable thick films; and to determine ensuing topographical features which other wise appeared to be hindered in 2D scanning electron microscopy.

Surface sensitive techniques, viz. X‐ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were used.

Interfacial adhesion of silver film with substrate (Al₂O₃) was specifically looked into with respect to role played by photoimaging (before and after exposure to ultra‐violet light). XPS results revealed occurrence of subtle chemical changes in terms of unsaturation to saturation in C−C bonding and also an interesting C−Al bonding which presumably improves mechanical adhesion of unfired film with the alumina substrate. AFM was carried out to examine the surface roughness, particle size, and microstructure of film which are very important from the standpoint of high‐frequency applications.

Surface sensitive techniques like XPS and AFM were exclusively used in order to characterize silver‐based photoimageable thick films.

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.