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1 – 2 of 2Tomasz Matusiak, Arkadiusz Dabrowski and Leszek Golonka
The purpose of this paper is to present the properties of thick-film resistors made of novel pastes prepared from glass and graphite.
Abstract
Purpose
The purpose of this paper is to present the properties of thick-film resistors made of novel pastes prepared from glass and graphite.
Design/methodology/approach
Graphite-based resistors were made of thick-film pastes with different graphite-to-glass mass fraction were prepared and examined. Sheet resistance, temperature coefficient of resistance, impact of humidity and short-term overload were investigated. The properties of the layers fired in atmospheres of air at 550°C and nitrogen at 875°C were compared.
Findings
Graphite-based resistors with various graphite-to-glass ratios made possible to obtain a wide range of sheet resistance from single O/square to few kO/square. These values were dependent on firing atmosphere, paste composition and the number of screen-printed layers. The samples made of paste with 1:1 graphite-to-glass ratio exhibited the temperature coefficient of resistance of about −1,000 ppm/°C, almost independently on the firing atmosphere and presence of a top coating. The resistors fired in the air after coating with overglaze, exhibited significantly lower sheet resistance, reduced impact of humidity and improved power capabilities.
Originality/value
In this paper, graphite-based resistors for applications in typical high-temperature cermet thick-film circuits were presented, whereas typical graphite-based resistors were fabricated in polymer thick-film technology. Owing to very low cost of the graphite, the material is suitable for low-power passive circuits, where components are not subjected into high temperature, above the typical temperature of operation of standard electronic components.
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Tomasz Matusiak, Krzysztof Swiderski, Jan Macioszczyk, Piotr Jamroz, Pawel Pohl and Leszek Golonka
The purpose of this paper is to present a study on miniaturized instruments for analytical chemistry with a microplasma as the excitation source.
Abstract
Purpose
The purpose of this paper is to present a study on miniaturized instruments for analytical chemistry with a microplasma as the excitation source.
Design/methodology/approach
The atmospheric pressure glow microdischarge could be ignited inside a ceramic structure between a solid anode and a liquid cathode. As a result of the cathode sputtering of the solution, it was possible to determine its chemical composition by analyzing the emission spectra of the discharge. Cathodes with microfluidic channels and two types of anodes were constructed. Both types were tested through experimentation. Impact of the electrodes geometry on the discharge was established. A cathode aperture of various sizes and anodes made from different materials were used.
Findings
The spectroscopic properties of the discharge and its usefulness in the analysis depended on the ceramic structure. The surface area of the cathode aperture and the flow rate of the solution influence on the detection limits (DLs) of Zn and Cd.
Originality/value
Constructed ceramic structures were able to excite elements and their laboratory-size systems. During the experiments, Zn and Cd were detected with DLs 0.024 and 0.053 mg/L, respectively.
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