Thermal Treatment of Aerosol Deposited NiMn2O4 NTC Thermistors for Improved Aging Stability

Abstract

This paper examines the influence of a short-term thermal treatment of aerosol deposited negative temperature coefficient (NTC) thermistor films on the NTCR characteristics and their long-term stability with different electrode materials. An aerosol deposition of a spinel-based NiMn2O4 powder on alumina substrates with screen-printed AgPd and Au interdigital electrode structures was performed. The manufactured components of the typical size of 1206 were tempered in a moderate temperature range of 200 °C to 800 °C and aged for 1000 h at 125 °C in air. Based on R-T measurements in a high-precision silicone oil thermostat bath and high temperature XRD analyses, the influence of the thermal treatment was analyzed and discussed. A 60-min tempering at 400 °C proved to be optimal, as both the NTCR parameters and their ageing stability could be significantly improved. The findings are explained.

Powder aerosol deposition method — novel applications in the field of sensing and energy technology

“…62 Schubert et al carried out further investigations on the PAD of spinel-based NiMn 2 O 4 ceramics. 30,63,64 Besides the development of chip-based components (see Fig. 4), 63,64 these authors were focusing on tempering 30,63 and aging 63 of NTCR films.…”

“…30,63,64 Besides the development of chip-based components (see Fig. 4), 63,64 these authors were focusing on tempering 30,63 and aging 63 of NTCR films. They attributed the known tempering effect to a reduction of microstrain and crystallite growth and showed a significant improvement in aging stability.…”

“…Films tempered at 400 ○ C exhibit higher aging stability than conventionally sintered NiMn 2 O 4 bulk ceramics. 63 In the second approach, a thermally untreated powder mixture of the starting oxides is deposited and the deposited films are then thermally treated (in situ calcination 38 ). It was shown that mechanically stable films with cubic spinel structure and typical NTCR characteristics can be produced by powder aerosol co-deposition of a NiO-Mn 2 O 3 powder mixture followed by an in situ calcination of the composite films.…”

Modeling, Characterization and linearization of Negative Temperature Coefficient (NTC) Thermistor and Pressure Sensors

“…The coating material such as Aerosol Deposited NiMn2O4 plays an important role, while forming the leads of the sensor. The influence of this coating agent has the direct impact on the temperature detection and ageing [4]. The linearization method for these sensors is the major criteria due to their inherent characteristics of nonlinearity.…”

Novel Method for NTC Thermistor Production by Aerosol Co-Deposition and Combined Sintering

“…Despite the excellent thermistor properties, the process as it is described in References [18,19,24] has the disadvantage of the many process steps. As described above, a complete spinel formation is necessary, which requires a multi-stage powder preparation.…”