(Ti,Sn) Solid Solution Based Gas Sensors for New Monitoring of Hydraulic Oil Degradation

Abstract

The proper operation of a fluid power system in terms of efficiency and reliability is directly related to the fluid state; therefore, the monitoring of fluid ageing in real time is fundamental to prevent machine failures. For this aim, an innovative methodology based on fluid vapor analysis through metal oxide (shortened: MOX) gas sensors has been developed. Two apparatuses were designed and realized: (i) a dedicated test bench to fast-age the fluid under controlled conditions; (ii) a laboratory MOX sensor system to test the headspace of the aged fluid samples. To prepare the set of MOX gas sensors suitable to detect the analytes’ concentrations in the fluid headspace, different functional materials were synthesized in the form of nanopowders, characterizing them by electron microscopy and X-ray diffraction. The powders were deposited through screen-printing technology, realizing thick-film gas sensors on which dynamical responses in the presence of the fluid headspace were obtained. It resulted that gas sensors based on solid solution TixSn1–xO2 with x = 0.9 and 0.5 offered the best responses toward the fluid headspace with lower response and recovery times. Furthermore, a decrease in the responses (for all sensors) with fluid ageing was observed.

On the Efficiency of Mobile Hydraulic Power Packs Operating with New and Aged Eco-Friendly Fluids

“…A specific experimental test bench was developed to perform the study described in [23], with the aim of aging the hydraulic fluids fast and continuously, under controlled conditions and excluding contamination by external agents. The aging was caused by stressing and heating the fluid, simply running the pump with the regulating relief valve.…”

Semiconductor Oxide Gas Sensors: Correlation between Conduction Mechanisms and Their Sensing Performances

“…A selection of semiconducting oxides (single or combined, such as SnO 2 MoO 3 , WO 3 , ZnO, TiO 2 , Ti-Sn, W-Sn, Mn-W mixed oxides, etc.) were prepared using wet chemistry methods [6,7]. The synthesis procedures were optimized to obtain nanopowders with a single phase, and a homogenous distribution in grain size (analyzed by X-ray diffraction and scanning electron microscopy, respectively) was presented.…”

Growth Mechanisms of ZnO Micro-Nanomorphologies and Their Role in Enhancing Gas Sensing Properties

“…However, the most relevant application of MOXs in chemical sensing is in realization of chemiresistors. Air quality monitoring in indoor/outdoor environment [21][22][23][24][25], clinical disease diagnosis [26], food quality monitoring [27], diagnostics for industrial systems [28], and safety control devices, [29] are important examples of such applications.…”