Electrochemical monitoring of water–surfactant interactions in industrial lubricants

Smiechowski, Matthew F.; Lvovich, Vadim F.

doi:10.1016/s0022-0728(02)01106-3

Cited by 53 publications

(43 citation statements)

References 10 publications

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“…AC impedance spectroscopy has been used to measure the conductivity of industrial polymers and colloids, which are classified as lowconductivity and high resistance media 7 . Its feasibility in detecting contamination of industrial lubricants by water 8 and glycol leakage 9 as well as diesel contamination by soot 10 , the influences of lubricant chemical compositions 7 , the effect of steel in jet engine oil 11 and changes in industrial cutting fluids 12 have also been investigated. As oil degrades, its electrical conductivity changes due to changes in the concentration of "conductive species" in the oil.…”

Section: Introductionmentioning

confidence: 99%

Base oil oxidation detection using novel chemical sensors and impedance spectroscopy measurements

Soleimani

Sophocleous

Wang

et al. 2014

Sensors and Actuators B: Chemical

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Lubricating oils are employed in machinery to minimise friction, remove heat and wear particles, protect against corrosion etc. Mineral base oils are derived from natural crude oil through a distillation process and are divided into five main groups depending on volume of sulphur, saturate and viscosity index, according to the American Petroleum Institute (API). As lubricating base oil oxidises, acidic by-products are formed and oil viscosity increases due to progressive polycondensation of higher molecular weight products. In this work, thick film (TF) potentiometric sensors based on ion-selective electrodes (ISE) have been developed for oil acidity measurement to enable online oil condition monitoring. A TF ruthenium oxide (RuO 2 ) working electrode and three types of TF reference electrodes were fabricated and tested in oxidised base oil samples prepared at the Shell Houston laboratories. The TF sensors were evaluated by comparison with acid number (AN) measurement and also compared with oil conductivity measurements using impedance spectroscopy. The results show that the conductivity, viscosity and AN of the oil samples increase with the level of oil oxidisation. The output of the TF sensors detected the acidity increase of the oxidised oil samples at both 50 and 80 °C and displayed a linear relationship with oil AN.

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Section: Introductionmentioning

confidence: 99%

Base oil oxidation detection using novel chemical sensors and impedance spectroscopy measurements

Soleimani

Sophocleous

Wang

et al. 2014

Sensors and Actuators B: Chemical

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“…Oil quality decreases due to oxidation and contamination, such as debris, fuel and coolant dilution etc 1 . At low levels water solubilises in oil and can react with lubricating additives to reduce their effectiveness, while at higher contents it forms an emulsion which can decrease viscosity 2 . Fuel and glycol contaminants can dilute oil leading to a reduction in viscosity.…”

Section: Introductionmentioning

confidence: 99%

Engine oil acidity detection using solid state ion selective electrodes

Soleimani

Sophocleous

Glanc

et al. 2013

Tribology International

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Lubricating oil of moving parts is a critical factor for the performance and longevity of cars and industrial engines. The lubricant degradation occurring during application can be detrimental to the proper operation of lubricated machines if the oil is not changed in a timely manner. However, the oil degradation process is often influenced by a number of parameters, such as the operating temperature and contamination. This offers a challenge to oil monitoring technologies. This study investigates the feasibility of detecting changes in oil acidity using Ion Selective Electrodes (ISE) fabricated using thick-film (TF) screen printing technology. The working electrode is a TF Ruthenium Oxide (RuO 2 ) ISE; the reference electrodes are three different types of TF reference electrodes and commercial glass pH reference electrode. Artificially degraded oil samples from oxidation tests and model oils produced by adding acid have been used for the evaluation of the sensors. Acid Number (AN) of all oil samples was obtained using conventional titration method. The results show that the TF electrodes responded linearly to the change in oil acidity under different temperatures. Their sensitivity in detecting oil acidity in the model oils is found to be much higher than that of the commercial electrode. Initial analysis also shows that the sensor responses decrease as the temperature increases.

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“…Our previous publications established an interpretation of physical and chemical characteristics of a typical lubricant using the linear (5-6) and non-linear higher harmonic EIS analysis (7) for investigating the effects of oil oxidation; contamination with water (8), soot (9) and fuel (10); and development of various monitoring devices for lubricants' performance diagnostics (11)(12). These studies were based on initial knowledge of chemical composition and physical properties of lubricants, and determining the response of various segments of the EIS spectrum to variations in the lubricants' degradation, chemical composition, electrochemical dc potential, temperature and electrode geometry.…”

Section: Introductionmentioning

confidence: 99%

“…The impedance is always measured between two reference electrodes, that is, the total measured impedance includes that of the counter electrode, the electrolyte solution and the working electrode. This type of electrode arrangement is typically used if it is impossible to position a reference electrode in the electrochemical cell, for example in the characterization of batteries, or when it is important to maintain a homogeneous current distribution, as in low conductivity media where an inhomogeneous current distribution can lead to measurement artifacts (5)(6)(7)(8)(9)(10)(11)(12). In highly resistive media this often results in the interfacial polarization effects being predominant in the low-frequency impedance region.…”

Section: Introductionmentioning

confidence: 99%

AC Impedance Characterization of Highly Resistive Media Using Four-Electrode Electrochemical Cells

Lvovich

Smiechowski

2010

ECS Trans.

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Electrochemical impedance spectroscopy (EIS) was employed for characterization studies of highly resistive non-aqueous media using four-electrode cells with solid state reference electrodes. The influence of internal resistance of the impedance analyzer, the media's temperature and conductivity, shielding of the cables, and the electrochemical cell geometry and configuration on the impedance results were investigated.The most accurate EIS measurements can be made in the 2-electrode cells with active shields where a single arc at high frequencies and a complicated low frequency interfacial impedance feature were observed. When 4-electrode cells were employed, the relative impedances of the sample and the analyzer, geometry and positioning of voltage electrodes, and capacitive coupling between the signal lines introduced two types of impedance measurement artifacts. A capacitive-resistive low frequency load was interpreted as a measurement artifact originating from the voltage electrodes' geometry and positioning.The medium frequency artifact combining resistive, capacitive and inductive features is intrinsic to the experimental setup resulting in a voltage divider effect.

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Electrochemical monitoring of water–surfactant interactions in industrial lubricants

Cited by 53 publications

References 10 publications

Base oil oxidation detection using novel chemical sensors and impedance spectroscopy measurements

Base oil oxidation detection using novel chemical sensors and impedance spectroscopy measurements

Engine oil acidity detection using solid state ion selective electrodes

AC Impedance Characterization of Highly Resistive Media Using Four-Electrode Electrochemical Cells

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