GREASES
Incorporating nanoparticles into dielectric greases
Dr. Raj Shah, Director, Koehler Instrument Company
Mr. Daniel Baek, Student Intern,
Koehler Instrument Company
Dr. Steve Nitodas, Faculty of Chemical Engineering, Stony Brook University
Introduction
As the automotive industry shifts towards electric vehicles (EVs) to address environmental concerns and reduce dependency on fossil fuels, there is a growing demand for innovative solutions to enhance the performance and reliability of EV components. Dielectric greases play a crucial role in ensuring the efficient operation of electrical systems within EVs by providing electrical insulation, corrosion protection, and lubrication. However, traditional dielectric greases may face challenges in meeting the rigorous demands of EV applications, including elevated temperatures, heavy electrical loads, and mechanical stresses [1].
This article explores the potential of incorporating nanoparticles into dielectric greases to enhance their insulative properties and suitability for use in EVs. Nanoparticles, such as nano-SiO2
and nano-TiO2 [2],
offer promising opportunities to improve mechanical strength, and dielectric performance of greases due to their unique size-dependent properties. Moreover, nanoparticles can mitigate issues such as thermal runaway, which is critical in high-power EV systems.
AC breakdown voltage AC breakdown voltage (BDV) is relevant in applications of dielectric greases because of dielectric greases being placed on battery terminals on high-energy systems. Having greases that can sustain high voltages improves longevity and performance. The goal of adding nanoparticles into dielectric greases is to increase BDV, therefore increasing the threshold where breakdown occurs [3]. Fe2 SiO2
O3 and
nanoparticles were dispersed in natural ester oil in a paper by Charalampakos et al. As seen in Figure. 1, oleate-coated colloidal magnetic iron oxide nanocrystals (colNF) resulted in an increase in breakdown voltage of the dielectric grease as their weight percent increased, exceeding the mean BDV. A slight increase was observed in the silica nanofluid (sNF) with the increase in its weight concentration, even though sNF did not exceed the mean BDV. In addition, it was also observed that at higher weight concentrations for both colNF and sNF, BDV significantly dropped. Due to the high BDV dropping at higher concentrations, the fluid must be optimised to ensure adequate performance.
Continued on page 16 LUBE MAGAZINE NO.186 APRIL 2025 15
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