Hydraulic oils, hydraulic liquids, or hydraulic fluids is a major part of hydraulic systems, through which power is conveyed in hydraulic equipment. Hydraulic liquids are primarily used in conveying kinetic and potential energy in a hydraulic system. Hydraulic liquids generally provide a flow of volume in hydrostatic motors and pumps. Hydraulic fluids also help in decreasing the wear and tear of parts involved in friction in the piston assembly. Hydraulic fluids also protect the internal systems from corrosion and erosion caused by external environments. Functions of hydraulic fluids have changed by a great magnitude in the last few years. Hydraulic systems are designed to function optimally during the operations at high temperatures, high pressures, and different complex circumstances. Ordinary hydraulic fluids are primarily made of mineral oils and water, which offer very less compressibility and flexibility of usage. Demand for various types of hydraulic systems is increasing constantly, as the modern industry requires high speed and efficiency at higher operating pressures and temperatures. Hydraulic fluids are developed to perform tasks such as lubrication, energy transmiss...