Heat Transfer Over A Finite Distance Using A Fluid Medium (Liquid/Gas) Is A Routine Affair In Several Engineering Applications Like Heat Exchangers, Refrigerators, Automobiles, Power Plants, Etc. Since Thermal Conductivity Of Solids Is Orders Of Magnitude Greater Than That Of Liquids, Dispersion Of Solid Particles In A Given Fluid Is Expected To Increase Its Thermal Conductivity. However, Dispersion Of Milli- And Micrometer-Sized Particles Is Prone To Sedimentation, Clogging And Erosion Of Pipes And Channels. In Contrast, Nanofluid Is A Stable Colloidal Suspension Of Low (<2%) Volume Fraction Of Ultra-Fine Solid Particles In Nanometric Dimension Dispersed In Conventional Heat Transfer Fluid To Offer A Dramatic Enhancement In Conductivity Of The Fluid Without The Above-Mentioned Problems Encountered In Dispersing Coarse Particles. Despite Several Attempts, The Precise Mechanism For This Significant Enhancement Is Not Yet Established. Hence, Continued Efforts Are Warranted To Synthesize Different Types Of Nanofluid And To Study Its Heat Transfer Characteristics. In The Present Study, Al-30 At % Cu (Al2Cu) And Al-30 At % Ag (Ag2Al) Dispersed Water/Ethylene Glycol Based Nanofluids Were Prepared By A Two-Step Method, In Which The Nanometric Al2Cu And Ag2Al Particles Were First Produced By Mechanical Alloying Of Elemental Powders In Appropriate Proportion Using A High Energy Planetary Ball Mill With WC Media At 10:1 Ball To Powder Weight Ratio, Followed By Dispersing These Submicron Solid Particles Into The Base Fluids (Water And Ethylene Glycol) To Produce Nanofluids With Different Levels Of Solid Dispersion. The Particle And Grain Sizes Of The Milled Product Were Varied By Milling Up To Different Hours. Another Set Of Water/Ethylene Glycol Based Nanofluid Was Prepared By Using Spherical 3 Mol.% Y2O3 Partially-Stabilized Nanometric Zro2, Al2O3 And Tio2 Nanoparticles. Studies With Metallic And Ceramic Nanoparticle Dispersed Nanofluid Were Designed To Investigate If Chemical Bonding Of Dispersoid Would Influence The Level/Extent Of Enhancement Of Thermal Conductivity Of Nanofluids. Identity And Particle/Crystallite Size Of The Phases Were Determined By X-Ray Diffraction And Verified By Transmission Electron Microscopy. Solid Particles Were Deagglomerated And Homogenized In Nanofluids By Adding An Appropriate Surfactant (1 Vol.% Oleic Acid/Tetramethyl Ammonium Hydroxide ((CH3)4NOH, TMAH) And Intensive Ultrasonic Vibration And Magnetic