Minia Journal of Engineering and Technology, (MJET) Vol. 33, No 1, January 2014 188 RHEOLOGICAL BEHAVIOR OF CARBON NANOTUBES LITHIUM GREASE COMPOSITE Alaa Mohamed a , A. Khattab b , T.A. Osman b , M. Zaki a a Production Engineering and Printing Technology Department, Akhbar El Yom Academy, Giza, Egypt. b Mechanical Design and Production Engineering Department, Cairo University, Giza, Egypt. Abstract: The aim of this work is to study the rheological behaviors of carbon nanotubes (CNTs) as an additive on lithium grease at different concentrations. The results indicated that the optimum concentrations of the CNTs was 2 %. These experimental investigations were evaluated with a Brookfield programmable Rheometer DV-III ULTRA. The results indicated that the shear stress and apparent viscosity increase with the increase of CNTs concentration. The microstructure of CNTs and lithium grease was examined by high resolution transmission electron microscope (HRTEM) and scanning electron microscope (SEM). The results indicated that the microscopic structure of the lithium grease presents a more regular and homogeneous network structure, with long fibers, which confirms the rheological stability. مستخلص: ال ΔيήيتϣϮϧاϨ الϥϮبήيب الكابϧ أΔجيϮلϮيή الιاϮΨ الΔاسέΩ Ϯϫ Δسالή الϩάϫ Ϧϣ سيئيήف الΪϬ ال ήع تغييϣ ϡϮثيϠ الϡϮ شحϰ الΔافπϤ الΔيήيتϣϮϧاϨ الϥϮبήيب الكابϧسب أϧ . لπ افϥ أϰتائج إلϨ الΕέ أشا ΔيήيتϣϮϧاϨ الϥϮبήيب الكابϧ أΔΒسϧ Ϯϫ 2 ٪ . ή بαقياϣ يقήρ Ϧ عιاϮΨ الϩάϫ Ϣ تقييϢ تΪقϭ ΪϠكفيϭ .ΔيήيتϣϮϧاϨ الϥϮبήيب الكابϧ أΰكيή تΓΩياί عϣ ΔجϭΰϠ الΓΩياίϭ κ القΩاϬ إجΓΩياί ϰتائج إلϨ الΕέ أشا Ϊقϭ Ϣ تقييϢ تΔيήيتϣϮϧاϨ الϥϮبήيب الكابϧ أΔيήϬجϤ الΔيϨΒ الϭ ϡϮيثيϠ الϡϮحθ لϯίاϬيق جήρ Ϧ ع ήϬجϤ اليϧϭή اإلكتϭ Ϫلعالي اΔقΪ الΕاΫ ήϬجϤ اليϧϭή اإلكت.ϰئϮπسح الاϤ الήيθتϭ ϰا إلπئج ايتاϨ ال έاήح استقϨϤي تالتϭ ΔϠيϮρ أليافΕاΫϭ Δسϧتجاϣ ϭ اϣتظاϧ اή أكثϡϮيثيϠ الϡϮحθ لΔيήϬجϤ الΔيϨΒ الϥ أ .ΔجيϮلϮيή ال Keywords: Carbon nanotubes, Rheological behavior, Lithium grease, Microstructure.