Advanced Processes and Systems in Manufacturing An International Conference 2016 28 ~ 30 August 2016- Kuala Lumpur, pp. X-X

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Adding Nano Titanium Dioxide Anatase and Graphene to Base Oil Group II for Lubrication Optimization

Waleed Alghani1, Mohd Sayuti Ab Karim1*, Samira Bagheri2, Nor Amirah Mohd Amran1

1)Department of Mechanical Engineering,

Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia.

2)Nanotechnology & Catalysis Research Centre, IPS Building, University of Malaya, 50603 Kuala Lumpur, Malaysia.

*Corresponding e-mail: mdsayuti@um.edu.my

Keywords: Nano tribology; Solid lubricant additives; Energy consumption. ABSTRACT – In the present study nano particles titanium dioxide anatase TiO2 (A) + graphene have added into the base oil group two (BO G II) for enhancing the tribology properties in term of anti friction & wear and surface morphology improvement. Oleic acid OA surfactant/precursor was blended with the formulation to stabilize the nano particles into the lube oil. One type of precursors (OA) has used with the formulation due to its properties and for cost saving aspect. Next to that oleic acid is unsaturated fatty acid to improve the nano particles dispersion into the base oil and for lubricity improvement as well. Four-ball tester has employed to examine the tribological performance for six different formulated samples. Moreover, image acquisition system was used to calculate the scar wear diameter. Furthermore, Phenom ProX ultimate imaging desktop was utilized for scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDX) to identify the metallographic characterization of the surface. The novelty of this work is formulating two smart nano particles TiO2 (A) + graphene with the industrial base oil group II to improve the lubrication specifications. Experiments proved that adding 0.04wt% TiO2 (A) + 0.02wt% graphene to the base oil G II have optimized the tribology behavior. The upgraded tribological performance of TiO2 (A) and nano graphene with BO G II can be attributed to the superior structural integrity of the mixture and the created transfer film of the nano TiO2 (A) + graphene during the sliding motion process. 1. INTRODUCTION

Friction, the action of one surface rubbing against another, hence sufficient energy will be consumed to overcome this force. A lot of researches done to reduce the friction in order to save the energy, beginning from using water and mud till oil with additives as a lubricant [1]. Current studies are to improve the lubricant performance by adding nano particles for friction reduction, anti wear, less scar wear diameter, low friction coefficient and even enhance the carrying load capacity & extreme pressure in some applications [2], [3], [4] & [5]. Titanium dioxide (TiO2) or Titania is a very well known and well-researched material due to the stability of its chemical structure, biocompatibility, physical, optical, and electrical properties. It exists in three mineral forms viz: anatase, rutile, and brookite.

TiO2 Anatase type has a crystalline structure that corresponds to the tetragonal system (with dipyramidal habit). Generally, TiO2 is preferred in anatase form as a metal oxide additive because of its high specific area, non-toxic, relatively inexpensive, better dispersion of the formulation, barrier properties in the coatings, self-healing effect giving advantage in anticorrosion behavior [6]. TiO2 nanoparticles revealed superior anti friction and anti wear characteristics [7]. Nano graphene becomes the material of the century because of its superb characteristics in the term of physiochemical properties in tribology applications. Whilst graphene is two-dimensional material, presents exclusive friction and wear properties that are not usually seen in conventional materials. Moreover its well-established thermal, electrical, optical, and mechanical properties, graphene can function as a solid or colloidal liquid lubricant. Its high chemical inertness, extreme strength, and easy shear capability on its thickly packed and atomically smooth surface are the key positive attributes for its remarkable tribological behavior [1]. However, the tribological properties of these nano combination materials remain incompletely understood. In this work, the nano materials prepared and their tribological properties were examined. The synergistic lubrication effect of nano platelets graphene and nano TiO2 Anatase was also investigated. The nano graphene + TiO2 Anatase were found to be promising lubricant additives with better performance than pure base oil group II. 2. METHODOLOGY

Six samples have been examined in Four Ball Tester TR-30 Ducom by using SKF steel balls 12.7 mm diameter. Titanium (IV) oxide, Anatase <25 nm particle size, 99.7% trace metals basis and Graphene nano platelet ~ 5nm thickness with surface area 120 m2/g. The base oil group II was brought from GS Caltex a South Korean oil refiner. ThisbaseoilgroupIIaccordingtotheAPIclassificationisusedforthisstudy.Oleic acid C18H34O2 extra pure M.Wt 282, 46 g/mol have used for this study. Formulation of each sample is shown in Table 1. After preparing the six samples, sonication for 5 samples have done for 2 hours at 80°C temperature except the pure oil sample. This ultrasonic treatment in order to assure the formation of a stable suspension of previously dispersed nanoparticles into the base oil [8]. Table 1: State the quantities of the nano particles and the

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oil used in this study TiO2 (A)mg

Graphenemg

Base OilGIIml

OleicAcidml

0.0 0.02 8 2 0.02 0.0 8 2 0.02 0.02 8 2 0.02 0.04 8 2 0.04 0.02 8 2 0.0 0.0 10 0 The 4 balls tribotester was calibrated on 75°C temperature, speed rotation 1200 RPM and constant load 392 N/ (40 Kg) according to the ASTM D 4172 B the standard test method for wear preventive characteristics of lubricating fluid. 3. RESULTS AND DISCUSSION

The synergistic lubrication effect of nano TiO2 Anatase and nano platelets graphene revealed profitable results in term of coefficient of friction COF µ, scars wear diameter SWD µm, wear rate WR m3/Nm. Due to the superior sturucture of the formulation and the transfer film that created during the friction process that secured the ball surface [9]. As itemized below:

I. Coefficient of Friction behavior

Figure 1: Shows the differences in COF µ among six types of concentrations.

II. Wear Rate behavior

Figure 2: Shows the differences in wear rate (x10-16) m3/Nm with respect to 1 hour Time for six types of concentrations.

III. Metallographic characterization

Figure 3: SEM & EDX characterization for steel ball surface after submerging it with 0.04wt% TiO2 (A) + 0.02wt% Graphene + Base Oil Group 2 Lubricant. 4. CONCLUSIONS

Formulating of 0.04wt%TiO2 (A) + 0.02wt% graphene with base oil group two were observed the best rates to acquire profitable results. The synergetic superior structure of the blended lubricant remarkably diminished the COF, SWD and WR. The creation of the tribofilm has protected the ball surface from the severe friction and adhesion wear.

5. REFERENCES

[1] Diana Berman, A.E., Anirudha V. Sumant. Graphene: a new emerging lubricant. Materials Today, 2014. 17(1). [2] Juozas Padgurskas, R.R., Igoris Prosycˇevas, Raimondas Kreivaitis, Tribological properties of lubricant additives of Fe, Cu and Co nanoparticles. Tribology International, 2013. 60: p. 224–232. [3] Xianbing Ji, Y.C., Gaiqing Zhao, Xiaobo Wang and Weimin Liu, Tribological Properties of CaCO3 Nanoparticles as an Additive in Lithium Grease. Tribology Letters, 2011. 41: p. 113–119. [4] Bon-Cheol Ku, Y.-C.H., Jung-Eun Lee, Jae-Keun Lee, Sang-Ho Park and Yu-Jin Hwang, Tribological Effects of Fullerene (C60) Nanoparticles Added in Mineral Lubricants According to its Viscosity. International Journal of Precision Engineering and Manufacturing 2010. 11(4): p. 607-611. [5] Kwangho Lee, Y.H., Seongir Cheong, Youngmin Choi, Laeun Kwon, Jaekeun Lee, Soo Hyung Kim, Understanding the Role of Nanoparticles in Nano-oil Lubrication. Tribology Letters, 2009. 35: p. 127–131. [6] D. P. Macwan, P.N.D., Shalini Chaturvedi., A review on nano-TiO2 sol–gel type syntheses and its applications. Journal of Materials Science, 2011. 46: p. 3669–3686. [7] Yuh-Yih Wu, M.-J.K., Using TiO2 nanofluid additive for engine lubrication oil. Industrial Lubrication and Tribology, 2011. 65(6): p. 440 - 445. [8] S.M. Alves, B.S.B., M.F. Trajano, K.S.B. Ribeiro, E. Moura., Tribological behavior of vegetable oil-based lubricants with nanoparticles of oxides in boundary lubrication conditions. Tribology International, 2013. 65: p. 28–36. [9] A. Moshkovith, V.P., I. Lapsker, N. Fleischer, R. Tenne and L. Rapoport, Friction of fullerene-like WS2 nanoparticles: effect of agglomeration. Tribology Letters, 2006 24(3).

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