## 1 Introduction  
Increasing demand for resources gives us an opportunity to concentrate on sustainable development, and this is not possible without considering all the aspects associated with a system. For automobile and mechanical industries where mating surfaces are used to transfer maximum energy, it is important to reduce both wear and friction, which results in less energy consumption and longer functional life for moving mechanical components in machinery [1]. This can be achieved by making surfaces frictionless or by developing better lubricants that do not just control friction and wear but reduce clotting, oxidation, foaming, and corrosion problems in hydraulic systems [2]. Advancement in nano technology allows researchers to implement different manufacturing processes and evaluate applications of nano materials in a variety of fields. In the past researchers have tried nano additives such as metal [3], metal oxide and sulfide [4; 5] organic-inorganic material [6], carbon based materials [7; 8; 9], and ionic materials [10] in different lubricants. These additives have shown positive effects on lubrication characteristics due to high surface area, higher diffusion rate, and small particle size. A higher diffusion rate allows lubricants to reduce micro friction, which leads to reduced wear and heat concentration in machining processes [11]. Titanium and its oxides from macro to nano scale are widely used by different industries because of their high strength, corrosion resistant nature, bio compatibility, and cost effectiveness [12; 13]. For example, titanium powder is used by the marine, aeronautical, chemical, paint, and machinery industries to prevent rust and improve strength without adding more weight to the structure [12; 14]. Sunscreen lotion contains a high amount of titanium dioxide to protect the skin from UVB and UVA2 rays [14; 15]. However, titanium has a bad reputation in terms of sliding tribology, due to unstable friction and wear, and higher chances of seizing [12; 13]. As per stability tests and microscopy findings, 36% of nano particles should be smaller than 100 nm for high dispersibility in the water [15]. In addition, studies show that TiNP produces thick and rutile film on the substrate, which can be used for rustproofing applications in tribology [16]. Graphene allotropes are joined in hexagonal shapes, which are basic structures to form carbon based materials. Carbon based materials are synthesized in versatile structures with different physical and chemical properties; thus, they have the potential to be used for different applications such as energy storage, sensors, cancer phototherapy, and electromechanical devices [17; 18; 19; 20]. Graphene can be produced by different methods such as chemical reduction and thermal treatment by Hummer's method [21]. However, in all these methods, there is a possibility of damaging the lattice of the carbon. Also, using toxic oxidizers can result in negative effects on the environment and increase fabrication costs. Finally, greater lattice defects from graphene can have adverse effects on tribology improvement [22]. Studies have proven that graphene multilayer nano additives can be used in engine oil, bentone grease, and hydraulic applications to improve tribological and thermal properties [23; 24; 25]. However, graphene produced using different methods has shown diverse effects as a tribo improv. In this paper, the tribological effects of graphene nano platelets (GNP) and titanium nanopowders (TiNP) individually and together on the friction and wearability of both liquid and semi-liquid lubricants were studied. In the first phase, the liquid-base lubricants were tested at 0.01% _w/w_, 0.05% _w/w_, and 0.1% _w/w_ concentrations for each additive. It was found that GNP plays an important role in controlling the coefficient of friction (COF); however, adding TiNP results in lower wear under test conditions.