Study on the anti-wear properties of metal-forming lubricants with TiO2 and CuO nanoparticle additives

The metal-mechanic industry is intensive in operations of transformation of materials that demand a high energy consumption to overcome the coefficient of friction (COF) generated in the manufacturing process. One of the most demanding processes is the deep drawing forming process of chassis for the automotive industry. Every day more resistant and lighter steels are developed with the aim of contributing to the efficiency in the use of fuel. The problem is generated by having a speed of development of structural steels greater than that of tool steels; these (tool steels) suffer the consequences: wear and fractures as well as increases in the COF. Currently, the aim is to reduce the coefficient of friction and the wear generated by several technologies: a) surface engineering with coatings, surface thermal treatments and laser texturing among others. b) In addition, work is being done to produce lubricants that are more efficient and to reduce the COF and wear to the maximum. It is well known that lubrication is essential for protecting moving surfaces against friction and wear in metalworking applications. Nanotechnology is a science that is improving the tribological performance of lubricants in big leaps through the addition of nanoparticles in concentrations ranging from 0.01 wt.% to 2 wt. %. In this work one metal-working polymeric lubricant with viscosity of 529 Cst, was treated with varying wt.% (0.01, 0.05 and 0.1) of CuO and TiO2 nanoparticle additives. Antiwear properties of wear scar diameter (WSD) and coefficient of friction (COF) were characterized with a four-ball T-02 tribotester according to ASTM D 5183 and with a ball-on-disk apparatus. The dispersion method used for combining nanoparticles and lubricant also is explained. Nanoparticle additives showed an overall improvement of the tribological properties of polymeric lubricant. An important improvement of anti-wear properties for CuO at 0.05 wt.% and TiO2 at 0.01 wt.% of 33% and 77%, respectively, (WSD improvement) were obtained demonstrating the potential of nanolubricants for improving the efficiency of mechanical components. This work in addition to showing the improvements found presents the possible tribological mechanisms that explain the anti-wear behavior obtained in the laboratory.