Synthesis of γ-AlOOH Nanoparticle and Its Tribological Properties as Additives in Liquid Paraffin

An experiment procedure was presented for the synthesis of γ-AlOOH nanoparticles by a dehydration process which employed the solution of H₂O₂ as dehydrator. The phase and morphology of the product were investigated by XRD and TEM. The tribological properties of γ-AlOOH nanoparticles with the average diameter of 15?nm as additives in liquid paraffin were investigated by a four-ball tester, and the worn surfaces were analyzed by SEM and EDS. Results show that the average size of synthesized γ-AlOOH nanoparticles increases with the increase of the pH value and temperature of the reactant. The γ-AlOOH nanoparticles as additives could exhibit good tribological properties due to their covering effect, which prevents the direct contact of asperities and reduces the adhesion. As the real area of contact decreases with the decrease of applied load, the optimum concentration varies from 0.4% to 0.1% when the applied load decreases from 294?N to 200?N.