Study On Synthesis Of Titanium Borate And Its Extreme Pressure And Anti-wear Properties

Traditional lubricant additives are mostly phosphorus, sulfur, chlorine compounds. These conventional anti-wear additives duo to severe environmental problems can not meet the requirements of society. In recent years, with the development of science and technology, boron containing lubricant additives have received considerable attention due to their high-performance, multi-function, non-toxicity and energy conservation.In this paper, a novel titanium borate was synthesized by using titanyl sulfate and borax as raw materials through a wet chemistry method. The effects of raw material ratio, concentration of borax, reaction time and temperature on the synthesis of titanium borate were investigated, respectively. The optimal synthetic conditions:room temperature, the concentration of borax is1.0mol/L, the concentration of titanyl sulfate is0.9mol/L, Ti:B=1:5(raw material molar ratio), time15～20min. The contents of B2O3, TiO2and H2O in the product were determined through chemical analysis, ICP and TG/DTG. The IR and Raman analyses of the product indicate that there exists a (B2O5)4-unit which contain [BO3] only in the synthesized titanium borate. The calculated molecular formula of titanium borate is (TiO)2B2O5·4H20, and the purity of titanium borate is82%. The synthesized titanium borate was characterized by XRD and SEM, the results show that titanium borate is a amorphous powder with a particle size of1～10μm.Stearic acid and oleic acid were selected as modifying agents to modify titanium borate. The modification results indicate that both stearic acid and oleic acid could improve the lipophilic degree of titanium borate. The suitable modification conditions are:adding5wt%(the mass fraction of solvent) stearic acid and stirring1.5h in water bath of70℃to lead to a lipophilic degree value of88.15%; adding5wt%(the mass fraction of solvent) oleic acid and stirring1.0h in water bath of70℃to result in a lipophilic degree value of77.27%. Titanium borate and modified titanium borate were characterized by XRD, IR and SEM. The XRD result indicates that there was no change of modified titanium borate phase. The IR spectra suggest that stearic acid or oleic acid was adsorbed on the surface of titanium borate powders with monolayer adsorption. Particle sizes of modified titanium borate are smaller than unmodified titanium borate with a uniform particle size distribution.The extreme-pressure and anti-wear properties of150SN base oil, which respectively contains0.1wt%、0.3wt%、0.5wt%、0.7wt%、0.9wt%titanium borate, were evaluated by a four-ball machine. The maximum nonseizure load (PB)of150SN base oil was improved and the spot diameter of grinding for150SN base oil was descended with adding modified titanium borate, indicating that the extreme-pressure, anti-wear properties and load carrying capacity of base oil were improved. When adding0.1wt%of stearic acid-modified titanium borate to lubricating oil, the wear scar diameter is reduced to0.72mm and the maximun non-seizure load is increased to510N. However, when adding0.3wt%of oliec acid-modified titanum borate, the wear scar diameter is reduced to0.44mm; while adding0.9wt%of oliec acid-modified titanum borate, PB value is reached549N, illustrating that the oliec aicd-modified titanium borate have a very significant influence on extreme pressure and anti-wear properties of base oil.