Synthesis Of Porous Manganese Oxide And Its Tribological Properties Investigation

In this paper, the synthesis process of the layer(OL) and porous(Mg-OMS-1) structure of manganese oxide is optimized, and the rule of the synthesis of porous manganese oxide materials were systematically study by hydrothermal method. Also, XRD、TG-DSC、SEM and FT-IR analysis methods were used to characterize the physical-chemical properties of the samples. And the applications of the layered structure of manganese oxide materials were explored in the field of lubrication. The main research contents and conclusions are as follows.1、In KOH- Mn2+- H2O2 system, the sample of K-OL has been directly synthesized by hydrothermal method. The result shows that the purity of the sample is affected by the stirring time before crystallization. If not stirring or stirring time is too short, the products is a mixture of K-OL and Mn3O4, the pure of K-OL was obtained until stirring time arriving at 6 h. The optimum molar ratio of synthesis is KOH : H2O2 : MnAc2 = 12 : 10 : 1, the crystallization temperature is 150℃ and the crystallization time is 48 h.2、In NaOH- Mn2+- H2O2 system, according to the synthesis of K-OL, the sample of Na-OL also has been directly synthesized by hydrothermal method, the stirring time setted for 6 h. The result shows: the optimum molar ratio of synthesis is NaOH : H2O2 : MnAc2 = 20 : 10 : 1, the crystallization temperature is 150℃ and the crystallization time is 48 h.3、In LiOH- Mn2+- H2O2 system, according to the synthesis of K-OL, the sample of Li-OL has been directly synthesized by hydrothermal method, the stirring time setted for 6 h, The result shows that, the optimum molar ratio of synthesis is LiOH : H2O2 : Mn Ac2 = 3 : 7 : 1, the crystallization temperature is 50℃ and the crystallization time is 48 h.4、The lubrication performance of the base oils liquid paraffin were investigated after adding different mass fraction of Li-OL/Na-OL/K-OL(0.5 wt.%、1.0 wt.%、1.5 wt.%、2.0 wt.%). The results show, in the aspect of bearing capacity, when(1.0 wt.%) K-OL was added to liquid paraffin, the maximum nonseizure lord(PB) value was improved from base oil 431 N to 510 N, which indicating PB was enhanced. In terms of anti-wear performance, when 1.0 wt.% of Na-OL was added to liquid paraffin, its wear scar diameters(WSD) was reduced from base oil 0.62 mm to 0.48 mm, which indicating anti-wear performance of Na-OL(1.0 wt.%) was improved.5、In addition, the tribological properties of the base oils polyethylene glycol 200 were studied after adding the same concentration of Li-OL/Na-OL/K-OL(1.0 wt.%). The experimental results show, in the aspect of bearing capacity, when(1.0 wt.%) Li-OL/Na-OL/K-OL sample was added to PEG200, respectively, PB value is still hold on 549 N, which indicating the base oil bearing capacity did not improve; In terms of anti-wear performance, when(1.0 wt.%) Na-OL/K-OL is added to PEG200, respectively, its wear scar diameters(WSD) is smaller than pure PEG200, and after adding(1.0 wt.%) Li-OL to PEG200, its wear scar diameters is larger than PEG200, the experiment results show that the anti-wear ability of Na-OL/K-OL is better than Li-OL. The friction coefficient of oil products after adding Li-OL is lowest than others, the results show that Li-OL sample have improvement in anti-friction performance. In addition, the tribological properties of Li-OL/Na-OL/K-OL(3.0 wt.%) sample as solid lubricant added to the lithium grease were evaluated by four-ball tester, respectively. Experimental results indicated that, the PB value of lithium grease increased from base grease 353 N to Li-OL 392 N, Na-OL 549 N, and K-OL 441 N, respectively, which indicating the improvement of Na-OL was most remarkable; the PD value of lithium grease increased from base grease 1235 N to Li-OL 1568 N, Na-OL 1568 N, respectively. But the anti-friction and anti-wear properties of lithium grease are not improved after adding these three materials.6、The doped Mg2+ of K-OL, as a precursor, was used to synthesis Mg-OMS-1 in hydrothermal system Mg(NO3)2- H2 O. The result shows that, the reaction temperature have an important influences on the phase transformation. If the temperature is below 220℃, and it will not be able to achieve K-OL to Mg-OMS-1.