Research On Preparation Of Photodegradable Solid Lubrication Materials For Wheel/Train

Based on the industrial application of solid lubricant, this paper is to research akind of environmental protection materials of solid lubricant. Ttanium dioxide (TiO2)was obtained by the sol–gel method with the assistance of ultrasound. The next step,Ttanium dioxide (TiO2) was modified by adding metal ions. Finally, as photocatalystmodified TiO2and stearic acid metal salt were added in solid lubricant. Our purposeis to develop a photodegradation solid lubricating materials. Then we drew the bestconclusion from the test results.In this paper, Titanium dioxide(TiO2) sols were prepared by the hydrolysis andcondensation of titanium (IV) n-butoxide in ethanol, using tetraisopropyl orthotitanateas Ti-precursor and acetic acid as the inhibitor. Then sols were dried for5h at80℃,and the dry sols were getting for calcining in muffle furnace. After calcining, we gotthe nanometer titanium dioxide. The formulation of Titanium dioxide (the ratio ofwater: anhydrous ethanol: acetic acidbutyl: tetraisopropyl orthotitanate) wasoptimized by orthogonal experiment. The gelation time, opacity of sols, X-raydiffraction, particle size and the degradation of methyl orange were measured andcharacterized. Finally, we can get the best ratio and calcination conditions for titaniumdioxide.Ttanium dioxide (TiO2) was modified by adding metal ions which included Ag+、Zn2+、Cu2+、Mg2+、Fe3+、Ni2+、Sn2+and Ca2+, by the mass ratio of1%. Then themodified nano titanium dioxide was added in the solid lubricating materials by1%(mass ratio). According to the national standard of photodegradation experiment, wemake the sample of solid lubricating. Finally, the elongation at break and carbonylvalue were measured and characterized to get the best modification scheme. Thispaper reaches some conclusions as following：（1）Through orthogonal experiment, we get that the best dosage of H2O is4mol,CH3COOH for0.5mol and CH3CH2OH for10mol when the amount of Ti(OC4H9)4is1mol. Then we could get the sol which has high transparency and good uniformity.（2）On the process of calcining TiO2, the particle size of TiO2could greatlyreduce with the reducing of heating rate. The particle size of TiO2would reduce byhalf when the heating rate is reduced from5℃/min to2℃/min. The calcinationtemperature determines the crystal shape of TiO2. The crystal shape of TiO2rapidly turn into rutile when the calcination temperature is500℃~600℃. So the bestcalcination temperature is500℃. Meanwhile, we get the highest performance ofdegradation when the calcination time of TiO2is2h.（3）Adding TiO2、FeSt3、CeSt4into solid lubricant by the mass ratio of1%, bythe elongation at break the degradation rate of TiO2is16.94%, FeSt3for6.71%andCeSt4for7.82%. While by the carbonyl value the degradation rate of TiO2is15.67%,FeSt3for2.58%and CeSt4for12.13%. Above all, the order of the degradationperformance to solid lubricant is that: TiO2＞CeSt4＞FeSt3.（4）We take a series of dosage between0%-1%(0%,0.2%,0.4%,0.8%1%) toget the best dosage of each photodegradations. With the increase of the amount ofTiO2, the elongation at break of solid lubricant decreased quickly duringphotodegradation. When the dosage of TiO2is1%by mass ratio, we get the biggetdegradation rate by16.94%. With the increase of the amount of FeSt3between0%to0.8%, the elongation at break of solid lubricant decreased quickly. But the degradationrate by the amount of1%(6.71%) is almost equal to0.8%(6.69%). So we change0.8%to be the best dosage of FeSt3. The elongation at break as well decreased quicklywith the increase of the amount of CeSt4, the best dosage of CeSt4is1%by massratio.（5）After modified by Cu2+、Mg2+、Fe3+、Ni2+、Sn2+、Zn2+and Ca2+, thedegradation performance of TiO2has been improved but also reduced. The metal ionsof Cu2+、Mg2+and Ni2+have reduced the degradation performance of TiO2. On theother hand, the metal ions of Fe3+、Sn2+、Zn2+and Ca2+have improved the degradationperformance of TiO2especially Zn2+. The degradation rate of Zn2+/TiO2is21.36%(toTiO216.94%). Finally the order of metal ions to improve the degradationperformance of TiO2is that: Zn2+/TiO2＞Fe3+/TiO2＞Sn2+/TiO2＞Ca2+/TiO2＞Cu2+/TiO2＞TiO2＞Mg2+/TiO2＞Ni2+/TiO2.