The Preparation Of Phosphotungstic(Phosphomolybdic) Acid Ammonium Ultrafine Particles And Their Tribological Performance In Water

In this paper, polyvinylpyrrolidone(PVP) modified phosphotungstic acid ammonium ultrafineparticles, PVP modified ammonium phosphomolybdate ultrafine particles and triethanolammoniumphosphomolybdate were prepared. The structure and morphology of the samples were characterized bymeans of X-ray powder diffraction(XRD), thermogravimetric analyzer(TG), Fourier transform infraredspectrometer(FT-IR) and scanning electron microscope(SEM) and so on; The samples were dispersed intowater system and the water-based tribological performance of as-obtained samples were investigated on anMSR-10A four-ball apparatus; The elements of worn steel surface were analysed by means of X-rayphotoelectron spectrometer(XPS) to speculate the possible tribological mechanism. The main researchcontents and results were as follows:1. The preparation of PVP modified phosphotungstic acid ammonium ultrafine particles and the studyof their tribological performance in water.The PVP modified phosphotungstic acid ammonium ultrafine particles were prepared usingphosphotungstic acid and urea reaction by homogeneous precipitation method. The structure of thesamples were characterized by XRD and FT-IR, which proved that the products were phosphotungstic acidammonium with Keggin structure; Laser particle size analyzer was used to examine the influence about thedosage of PVP dosage and the concentration of phosphotungstic acid on the particle size ofphosphotungstic acid ammonium and determine the best reaction conditions; The morphology and thestructure of the samples prepared in the best reaction conditions were characterized by means of SEM andTG, which proved after PVP modification, the morphology of the samples were changed to balls, the particle size decreased to200nm and there were about0.79%PVP in the samples; The tribologicalperformance of the samples in water was investigated by an MSR-10A four-ball apparatus, the resultsshowed that PVP modified phosphotungstic acid ammonium ultrafine particles as a new kind ofwater-based lubricant additives had good anti-friction and anti-wear effect, when the load was50N,compared with pure water, the friction coefficient could be reduced by55%, the anti-wear performancecould be increased by52%, the bearing capacity of water could be increased from less than100N to300N;The elements of worn steel surface were analysed by means of XPS to speculate the possible tribologicalmechanism, the results showed that iron oxide, tungsten oxide, iron nitride and tungsten nitride may formin the worn steel surface as the main part, so the anti-friction and anti-wear properties of the samples weregood.2. The preparation of PVP modified ammonium phosphomolybdate ultrafine particles and the study oftheir tribological performance in water.In this chapter ammonium phosphomolybdate particles were synthesized in water using PVP as themodified agent by phosphomolybdic acid and ammonium chloride with precipitation method, and thewater-based tribological performance were studied. The structure of the samples were characterized by theXRD, TG and FT-IR, the results showed that the samples prepared were the ammonium phosphomolybdatewith Keggin structure, there were about4.98%PVP in the samples; The morphology of the samples werecharacterized by SEM, which proved after PVP modification, the morphology of samples were changed toballs, and the particle size was about500nm or so; The tribological performance of the samples in waterwas investigated by an MSR-10A four-ball apparatus, the results showed that PVP modified ammoniumphosphomolybdate ultrafine particles as a new kind of water-based lubricant additives had goodanti-friction and anti-wear effect, when the load was50N, compared with pure water, the friction coefficient could be reduced by68%, the anti-wear performance could be increased by43%, the bearingcapacity of water could be increased from less than100N to300N; The elements of worn steel surfacewere analysed by means of XPS to speculate the possible tribological mechanism, the results showed thatiron oxide, molybdenum oxide, iron nitride and molybdenum nitride may form in the worn steel surface asthe main part, so the anti-friction and anti-wear properties of the samples were good.3. The preparation of triethanolammonium phosphomolybdate and the study of their tribologicalperformance in water.In this chapter triethanolammonium phosphomolybdate were synthesized using phosphomolybdicacid and triethanolamine by precipitation method, and the water-based tribological performance werestudied. The structure of the samples were characterized by XRD, TG and FT-IR, the results showed thatthe samples prepared were likely to triethanolammonium phosphomolybdate; The morphology of thesamples were characterized by SEM, which proved that the morphology of samples were irregular lamellarstructure; The tribological performance of the samples in water was investigated by an MSR-10A four-ballapparatus, the results showed that the as-obtained samples as a new kind of water-based lubricant additiveshad good anti-friction, when the load was50N, the friction coefficient could be reduced by76.6%compared with pure water, but the anti-wear effect of the material was not significant, No ultrafineparticles in the water was the possible reason; The elements of worn steel surface were analysed by meansof XPS to speculate the possible tribological mechanism, the results showed that iron oxide, molybdenumoxide, iron nitride and molybdenum nitride may form in the worn steel surface as the main part, so theanti-friction properties of the samples were good.