Study On Theanti-fouling, Anti-wear, Anti-static Properties Of Composite Coating Applied To Screw In The Circumstance Of ASP

In view of the problems of higher starting torque, huge energy consumption, easily scaling, poor wear resistance, and short pump inspection cycle, etc, existing in the operation of chrome-plated progressing cavity pump (PCP) rotor in ASP flooding production, and according to the relationship between the solid surface and the dirt deposition and the feature that the PCP rotor produces static electricity easily when the PCP rotor surface is rubbing against the stator rubber, and by means of plasma spraying, the anti-fouling, wear-resistant, and anti-static ceramic composite coating was obtained with AT13 (Al2O3+13%TiOa) as matrix which has the properties of anti-fouling, good wear resistance and low surface energy, and doped with antifriction powder MoS2, antistatic nanopowders ATO(antimony tin oxide-antimony doped tin oxide), and multi-doped of MoS2 and ATO. And those studies included the composition design of ceramic coating, the investigation on thermal spray technology, the performance tests of composite coatings’anti-fouling, anti-static, anti-friction and wear resistance, and the field-test research.By means of modern physical chemistry and instrumental analysis method, the anti-fouling, anti-static, anti-friction wear resistance performance of AT13+MoS2, AT13+ATO and ATI3+MoS2+ATO coatings have been measured, including microhardness, adhesive strength, thermal shock resistance, coatings density and porosity, etc. The structure of coatings has been studied by SEM, DES and XRD. The research results are shown as below:The porosity of the composite coatings increases, while the density and adhesive strength decrease with the increasing MoS2 levels. With the addition of ATO, the density, porosity, adhesive strength and thermal shock resistance of coatings are similar with AT 13 on account of the powder’s nanometer effects. As a result of the combined effect of MoS2 and ATO, the coating properties have been changed with the adding of MoS2 and ATO.Through the performance tests about composite coatings’anti-fouling, anti-corrosion, anti-wear and anti-static,the anti-friction and anti-static mechanism of MoS2 and ATO in the composite coatings have been analyzed. The adding of MoS2 reduced the friction coefficient of the coatings, thus improved the antifriction properties, and the adding of ATO has dramatically improved the electric conductivity of the composite coating, so as to obtain the anti-static performance.Combined with the microstructure and performance analyses, the coatings with superior performance have been screened:the antifriction coating (AT13+6wt%MoS2), the anti-static coating (AT13+10wt%ATO), and the composite coating with a superior performance of antifriction and anti-static (AT13+6wt %MoS2+10wt%ATO).Under the same environmental condition, deceasing surface energy of the scaling surfaces and increasing surface roughness can reduce the amount of scaling, and thenobtained the anti-fouling purpose. The low-surface-energy ceramic composite coating, which is adding of MoS2 and ATO, plasma spraying on the surface of PCP pumps, decreasing the surface energy of the solid materials. Due to the leading role of MoS2 and supplementary effect of nano ATO, AT13+6wt%MoS2+10wt% ATO composite coating has the best anti-wear property.The plasma spraying experiments of three coatings on rotor have been studied by the equipment of the thermal spray copying machine designed by own. The roughness grade of rotor’s surface, processed by plasma spraying and polished by diamond sandpaper, is more than Ra=0.25 pm, and the hydraulic characteristics test indoor with pump shows a good effect. Especially the rotor with a composite coating of AT13+ 6wt%MoS2+10wt% ATO achieves an energy efficiency effect with a small start torque, long pump inspection cycle, and finds a new path to improve efficiency for the PCP’s application in the complex environment of ASP flooding.In the oil field application process, the rotorwith composite coatingexhibits excellent anti-scaling propertyand anti-wear property, and solves the problem of scaling and wear of conventional rotor. Meanwhile the supporting high technologies, such as small interference fit and high ebonite pumps, can effectively decrease the operating torque of PCP pumps. All of these have increased the adaptability of PCP pumps and extend pump inspection periods.