Yanbao Guo

Preparation and hydrophobic behaviours of polystyrene composite coating

A polystyrene (PS)/paraffin wax composite coating with excellent hydrophobic property was prepared on stainless steel strainer using a simple, inexpensive immersion drying method. The thickness and bonding strength of the composite coating were measured. Scanning electron microscopy (SEM) was used to characterise the coating surface of the stainless steel strainer. The effects of the paraffin concentration in the PS composite coating and the drying temperature of the coating were studied. The contact angles for oil and water were investigated. The results indicated that the composite coating on stainless steel strainer obtained the best hydrophobic property under paraffin concentration 5 mg mL− 1 and drying temperature 50°C. The water contact angle reached 154 ± 1°, and the coating of the stainless steel strainer also showed a distinct oleophilic characteristic, which could be used for oil–water separation.

Effects of Microscale Particles as Antiwear Additives in Water-Based Slurries with Abrasives

ABSTRACT Abrasive wear is the dominant cause of tool failure in the process of mining and petroleum/gas drilling. This research investigated the effects of two additives, polystyrene and silicon nitride, on the tribological properties of water-based slurries with silicon dioxide or alumina abrasives. A pin-on-disk configuration was utilized to evaluate the performance of the additives for a steel–steel contact. Experimental results showed that polystyrene particles were able to reduce wear but friction increased simultaneously. On the contrary, silicon nitride particles exhibited excellent performance on both wear resistance and friction reduction. Results in this study indicated that the addition of appropriate additives was able to improve the tribological properties of slurries with abrasives.

Synthesis and tribological properties of CuS/ZnS nanoparticles doped polyelectrolyte multilayers

Abstract Polyelectrolyte multilayer thin films [poly(diallyl dimethylammonium chloride) (PDDA) and poly(acrylic acid) (PAA)] for the synthesis of CuS and ZnS nanoparticles were prepared. The CuS/ZnS nanoparticles in situ synthesised by immersing the PDDA/PAA polyelectrolyte multilayer thin films into Cu2+(or Zn2+) and Na2S aqueous solutions alternately, which were characterised in detail by UV visible absorption spectroscopy, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) analysis. The CuS and ZnS nanoparticles doped polyelectrolyte multilayer thin films were synthesised by the layer-by-layer molecular deposition technology and in situ synthesis method. The coefficient of friction (COF) decreased with the in situ synthesis CuS and ZnS nanoparticles doped into the polyelectrolyte layers. The in situ nanoparticles exhibited enhanced wear resistance performance of the plain polyelectrolyte multilayers.

Tribological Properties of Hybrid Ag4SiW12O40 Nanoparticles Multilayer Films

Inorganic-organic hybrid nanoparticles molecular deposition films were fabricated by extending the method of nucleation and growth of particles in polymer assemblies. Poly (diallyldimethylammonium chloride) (PDDA) and poly (styrenesulfonate) sodium salt (PSS) were applied as polycation and polyanion respectively. At first, PDDA/PSS films were obtained by alternately depositing PDDA and PSS on the cleaned substrate with molecular deposition (MD) method. Then, follow’s alternately dipped the precursor polyelectrolyte multilayer MD films into AgNO3 and H4SiW12O40 aqueous solutions. Repeating the above synthesis process, Ag4SiW12O40 nanoparticles were synthesized in the polyelectrolyte multilayer films in-situ. UV-vis absorption spectra indicate that the Ag4SiW12O40 nanoparticles grew gradually in the synthesis process. The structure and nanotribological properties of hybrid nanoparticles multilayer films were analyzed by atomic force microscope (AFM) and the antiwear life was analyzed by micro-friction and wear test machine. It was found that these films had small friction force and high antiwear life. The MD film had best tribological properties when the cycle number is six. Nanoparticles within the MD films can enhance antiwear life of MD films attributed to nanoparticles possess load-carrying capacity, and decrease the mobility of the polymer chain segments which can undergo reversible shear deformation.

Friction and wear behaviors of sand particle against casing steel

Tools abrasive wear due to sand particles has caused severe damage during oil and gas exploitation. The friction and wear behaviors of single quartz sand particle against N80 casing steel were investigated to estimate the particle transport resistance and particle abrasive wear behavior using a homemade tribometer in wellbore sand cleanout. Various measurements were conducted to research the impact factor of particle under different water processing condition, dry, short immersion, wet, influences of load and slide velocity. Experimental results indicated that particle-casing friction resistance is mainly formed due to plowing and adhesion effect. Casing transfer and plowing removal are two main damage forms. Particle real contact area increases noticeably after water absorption, which decreases the hertz contact stress and finally produces less plowing depth of casing steel and causes less damage. With load increasing, friction resistance and wear increase with addition of plowing depth. A simple particle-casing friction model was established considering the experimental contact behavior.

Mechanical and Unlubricated Sliding Wear Properties of Nitrile Rubber Reinforced with Micro Glass Flake

In this study, the filled nitrile rubber (NBR) was prepared with micro glass flake (GF). The tribological behaviors of filled NBR were tested by a ball-on-disk tribometer. Material properties such as glass transition temperature (Tg), fracture energy, tensile strength and dispersity of GF filler were also investigated. The results showed that the coefficient of friction (COF) of NBR reduced and the wear-resistant enhanced with the GF filler. Compared to unfilled NBR, the COF of filled NBR suffered a maximal drop percent (about 21.1%) at a rotation speed of 100 rpm and normal load of 1.5 N. Mechanical and wear behaviors were dependent on the interfacial performance of filler in the rubber matrix. Filler with smaller size was more conducive to enhance the interfacial strength of the polymer matrix. That can increase the interfacial strength of filler and benefits to improve the anti-wear behavior of rubber.

Removal and tribological behaviors of waxy deposition layer in cleaning process

Purpose The wax deposition in oil wells and pipelines is very viciously negative to the petroleum extraction and crude oil transportation, and it even causes severe blockage accident. This study aims to describe cleaning experiments performed on wax deposition of different deposition layer and experimental conditions to investigate the removal and tribological properties and chip formation. Design/methodology/approach An optical arrangement was used to visually record the cleaning process, whereas the friction forces were measured by a custom-built tribometer. Various measurements were performed with tool rake angles of 45° and −30° and cleaning depths from 1 to 5 mm. Findings Results from experiments and modeling suggest that the transition of chip was dependent on rake angle, wax performance and cleaning depth. While the cleaning depth increased, the friction and cleaning resistant force also increased. With the increase of cleaning depth, the wax layer cleaning quantity increased and the chip strengthened; hence, the curvature radius of chip was enhanced to form platy chip. The chip of wax–oil mixture was discontinuous units, and it was easy to adhere on the rake face with the increasing depth of cut. With an increase in cleaning depth, the friction and cleaning-resistant force also increased. Originality/value It is concluded that for effectively cleaning and stabilizing of pipeline cleaning machine, different cleaning parameters should be applied to accommodate wax layer or wax–oil mixture.

Effects of alternating stray current on the corrosion behaviours of buried Q235 steel pipelines

Purpose With the rapid development of rail transportation and energy-delivery systems, such as buried oil and gas pipelines and high-voltage transmission lines, the alternating current (AC) corrosion of buried steel pipelines is becoming more serious. This paper aims to study the corrosion behaviours of Q235 buried steel pipelines induced by the alternating stray current, with a set of indoor simulated experiment apparatuses. Design/methodology/approach The corrosion of the coating holidays of the buried steel pipelines at various AC current densities from 0 to 200 A/m2 in the soil-simulating environment was revealed by the electrochemical and weight-loss methods. Findings The results showed that the corrosion potential of the steel shifted negatively obviously and the corrosion rate of the steel increased with the increasing of AC current density. At a low AC current density, the negative deviation of the corrosion potential of the steel was small and the increase of corrosion rate was slight. However, the negative deviation of the corrosion potential was remarkable and the corrosion rate was greatly increased at a relative higher AC current density. The geometrical shape of the corrosion images indicated the corrosion forms changed from uniform corrosion to local corrosion due to the increase of AC interference. Originality/value Investigation results are of benefit to provide a new strategy to forecast and evaluate the AC-induced corrosion of the buried pipelines which could improve the safety of pipeline transportation.