Materials Science Forum Vol. 1026

Abstract: This paper emphasises the effect of the surfactant in the PMEDM process. The preparation of nanofluid is done by mixing and sonicating thoroughly into the deionised water is discussed. The effect of varying the graphene nanopowder concentration into the dielectric is also discussed. Also, the effect of surfactant SDS and CTAB in the machining process is elaborated at 0.1 and 0.2g per 800ml concentration. MRR improved by 21.27% and roughness by 18.91% at 0.2g and 8µs, 2A and 50V in 800ml deionised water. SDS provide better MRR and low roughness compared to CTAB at higher peak current and higher pulse on time Simultaneously, the addition of surfactant into the dielectric medium reduces the performance of the EDM process. The MRR varies from 21mg/min at 0g graphene to 45mg/min at 0.2g and then 31.81mg/min at 0.2g with 0.1g SDS, 43mg/min at 0.2g SDS, 28.33mg/min at 0.1g CTAB and 30mg/min at 0.2g CTAB. Debris size also varies with the input parameters.

Abstract: Low temperature self-propagating forming coating material system for aluminum alloy cylinder parts was designed with Al, Fe₂O₃, Mo, Cu, Ni and Ti powders as raw materials. Low temperature self-propagating wear-resistant coating was prepared on the inner wall of aluminum alloy cylinder parts by thermal spraying ignition condensation centrifugal self-propagating fusion technology. XRD, DSC and SEM were used to study the microstructure, thermodynamic properties and cross-section morphology of the coating after thermal reaction of four kinds of low-temperature self-propagating materials with different proportions. The preparation process parameters of the coating were optimized by orthogonal test, including the amount of coating, the rotation speed of self-propagating centrifuge and the reaction time of self-propagating coating. The results show that the addition of Si, Mo and Zn powders in the four low temperature self-propagating powder systems can reduce the occurrence temperature of aluminothermic reaction; the optimal process parameters for coating preparation are rotational speed of 2000r/min, powder filling amount of 0.9g/cm³ and rotational reaction time of 16S.The results show that the coating with 20wt.% Al, 60wt.% Fe₂O₃, 12wt.% Si, 4wt.% Mo and 4wt.% Zn has better density and interface adhesion.

Abstract: A corrosion-resistant and wear-resistant coating was prepared on the inner wall of copper tube by centrifugal self-propagating melting. The surface morphology, composition and phase composition of the ceramic lining FGM coating were analyzed by XRD and SEM, and the synthesis mechanism of the ceramic coating was studied. The results show that the functionally gradient coating is composed of three layers: ceramic inner layer, metal transition layer and copper substrate layer. The surface of ceramic lining is smooth and dense, which is mainly composed of Al₂O₃, CaF₂ and a small amount of Fe Al spinel. The results show that the alumina phase is dendrite like and grows outward perpendicular to the tube wall, and the low melting point phase is evenly distributed in the dendrite gap, which effectively improves the density of the ceramic layer.

Abstract: Due to wear failures caused by tubing string vibrations in high-pressure, high-temperature and high-yield (3H) gas wells, a wear experiment was performed on the 13Cr-L80 tubing string. The influence of contact load, friction frequency, and reciprocating stroke length on the wear characteristics of the tubing string were effectively analyzed using the control variable method. The results demonstrate that, the wear patterns of the tubing-casing were primarily abrasive and adhesive wears, with minimal corrosion wear. The wear amount of tubing increases linearly with the increase of contact load and reciprocating stroke, but increases nonlinearly with the increase of friction frequency, and the friction coefficient of tubing string do not change with the increase of contact load, friction frequency and reciprocating stroke. In-field operations, the service life of the tubing string in 3H gas wells can be effectively augmented by reducing the contact load and longitudinal vibration displacement of the tubing-casing, maintaining the vibration frequency of the tubing string below 1.5 Hz. These results provide useful guidance for designing and implementing approaches to improve the service life of tubing strings in high-yield gas wells.

Abstract: In recent years, the oil field chemical A-cyanoacrylate mixed adhesive has been used in rock preparation and preparation to a certain extent, and its role has been paid more and more attention due to the solidification of the rock surface in the rock thin section, the early embedding of the rock, and the adhesion of the thin side of the rock to the slide surface, etc. This paper introduces the preparation and application development of a-cyanoacrylate mixed adhesive in geological experiment, and the development of a-cyanoacrylate mixed adhesive in oilfield geological experiment.

Abstract: The research of fluid inclusion thin section is to understand the physical and chemical conditions (such as temperature, pressure, density, pH value, composition, etc.) of minerals, rocks and deposits, and to solve the genesis of rocks and deposits; in the process of production, gas inclusions or liquid inclusions should be produced at low temperature, otherwise the inclusions will be destroyed, especially quartz sandstone, weathered rock, mudstone and other minerals Therefore, when the film is made in a humid temperature environment, it is very easy to be deliquesced, especially for the rocks with developed cleavage and many cracks, after rough grinding after polishing, it is easy to produce warping edge, warping angle, bubbles, etc., thus causing the sample piece to deteriorate after polishing; therefore, a large number of pockmarks and cracks will be produced under the microscope. In this paper, starting from the applicable conditions of materials and technological methods, the practical problems of making materials and technological process in rock slice method are introduced in detail. Keywords Inclusion,Manufacturing, Grinding,Polishing,Filming

Abstract: A white light, i.e., Fabry-Perot, interferometry was unprecedently applied to determine the rate change of the current density (J) of aluminum samples during the anodization processes of the samples in aqueous solutions. The current density(J) values were obtained by Fabry-Perot interferometry rather than the direct current (DC) or alternating current (AC), methods. Therefore, the abrupt rate change of the J was called electrochemical-emission spectroscopy. The anodization of the aluminum samples was conducted by an external DC source in 0.0,2,4,6,8,10% sulfuric acid (H₂SO₄) solutions at room temperature. In the meantime, the Fabry-Perot interferometry was used to determine the difference between the J of two subsequent values, dJ, as a function of the elapsed time of the DC experiment for the aluminum samples in 0.0,2,4,6,8,10% H₂SO₄ solutions. The Fabry-Perot interferometry was based on a fiber-optic sensor in order to make real time-white light interferometry possible at the aluminum surfaces in the sulfuric acid solutions. As a result, a new spectrometer was developed based on the combination of the Fabry-Perot, i.e., white light, interferometry and DC method for studying in situ the electrochemical behavior of metals in aqueous solutions.

Abstract: Surface-enhanced Raman scattering (SERS) has unique properties including highsensitivity, simple operation and non-destructiveness in trace detection; and the substrate will cast adirect impact upon the SERS signal. An everlasting topic has been focused on the preparation ofSERS substrates with controllable morphologies and hotspots. Herein, we reported a SERS substratewith alloyed Au-Ag nanospheres prepared via a reduction method of two-step seed growth method inliquid phase. TEM, SEM, Raman and UV-vis characterization have been employed to investigatemicro-morphology, composition, and SERS effects. Moreover, a quantitative detection model isestablished, and the R2 of fitting reaches as high as 0.982. Finally, the effect of different nAu/nAg molarratios on the SERS effect is investigated, with results showing that Raman enhancement has a goodrise at the very first beginning, but a drop later appears along with the decreasing nAu/nAg. The limit ofdetection (LOD) of R6G on Au-Ag nanosphere substrates has an initial increase, and a decreasefollows with the decreasing nAu/nAg ratios; the mechanism is also fully investigated. The preparationof particle-sized controllable Au-Ag nanomaterials helps provide a new highly enhanced SERSsubstrate.