High temperature oxidation resistance and microstructure change of aluminized coating on copper substrate

The outermost coating with single phase Ni2Al3 was obtained on copper surface by electrodepositing nickel followed by slurry pack aluminizing at 800 °C for 12 h. The oxidation resistance and microstructure of the coating oxidized in ambient air at 1000 °C for 25-250 h were investigated using SEM, X-ray diffraction and optical microscope methods. The results show that the copper with single phase Ni2Al3 coating possesses the best high temperature oxidation resistance, and the mass gain of the coating is 1/15 that of pure copper and 1/2 that of nickel coating, respectively. The specimen surface after being oxidized for 25 h still comprises Ni2Al3 phase. However, when the time of oxidizing treatment increases to 50 h, the Ni Al phase is formed. It is also found that the Ni2Al3 phase completely turns into Ni Al phase after oxidizing treatment for 100 h and above. The Ni Al coating shows excellent high temperature oxidation resistance when oxidation time is 250 h.

Microstructure and high temperature oxidation resistance of Si-Y co-deposition coatings prepared on TiAl alloy by pack cementation process

In order to improve the high temperature oxidation resistance of TiAl alloy, Y modified silicide coatings were prepared by pack cementation process at 1030, 1080 and 1130 °C, respectively, for 5 h. The microstructures, phase constitutions and oxidation behavior of these coatings were studied. The results show that the coating prepared by co-depositing Si?Y at 1080 °C for 5 h has a multiple layer structure: a superficial zone consisting of Al-rich (Ti,Nb)5Si4 and (Ti,Nb)5Si3, an out layer consisting of (Ti,Nb)Si2, a middle layer consisting of (Ti,Nb)5Si4 and (Ti,Nb)5Si3, and aγ-TiAl inner layer. Co-deposition temperature imposes strong influences on the coating structure. The coating prepared by Si?Y co-depositing at 1080 °C for 5 h shows relatively good oxidation resistance at 1000 °C in air, and the oxidation rate constant of the coating is about two orders of magnitude lower than that of the bare TiAl alloy.

Development of a High-Temperature Thixotropic Cement Slurry System

Cementing carbonate reservoirs is generally a difficult task.The so-called thixotropic cement slurry has gained considerable attention in this regard as it can help tofix some notable problems.More precisely,it can easilyfill the leakage layer;moreover,its gelling strength can grow rapidly when pumping stops,thereby increasing the resistance to gas channeling,effectively preventing this undesired phenomenon in many cases.High-temperature thixotropic cement slurry systems,however,are still in an early stage of development and additional research is needed to make them a viable option.In the present study,using a self-developed composite high-temperature thixotropic additive as a basis,it is shown that the compressive strength can be adjusted by tuning the proportion of silica sand,the high-temperature retarder,fluid loss additive and dispersant(compatible with the thixotropic additive).According to the tests,the developed high-temperature thixotropic cement slurry system has a 14 d compressive strength of 29.73 MPa at 150°C,and a thickening time of 330 min when the dosage of retarder is 2%.At the same time,the rheological property,water loss,permeability,water separation rate,and settlement stability of the cement slurry system meet the requirements of cementing construction.

Plugging property and displacement characters of a novel high-temperature resistant polymer nanoparticle

The goal of the research was to investigate the profile control and oil displacement characteristics of the polymer nanoparticles after high temperature swelling.The displacement parameters showed considerable influence on the plugging effect of the high-temperature swelled polymer nanoparticles,such as the core permeability,concentration of nanoparticles in the suspension,swelling time and swelling temperature,which makes it flexible to control the plugging effect by controlling displacement experiments conditions.Experimental results show that polymer nanoparticles dispersion system with a concentration of 500 mg/L is suitable for cores plugging with a permeability of 30×10^(-3)-150×10^(-3)μm^(2),even after aging at 150℃ for three months.The shunt flow experiments show that when the displacement factors are optimal values,the polymer nanoparticles after high temperature swelling to plug the high-permeability layer selectivity and almost do not clog the low-permeability layer.Oil recovery of homogeneous artificial core displacement experiment and a heterogeneous double-tube cores model are increased by 20%and 10.4%on the basis of water flooding.The polymer nanoparticles can be a great help for petroleum engineers to better apply this deep profile control and flooding technology.

Screening of High Temperature Resistant Fodder Yeast Strains

[ Objective] This study aimed to screen yeast strains suitable for high temperature processing of formulated biological feed. [ Method ] High temperature resistance and culture conditions of six yeast strains were investigated. [Result] Two yeast strains resistant to high temperature （45 ℃ ） with high viable cell number （10^8 cells/ml） were screened, including DQFC2117-1 and DQFC2122-2. [ Conclusion] Strains DQFC2117-1 and DQFC2122-2 could be used as high temperature resistant yeast strains for processing of formulated biological feed.

Laboratory Study on 210°C High Temperature and Salt Resistant Drilling Fluid

Combined with the current research status in this area at home and abroad, with the improvement of salt and high temperature resistance as the research goal, the laboratory research of salt and high temperature resistant drilling fluid system has been carried out, and lubricants, inhibitors and stabilizers have been optimized. The final drilling fluid formula is: water + 3% sepiolite + 0.3% Na2CO3 + 3% RH-225 + 3% KCOOH + 3% G-SPH + 3% CQA-10 + 1.5% ZX-1 + Xinjiang barite, density 2.2 g/cm3, using hot-rolling furnace, environmental scanning electron microscope, high temperature and high pressure plugging instrument and Zeiss microscopes and other instruments use core immersion experiments, permeability recovery value experiments, and static stratification index methods to perform temperature resistance, reservoir protection, plugging performance, and static settlement stability performance of the configured drilling fluid., Inhibition performance, biological toxicity, salt resistance, anti-pollution performance have been tested, and it is concluded that the temperature resistance is good under the condition of 210°C, and the salt resistance can meet the requirements of 20% NaCl + 0.5% CaCl2 concentration. It has a good reservoir protection effect, the permeability recovery value can reach more than 90%, the performance of restraining water dispersion and cuttings expansion is good, the heat roll recovery rate can reach more than 85%, and the SSSI value shows that its settlement stability performance is good;Its plugging performance is good under high temperature and high pressure. It laid the foundation for the next step to promote the field application of the drilling fluid system.

Research progress of high temperature resistant nylon 10T

Researches about synthesis and modification of nylon 10T(PA10T)in domestic universities and scientific research institutions are reviewed in this paper.The results show that,due to the different performance requirements,PA10T is studied from the co-polymerization,blending modification and filling modification of these three aspects.Meanwhile,the existing problems are analyzed and the development prospect of PA10T is predicted.

Research progress and development of deep and ultra-deep drilling fluid technology

The research progress of deep and ultra-deep drilling fluid technology systematically reviewed,the key problems existing are analyzed,and the future development direction is proposed.In view of the high temperature,high pressure and high stress,fracture development,wellbore instability,drilling fluid lost circulation and other problems faced in the process of deep and ultra-deep complex oil and gas drilling,scholars have developed deep and ultra-deep high-temperature and high-salt resistant water-based drilling fluid technology,high-temperature resistant oil-based/synthetic drilling fluid technology,drilling fluid technology for reservoir protection and drilling fluid lost circulation control technology.However,there are still some key problems such as insufficient resistance to high temperature,high pressure and high stress,wellbore instability and serious lost circulation.Therefore,the development direction of deep and ultra-deep drilling fluid technology in the future is proposed:(1)The technology of high-temperature and high-salt resistant water-based drilling fluid should focus on improving high temperature stability,improving rheological properties,strengthening filtration control and improving compatibility with formation.(2)The technology of oil-based/synthetic drilling fluid resistant to high temperature should further study in the aspects of easily degradable environmental protection additives with low toxicity such as high temperature stabilizer,rheological regulator and related supporting technologies.(3)The drilling fluid technology for reservoir protection should be devoted to the development of new high-performance additives and materials,and further improve the real-time monitoring technology by introducing advanced sensor networks and artificial intelligence algorithms.(4)The lost circulation control of drilling fluid should pay more attention to the integration and application of intelligent technology,the research and application of high-performance plugging materials,the exploration of diversified plugging techniques and methods,and the improvement of environmental protection and production safety awareness.

Microstructure and corrosion resistance of sputtered TiN coatings on surface of Zr-4 alloy

To improve the oxidation resistance and corrosion resistance of Zr-4 alloy, titanium nitride （TIN） coatings were prepared on the Zr-4 alloy with a TiN ceramic target with different ratios of N2. Microstructure and high-temperature properties of the TiN coated samples were studied by scanning electron microscopy （SEM）, energy dispersive spectrometer （EDS）, X-ray diffraction meter （XRD）, X-ray photoelectron spectroscopy （XPS）, heat treatment furnace and autoclaves, respectively. The x value of the TiN coatings （TiN） ranges from 0.96 to 1.33. After the introduction of N2, TiN coating exhibits a weak （200） plane and a preferred （111） orientation. The coating prepared with an N2 flow ratio of 15% shows an optimal oxidation resistance in the atmospheric environment at 800 ℃. In either 1 200 ℃ steam environment for one hour, or deionized water at 360 ℃ and a pressure of 18.6 Mpa for 16 d, the opitimized TiN coated samples have no delamination or spallation; and the gains in the masses of samples are much smaller than Zr-4 alloy. These results demonstrate the effectiveness of the optimized TiN coating as the protective coating on the Zr-4 alloy under extreme conditons.

Structures and Properties of High-Carbon High Speed Steel by RE-Mg-Ti Compound Modification

The effects of rare earths(RE)-Mg-Ti compound modification on the structures and properties of high-carbon high speed steel(HSS) were researched.The impact toughness(α_k),the fracture toughness(K_(1c))and threshold of fatigue crack growth(ΔK_(th))are tested.The thermal fatigue test is done on a self-straining thermal fatigue tester,the wear test is done on a high temperature wear test machine.The results show that the matrix can be refined by the RE-Mg-Ti compound modification,the eutectic carbides are inclined to spheroidicize and are distributed evenly,the morphology and distribution of eutectic carbides are improved by appropriate RE-Mg-Ti complex modification.After RE-Mg-Ti compound modification,a little effects can be found on the strength,hardness and red hardness,but the fracture toughness(K_(1c)) and threshold of fatigue crack growth(△K_(th)) are improved in the meantime,the impact toughness (α_k) is increased by over one time,and the resistance to thermal fatigue and wear resistance at an elevated temperature are remarkably improved.

Design of TE_(01δ) Test Probe for Measuring the Microwave Surface Resistance of HTS Thin Film

A new TEo1δ test probe with proper transmission factor is fabricated for the measurement of surface resistance of high temperature superconductor （HTS） thin film. Coupling holes instead of coupling loops are used in the probe for its easier machining and relatively low loss. Two 6 mm × 3 mm × 8 mm dielectric waveguides, one side of them is coated by silver, are used for coupling. The measurement result of S21 agrees well with the simulation because the size of the probe can be rigidly controlled by machine. The microwave surface resistance of four YBCO/MgO films are measured at 77 K and 12 GHz and scaled to 10 GHz according to thef2 rule. The average surface resistance of four HTS thin fdms is 0.38 mΩ, the standard deviation and relative standard deviation of one single HTS thin film are 0.009 mΩ and 2.4%, respectively.

Study and Application of a New Association Polymer System for Profile Control

A new polymer system, referred to simply as the AP-P4 polymer system, aims at solving the problems of high temperature, high salinity and the poor shearing resistance, all of which are encountered by conventional polymers (such as polyacrylamide) used in profile control, profile performance improvement and EOR operations in the Zhongyuan Oilfield, Sinopec. This system has been developed on the basis of the specific molecular structure and the better properties of high temperature resistance, high salinity resistance and strong shearing resistance of the new type of AP-P4 association polymer. Acidity modifying agents and cross-linking agents (MZ-YL, MZ-BE, MZ-XS), compatible with the new polymer system, are selected. Results of performance tests have shown that the new polymer system has excellent thickening, high temperature, high salinity and shearing resistance and anti-dehydrating properties. In 2003, it underwent its first pilot test in 26 wells in China, with remarkable effects in increasing oil production and decreasing water production. The newly developed polymer system and its application technology described in this paper may play a guiding role in polymer profile control operations in the oil reservoirs of high temperature and high salinity.

Excellent electromagnetic wave absorption of MOF/SiBCN nanomaterials at high temperature

Electromagnetic wave absorbing materials at high-temperature are urgently needed for stealth aircrafts or aero-engines worked in harsh environments.In this contribution,cobaltcontaining siliconboron carbonitride(MOF/SiBCN)nanomaterials were prepared by pyrolyzing metal–organic framework,i.e.cobalt 2-methylimidazole(ZIF-67),and hyperbranched polyborosilazane.The rhombic dodecahedral ZIF-67 and cobalt element promoted in situ formation of dielectric loss phases,including SiC nanocrystals,CoSi nanocrystals and turbostratic carbons.The ZIF-67/SiBCN nanomaterials showed excellent microwave absorption both at room and elevated temperature.The minimum reflection coefficient(RC_(min))was-51.6dB and effective absorption bandwidth(EAB)is 3.93GHz at room temperature.At an elevated temperature of 600℃,the RC_(min) reached-30.29 dB and EAB covered almost the whole X-band(3.95GHz,8.45–12.4GHz).The ZIF-67/SiBCN nanocomposites are promising and useful platform for microwave absorbing materials at high-temperature.It may shed light on the downstream applications in designing next generation areo-engines and stealth aircrafts.

3D-printed controllable gradient pore superwetting structures for high temperature efficient oil-water separation

Superwetting surfaces have the potential to address oil pollution in water,through their ability to separate the two.However,it remains a great challenge to fabricate stable and efficient separation structures using conventional manufacturing techniques.Furthermore,the materials traditionally used for oil-water separation are not stable at high temperature.Therefore,there is a need to develop stable,customizable structures to improve the performance of oil-water separation devices.In recent years,3D printing technology has developed rapidly,and breakthroughs have been made in the fabrication of complicated ceramic structures using this technology.Here,a ceramic material with a gradient pore structure and superhydrophobic/superoleophilic properties was prepared using 3D printing for high-efficiency oil-water separation.The gradient pore structure developed here can support a flux of up to 25434 L/m^(2)h,which is nearly 40%higher than that an analogous structure with straight pores.At 200℃,the oil-water separation performance was maintained at 97.4%.Furthermore,samples of the material exhibited outstanding mechanical properties,and chemical stability in a variety of harsh environments.This study provides an efficient,simple,and reliable method for manufacturing oil-water separation materials using 3D printing,and may have broader implications for both fundamental research and industrial applications.

Zirconia Hollow Spheres and Their Application

Zirconia hollow sphere products are ultra-high temperature energy saving lightweight insulating refractories in zirconia system.They not only have the same refractoriness as zirconia products,but also have the advantages of low bulk density and excellent thermal insulation properties.Their thermal conductivity is 0.3-0.4 W · m-1 · K-1 only 1/2 of that of the ordinary zirconia products.They are special refractories which can be used steadily up to 2 400 ℃ in oxidation,reduction and vacuum atmospheres.Zirconia hollow sphere products are the best lining refractories for various ultra-high temperature kilns and furnaces of tungsten and molybdenum metal products processing,artificial crystals,and quartz industrial production.

Study on a Polyamine-Based Anti-Collapse Drilling Fluid System

In complex strata, oil-based drilling fluid is the preferred drilling fluid system, but its preparation cost is high, and there are hidden safety risks. Therefore, the new progress of high-performance anti-collapse water-based drilling fluid at home and abroad is analyzed. It is difficult to prevent and control the well collapse. Once the well wall instability problem occurs, it will often bring huge economic losses to the enterprises, and the underground safety accidents will occur. In order to ensure the stability of the well wall and improve the downhole safety, the key treatment agent of water-based collapse drilling fluid is selected, the anti-collapse drilling fluid system is formulated, the evaluation method of drilling fluid prevention performance is established, and a set of water-based drilling fluid system suitable for easy to collapse strata in China is selected to ensure the downhole safety. The development trend of high performance anti-collapse water-based drilling fluid is expected to provide a reference for the research of high performance anti-collapse water-based drilling fluid system and key treatment agent.

Development and application of a new hot-work die steel for hot stamping

A new hot-work die steel for hot stamping was developed, and used the die for mass production. The produced die showed good performance owing to its high heat conductivity and wear-resistant characteristics. Two different benchmarking hot-work die steels were investigated, and then compared in terms of their impact ductility, temper characteristics ,heat conductivity, and thermal stability. The result of the high-temperature friction wear test indicated that oxidative wear was the main mode in high temperature. On the basis of the comparison and test results, the alloying composition of the new hot-work die steel was especially designed. The new die steel showed good performance with good wear-resistant quality, as well as temper hardness and heat conductivity of HRC 50 and 34.3 W/（ m ~ K）, respectively. Furthermore, without surface plasma nitriding, the die made of the new steel had no obvious galling with 6 142 strokes. After surface plasma nitriding, the die completed 40 000 strokes with good surface. The die life is expected to exceed 200 000 strokes.

High Temperature Deformation Behavior of Fe-9Ni-C Alloy

The high temperature deformation behavior of the 9Ni steel has been studied by the Gleeble-3500 tester. The relationship between deformation resistance and deformation degree, deformation temperature and deformation rate was revealed. The results show that when the deformation degree is less than 0.2, the deformation resistance increases by about 70 to 200 MPa, while the deformation degree varied between 0.2 and 0.4, the deformation resist- ance increases by about 30--40 MPa, when the deformation degree is larger than 0.4, the deformation resistance in- creases slowly, some become stable gradually. The influence of deformation temperature on deformation resistance is larger, and deformation resistance at higher temperature is about 160 MPa smaller than at lower temperature. Higher deformation rate leads to larger deformation resistance. The deformation resistance increases about 70 to 110 MPa with the increase of the deformation rate. A new and highly accurate mathematical model of the steel was established to describe the deformation behavior during rolling.

Resistivity response to the porosity and permeability of low rank coal

Laojunmiao coal samples from the eastern Junggar basin were studied to understand the relationship between coal resistivity and the physical parameters of coal reservoirs under high temperatures and pressures.Specifically,we analysed the relationship of coal resistivity to porosity and permeability via heating and pressurization experiments.The results indicated that coal resistivity decreases exponentially with increasing pressure.Increasing the temperature decreases the resistivity.The sensitivity of coal resistivity to the confining pressure is worse when the temperature is higher.The resistivity of dry coal samples was linearly related to φ~m.Increasing the temperature decreased the cementation exponent(m).Increasing the confining pressure exponentially decreases the porosity.Decreasing the pressure increases the resistivity and porosity for a constant temperature.Increasing the temperature yields a quadratic relationship between the resistivity and permeability for a constant confining pressure.Based on the Archie formula,we obtained the coupling relationship between coal resistivity and permeability for Laojunmiao coal samples at different temperatures and confining pressures.

Hyperelastic Graphene Aerogels Reinforced by In‑suit Welding Polyimide Nano Fiber with Leaf Skeleton Structure and Adjustable Thermal Conductivity for Morphology and Temperature Sensing

Graphene-aerogel-based flexible sensors have heat tolerances and electric-resistance sensitivities superior to those of polymer-based sensors.However,graphene sheets are prone to slips under repeated compression due to inadequate chemical con-nections.In addition,the heat-transfer performance of existing compression strain sensors under stress is unclear and lacks research,making it difficult to perform real-temperature detections.To address these issues,a hyperelastic polyimide fiber/graphene aerogel(PINF/GA)with a three-dimensional interconnected structure was fabricated by simple one-pot compound-ing and in-situ welding methods.The welding of fiber lap joints promotes in-suit formation of three-dimensional crosslinked networks of polyimide fibers,which can effectively avoid slidings between fibers to form reinforced ribs,preventing graphene from damage during compression.In particular,the inner core of the fiber maintains its macromolecular chain structure and toughness during welding.Thus,PINF/GA has good structural stabilities under a large strain compression(99%).Moreover,the thermal and electrical conductivities of PINF/GA could not only change with various stresses and strains but also keep the change steady at specific stresses and strains,with its thermal-conductivity change ratio reaching up to 9.8.Hyperelastic PINF/GA,with dynamically stable thermal and electrical conductivity,as well as high heat tolerance,shows broad applica-tion prospects as sensors in detecting the shapes and temperatures of unknown objects in extreme environments.