Engineering and Technology Journal

In this work, We prepared a modified nanostructure porous silicon (PS) layers for effective chemical gas sensing. Nanopore covered microporous silicon gas sensor has been fabricated using electrochemical etching in an HF acid and ethanol solution. A porous silicon (PS) surface has been modified using selective depositions formed from metal to enhance the response to Sensing of CO2. (PS) has been interest for gas sensing because of the exceptional gathering of importent features. By setting the process parameters,the porosity, pore size, and the morphology can be modifid and practically controlled. The modified porous silicon layers were characterized using different techniques such as scanning electron microscopy(SEM)and a series of electrical characterizations to study the structures in the contact of the carbon dioxide was achieved

Stainless steel has excellent corrosion resistance due to formation oxides protective films in many environments. When steel exposed to temperature in the range of (500-900) ºC, the carbon in the structure will be effective to react with chromium in the structure , which is no less than 18.6% in the present used steel, to form chromium carbides in different types (M23C6, M7C3, M2.9C) in which M represent chromium. Therefore pitting corrosion will be initiated due to two reasi, the first was depleted zone and the second is galvanic effects between carbides and matrix. The present work was aimed to find relationships to predict the initiation of pitting corrosion depending on carbides in the microstructure of 304 stainless steel, which formed in heated specimens at (500 - 900) ºC. The potentiodynamic cyclic polarization (PCP) measurement was performed to investigate and analyze pitting corrosion resistance properties.

Indium oxide and indium tin oxide composite (ITO) were prepared by sol-gel dip-coating (SGDC) technique. The particles annealed at (200 ◦C, 400 ◦C). The structure and surface morphology of particles were characterized by X-ray diffraction (XRD), Atomic Force Microscope (AFM), FT-IR and UV/visible measurements. The XRD and AFM indicate decreasing in the particle size and improve of optical and electrical properties of composite with increasing of tin oxide addition. The hall measurement were used to obtain information about the type of conductivity of indium oxide and indium tin oxide thin films and carrier concentration and mobility and resistivity, the results of Hall measurements show that the In2O3 and ITO composite have n-type. The thin film of composite ITO at composition (80:20) mole ratio has high sensitivity toward CO gas compared with pure indium oxide.

Poly amide (PA-6) nanofiber coatings on aluminum surface using electrospinning technique under two different voltage (24 kV & 34 Kv) were prepared. The coating morphology , roughness and 3D structural properties tested by using Atomic force microscopes (AFM), surface characterized by (SEM) microscopy, and high resolution optical microscopy (HROM) , Contact angle for hydrophobic behavior was tested by shape drop analyzer , and FTIR analysis for changing in crystalline structure was performed .The AFM images showed that the PA coating on the aluminum surface have a tight and twisted nanofiber structure with some beads through its morphology. SEM images shows the morphology beads of surface nanofibers . The electrochemical corrosion of aluminum without and with PA coating studied by subjected it to aerobic solutions of 3.5 wt.% sodium chloride (NaCl) . It has been found that the PA coatings decrease the corrosion currents and corrosion rate as well as increase the corrosion resistance for aluminum in the NaCl solution

Refractory mixtures were prepared from: bauxite raw materials, grog and Kaolin. Different weight percentage of micro-SiC (5, 10, 15 and 20 wt%) and nano-SiC (2.5,5,7.5 and 10 wt%) was added to bauxite mixture to improve the refractories characteristics to suit the lining of oil treatment units. Semi-dry pressing used to forming cylindrical specimens with load (7 ton) and 25 mm in diameter after mixing the powder with 10 wt% Sodium Silicate as a binder. The specimens dried at (110 oC) for (2 h) and fired at (1400 oC) with soaking time (2 h). During firing process, some of nano-SiC powder oxidants and transformed to SiO2 glass phase with increasing mullite phase. Therefore; the bonds with bauxite increases as a result glass phase generated and lead to decreasing the porosity and increasing the shrinkage, density and mechanical properties compared with micro-SiC additives

Partial Stabilized Zirconia (PSZ) was prepared from adding 3 wt % of MgO or adding 8 wt% of Y2O3 to 90 wt % ZrO2 Powder and mixed by wet method, then dried and firing mixture to 1500C to obtain PSZ ceramic powder. Glass-Ceramic (Li2SiO3) and (LiAlO2) prepared by dissolve lithium carbonate and lithium hydroxide with Nano-Silica (SiO2) and Nano-Alumina (Al2O3) respectively. Those glass-ceramic mixed with PSZ in different percentage (2.5,5,7.5,10) and sprayed on furnaces bricks for petroleum refineries. An increase in the chemical resistance of the acid on the surface of the Refractory bricks was observed when coating with the glass-ceramic mixture, as well as increasing the hardness and thermal shock resistance. Lithium silicate coated specimens are more spared and homogeneous on the surface compared to lithium laminate coated.

In this research a nano polymeric coating has been prepared to be used for the protection of the external surface of oil pipelines (medium carbon steel (CK50)) from corrosion in salt water (3.6% NaCl) . This coating is reinforced by inorganic (nano and micro) additives to apply a high resistance against chemicals and salts. These oxides protect the epoxy resin from degradation by preventing the epoxy molecules and active functional groups from absorbing ultraviolet light in the range (290-315) nm strongly.This coating is also resistant to the high and low temperatures, humidity, scratch and water. This coating was prepared from the reaction of 2-[[4-[2-[4-(Oxiran-2-ylmethoxy) phenyl] propan-2-yl] phenoxy] methyl] oxirane (Diglycidyl Ether of Bisphenol A) and the hardener (EDA). The mixing ratio of the two parts was (4:1). Reinforced with inorganic (nano and micro) additives such as titanium dioxide (TiO2) and zinc oxide (ZnO) which have been used as an anticorrosion. These additives are non-toxic, thermally stable and have a high degree of the miscibility with epoxy. The weight percentages of the mixing are (0 and 10 % wt). The corrosion rate results show that using (nano and micro) coating give good results in increasing the corrosion resistance compared with the (non additives) epoxy.This coating was characterized using different spectroscopic methods (FT-IR, UV/Vis). Several tests were conducted ,
including differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) , mechanical tests and evaluation of corrosion resistance was made by using static potential test.

Advanced utility, diesel and turbines engines used widely in aerospace, chemical and oil industries are based on plasma sprayed thermal barrier coatings. The successful performance of these coatings during servicing are relied mostly on the careful design, selection and analysis of zirconia-based ceramic powders stabilized with yttria and ceria. Different design of sampling techniques relevant for each evaluates property is a key factor to obtain reliable data. Significant property differences were observed for single and mixed powders. In the present work the particle size, its distribution, apparent density, flow rate, biased standard deviation, unbiased standard deviation and phases were characterized using sieving, flowmeter, scanning electron microscopy (SEM), X-ray diffraction (XRD), step scanning X-ray diffraction, energy dispersive spectroscopy (EDS), electron microprobe analysis (EPMA) and FT-IR. Two single alloyed zirconia powders of zirconia- 25 wt% CeO2-2.5 wt% Y2O3 (Sulzer Metco 205NS) and zirconia- 8 wt% Y2O3 (Sulzer Metco 204NS-G) and mixture of these powders 80 wt% (Sulzer Metco 205NS) and 20 wt% (Sulzer Metco 204NS-G) were investigated. The particle shape has a remarkable effect on the flow rate and apparent density rather than the other properties. The particle distribution gives important noticeable information for the plasma spraying coatings

Thoroughly qualitative and quantitative topography, microstructure, splats formation and phases evaluation were made to understand carefully the behavior of plasma sprayed zirconia-ceria-yttria coatings processed under near optimum processing conditions. The study is focused on how to design and select the given property to predict the reliable data of plasma sprayed zirconia-20 wt% CeO2-3.6 wt% Y2O3. The processing and plasma spraying parameters were designed carefully to give a reliable clear evaluation of the microstructure. The results showed a heterogeneous microstructure in which melted, semimelted and unmelted particles were existed. The phases formed are consisted of nontranformable tetragonal phase (t') with small amount (less than 2 mole%) of monoclinic phase (m). The electron probe microanalysis (EPMA) suggests the intimate mixing between the binary systems of zirconia-ceria and zirconia-yttria during spraying. The Image J technique, SEM, EPMA, EDS and XRD/step scan XRD were used collectively to build up a clear picture on the solidification mechanism of the new plasma sprayed coating system.

Nanotechnology is one of the most important techniques in recent days. Using Nano-additives to improve drilling fluids properties in order to meet the modern drilling process requirement is still being debated till date. In this study, three Nano-materials (magnesium oxide MgO, titanium dioxide TiO2 and Graphene) were used to improve the rheological and filtration properties as well as Clay Yield. The weight of Nano-materials were (0.02, 0.05, 0.2, 0.5, 0.8) gm. The results showed that the rheological properties were the same with Graphene and TiO2, while MgO gave the best results of rheological and filtration properties and with a higher values of yield point and gel strength. The higher value of Clay Yield obtained by0.2wt % (0.8 gm) of MgO was (173bbl/ton) while TiO2 and Graphene gave the same values (124,126 bbl/ton) respectively.

In the present investigation, titania (TiO2) nano-thin films were deposited on steel type A106-B, by using the Pulse Laser Deposition (PLD) technique to obtain passive layers of nano-coating. Electrochemical methods (Tafel completion) are used for study corrosion behavior of steel coating. The A106-B specimens were evaluated in 3.5 wt. % NaCl aqueous solution by using polarization technique with pH adjustment to 4.0 in order to determine the corrosion rate. The samples of TiO2 thin films were characterized by SEM, AFM, XRD, and FTIR. The input parameters were substrate temperature (100, 200 and 300) ’0C’, number of pulse (300, 400 and 500) and fluencies energy (800, 900 and 1000) mJ/cm2, have been investigated to detect their impact on corrosion reduction rate using Taguchi methodology orthogonal array and Analysis of Variance (ANOVA).The ANOVA results indicates that number of shoots pulse significantly affecting the corrosion rate in PLD technique, which is highest among the contributions of the other parameters which is (58.03%) about three times of the fluencies energy (19.12%).The results show that the TiO2 deposition on steels offers an excellent corrosion resistance about 99 times as compared with uncoated steel. The optimum conditions to minimum values corrosion rate are: temperature of 300ºC, number of laser pulses at 300, and fluencies energy equal to 1000 mJ/cm2. Finally the optimal parameters that was used to predict the conclusions were (98.6) to the response of corrosion rate.

The present paper investigates numerically the enhancement of heat transfer with CuO nanofluid flowing in a horizontal circular tube fitted with different shapes of twisted tape. Finite volume method with ANSYS FLUENT in three dimensions is used in numerical investigation. The effect of twist ratio, concentration of nanofluid, twisted tape type with single phase flow on values of Nusselt number and friction factor are investigated. Heat transfer is enhanced as Reynolds number increases and twist ratio decreases.