Cement has been used for decades in the industry to serve various important functions inside oil and gas wells. Due to the complications and variations in the geological and technical conditions of a well, various cement compositions are designed and utilized in different world regions. Many hydrocarbon reservoirs are covered by thick salt formations, which are considered problematic and costly to be drilled and cemented. Cement slurry, as a water based solution, interacts with salt rock, as a result of which cement properties are changed that consequently may jeopardize well integrity across salt formations and successful exploitation of beneath hydrocarbon reservoirs. In this study, based on experimental and industrial experiences, a cement composition is developed that meet the requirements of cementation in salt layers. Experimental investigations are conducted on the bonding strength at the salt-cement interface, as the bonding strength is considered as one of the factors that significantly affect overall cement efficiency in providing well integrity. Results confirm the effectiveness of the developed composition for cementation of salt layers.

In this research, the diffusion bonding of the stabilized zirconia ceramic and Nimonic 105 superalloy using Ti/Nb/Ni multi-interlayer was carried out. Joint was performed using the plasma spark technique in a vacuum atmosphere and at different temperatures and times. The microstructure of the different joint zones was studied using optical and FESEM microscopes equipped with an EDS analyzer. The results showed that the critical region is Ti/3YSZ interface and in all conditions diffusion bonding in Ti/Nb, Nb/Ni, and Ni/NI 105 interfaces were done. Microstructural observations showed that in the Ti/3YSZ interface at all temperature and time conditions, the connection of two separate regions including Ti3O and (Zr, Ti)2O was formed due to the difference in the diffusion depth of Ti, Zr, and O elements and with increasing temperature and time, the thickness of these regions increased. Microstructural studies showed that the bond at 900 ℃ and 30 minutes did not have any cracks and discontinuities and due to the better diffusion of atoms, a suitable reaction layer was formed. Microhardness observations and EDS analyses confirmed that the Ti3O reaction layer is the weakest zine.

Background and Aims: Poor adhesion between porcelain and some of the dental alloys is one of the most challenges to select the desirable alloy in dental restorations. Therefore, the aim of this study was to evaluate the bond strength of porcelain to some of the commercial alloys. This can help in selection of desirable alloy. Materials and Methods: The shear bond strength of porcelain to the three of the most widely used nickel-base dental alloys commercially named as: Verabond, Damcast and Noritake were evaluated according to standard ASTM E4. The results were analyzed based on the statistical method of independent t with the meaningful level of P<0. 05. Then, the bonding interface of the fired samples was evaluated using SEM equipped with EDX analyzer and X-ray diffractometry. Results: The average bonding strength of porcelain to each of the above mentioned alloys were determined as: 27. 54± 5. 48, 22. 46± 4. 99 and 26. 18± 4. 27 MPa, respectively. Due to the existence of Be and Al in the chemical composition of Verabond and Damcast and their higher appetencies to form the different surface oxides in preference to Cr2O3, not only the bond strength of porcelain to two these alloys was increased about 20 percent (compared with the Noritake), but also the color of their porcelain was not changed. Conclusion: To replace the replacing of deleterious elements from the chemical composition of dental alloys. The added new elements should control through the oxide layer and the formation of Cr2O3 in porcelain-alloy interfaces for adequate bond strength.

Hypothesis: Fatigue crack growth (FCG) of rubber composites as controlled by the viscoelastic losses, is strongly dependent on the polymer-filler interfacial phenomena. The type of filler-polymer bonding at the interface and the extent of mobility restriction of rubber chains resulting from the interaction by the filler are of the critical ones. In highly filled rubber compound, the amount of mobility restriction is almost dictated by the filler-filler interaction. Regulating the surface energy of the filler can be an effective method to control the filler-filler interaction, to distinguish the two interfacial phenomena, and to pave the way of studying their significance. Methods: Ultrasil VN3 and solution styrene-butadiene rubber (SSBR) were of the base composite materials. Using two silanes with a short and a long aliphatic chain length, the surface of Ultrasil was modified in our lab to a certain level of grafting density which could bring the required surface energy and the filler-filler interaction. By controlling the surface energy of silica treated in the lab, and by making a systematic comparison of the resulting composites, it was possible to study the role of covalent bonding at the interface, the role of filler-filler interaction and severity of mobility restriction and finally the role of silane chain length. Findings: Fatigue crack growth experiment revealed that the severity of mobility restriction and the filler-filler interaction of the composite have the highest impact on the amount of viscoelastic dissipation and the rate of crack growth. The covalent bonding at the interface can deviate the crack from growing in the original direction and thus it may act as a physical barrier to improve crack growth resistance. For highly filled compounds where the properties are almost dictated by the filler-filler interaction, the role played by the chain length of silane is minor.

Compound casting is a specialized manufacturing process used to create ‎components or structures composed of two separate metals. In this research, ‎bimetallic compounds consisting of AISI 321 and Co. were produced by ‎the compound casting method. This process involves pouring molten metal onto a ‎steel core. During the casting process, the molten company surrounds the core ‎and can solidify due to the dynamic interaction between the liquid and the steel. ‎This agent and passivity create a unique relationship between two substances ‎and as a result, intermetallic compounds are created. In this research, two key ‎factors with the volume of the molten metal to the volume of the solid ‎core have been investigated. These changes were analyzed using electron ‎microscopy (SEM) with elemental point analysis (EDS). The results show that ‎increasing the ratio of the volume of the melt to the solid is related to the ‎increase of the thickness of the joint and the steel. When the ratio of melt to ‎solid volume increased, the solidification time also increased. This increase in ‎freezing time has an effect on the amount of steel penetration in the solid metal ‎being frozen. The results of EDS analysis showed that the bimetallic master ‎chapter consists of different intermetallic compounds, which include FeAl3, ‎Fe2Al5, FeAl2, and FeAl. These compounds are formed due to the chemical ‎reactions between steel and steel at the interface, and their presence is important ‎in understanding the properties and behavior of the composite structure.‎

Multilayered ceramic-metal composites were produced by solid state diffusion bonding of polycrystalline alumina and three Al alloys containing 1 to 2%Sr, 2% Mg and Mg + Si (5057 Al alloy). The multilayered structures were fabricated at 610°C under a compressive stress of 3 MPa for 2 hours in He-5%H atmosphere. The ceramic-metal interfaces were studied by SEM and TEM equipped with an energy dispersive spectrometer (EDS). Addition of 1 wt % Sr to Al promoted good adhesion, without producing any interfacial products, while the Al-2wt%Sr was poor in this regard due to the presence of dispersed Al4Sr, which is an intrinsic phase in the Al-Sr phase system. The Al-2%Mg alloy produced a continuous film at the interface, which was characterized as being MgAl2O4. Al alloys containing Mg and Si (5057 commercial alloy) produced not only the spinel structure (MgAl2O4), but another phase rich in Mg and Si (close to Mg2Si). These latter interfacial reaction products were not the intrinsic phases in Al-Mg alloys, but were reaction products at the Al2O3 –Al alloy interfaces.