Effect of Interfacial Structure on Mechanical Properties of Graphene Reinforced Al2O3–WC Matrix Ceramic Composite

The interfacial structures and interfacial bonding characteristics between graphene and matrix in graphene-reinforced Al2O3–WC matrix ceramic composite prepared by two-step hot pressing sintering were systematically investigated. Three interfacial structures including graphene–Al2O3, graphene–Al2OC and graphene-WC were determined in the Al2O3–WC–TiC–graphene composite by TEM. The interfacial adhesion energy and interfacial shear strength were calculated by first principles, and it has been found that the interfacial adhesion energy and interfacial shear strength of the graphene–Al2OC interface (0.287 eV/nm2, 59.32 MPa) were far lower than those of graphene–Al2O3 (0.967 eV/nm2, 395.77 MPa) and graphene–WC (0.781 eV/nm2, 229.84 MPa) interfaces. Thus, the composite with the strong and weak hybrid interfaces was successfully obtained, which was further confirmed by the microstructural analysis. This interfacial structure could induce strengthening mechanisms such as load transfer, grain refinement, etc., and toughening mechanisms such as crack bridging, graphene pull-out, etc., which effectively improved mechanical properties.

Effects of Transition Element Additions on the Interfacial Interaction and Electronic Structure of Al(111)/6H-SiC(0001) Interface: A First-Principles Study

In this work, the effects of 20 transition element additions on the interfacial adhesion energy and electronic structure of Al(111)/6H-SiC(0001) interfaces have been studied by the first-principles method. For pristine Al(111)/6H-SiC(0001) interfaces, both Si-terminated and C-terminated interfaces have covalent bond characteristics. The C-terminated interface has higher binding energy, which is mainly due to the stronger covalent bond formed by the larger charge transfer between C and Al. The results show that the introduction of many transition elements, such as 3d transitional group Mn, Fe, Co, Ni, Cu, Zn and 4d transitional group Tc, Ru, Rh, Pd, Ag, can improve the interfacial adhesion energy of the Si-terminated Al(111)/6H-SiC(0001) interface. However, for the C-terminated Al(111)/6H-SiC(0001) interface, only the addition of Co element can improve the interfacial adhesion energy. Bader charge analysis shows that the increase of interfacial binding energy is mainly attributed to more charge transfer.

Effects of Transition Element Additions on the Mechanical and Electronic Structure Properties of Al (111)/6H-SiC (0001) Interface: A First Principles Study

In this work, effects of 20 transition element additives on the interfacial adhesion energy and electronic structure of Al (111)/6H-SiC (0001) interfaces have been studied by first principles method. For clean Al (111)/6H–SiC (0001) interfaces, both Si-terminated and C-terminated interfaces have covalent bond characteristics. The C-terminated interface has stronger binding energy, which is mainly due to the stronger covalent bond formed by the larger charge transfer between C and Al. The results show that the introduction of many transition elements, such as 3d transitional group Mn, Fe, Co, Ni, Cu, Zn and 4d transitional group Tc, Ru, Rh, Pd, Ag, can improve the interfacial adhesion energy of the Si-terminated Al (111)/6H-SiC (0001) interface. However, for the C-terminated Al (111)/6H-SiC (0001) interface, only the addition of Co element can improve the interfacial adhesion energy. Bader charge analysis shows that the increase of interfacial binding energy is mainly attributed to more charge transfer.

Interfacial adhesion of ZnO nanowires on a Si substrate in air

A technique is developed for characterising the interfacial adhesion energy between a ZnO nanowire and Si substrate in air.

Molecular Dynamics Simulation on the Influences of Nanostructure Shape, Interfacial Adhesion Energy, and Mold Insert Material on the Demolding Process of Micro-Injection Molding

In micro-injection molding, the interaction between the polymer and the mold insert has an important effect on demolding quality of nanostructure. An all-atom molecular dynamics simulation method was performed to study the effect of nanostructure shape, interfacial adhesion energy, and mold insert material on demolding quality of nanostructures. The deformation behaviors of nanostructures were analyzed by calculating the non-bonded interaction energies, the density distributions, the radii of gyration, the potential energies, and the snapshots of the demolding stage. The nanostructure shape had a direct impact on demolding quality. When the contact areas were the same, the nanostructure shape did not affect the non-bonded interaction energy at PP-Ni interface. During the demolding process, the radii of gyration of molecular chains were greatly increased, and the overall density was decreased significantly. After assuming that the mold insert surface was coated with an anti-stick coating, the surface burrs, the necking, and the stretching of nanostructures were significantly reduced after demolding. The deformation of nanostructures in the Ni and Cu mold inserts were more serious than that of the Al2O3 and Si mold inserts. In general, this study would provide theoretical guidance for the design of nanostructure shape and the selection of mold insert material.

One-Dimensional Constrained Blister Test to Measure Thin Film Adhesion

A rectangular film is clamped at the opposite ends before being inflated into a blister by an external pressure, p. The bulging film adheres to a constraining plate with distance, w0, above. Increasing pressure expands the contact area of length, 2c. Depressurization shrinks the contact area and ultimate detaches the film. The relation of (p, w0, c) is established for a fixed interfacial adhesion energy.

Effect of Temperature/Humidity Treatment on Interfacial Reliability on Screen-Printed Ag / Polyimide for Advanced Embedded Packaging Technologies

The effect of temperature/humidity treatment conditions on the interfacial adhesion energy between a screen printed Ag film and a polyimide substrate was evaluated by using a 90° peel test. The measured peel strength values decrease from 254.7 N/m to 59.3 N/m after the temperature/humidity treatment at 85°CC/85% relative humidity for 500 h. X-ray photoelectron spectroscopy analysis of the peeled surfaces indicates that peeling occurs cohesively inside of the polyimide, which is closely related to both the decrease in the interfacial adhesion energy and the polyimide degradation due to weak boundary layer formation.