Hardness Measurement and Evaluation of Double-layer Films on Material Surface

A method for hardness measurement and evaluation of double-layer thin films on the material surface is proposed. Firstly, it is studied how to obtain the force-indentation response with the finite element method when the indentation is less than 100 nanometers, in which current nanoindentation experiments have no reliable accuracy. The whole hardness-displacement curve and fitted equation are obtained. At last, a formula to predict the hardness of the thin film on the material surface is derived and favorably compared with experiments.

Double-layer indium doped zinc oxide for silicon thin-film solar cell prepared by ultrasonic spray pyrolysis

Indium doped zinc oxide （ZnO：In） thin films were prepared by ultrasonic spray pyrolysis on corning eagle 2000 glass substrate. 1 and 2 at.% indium doped single-layer ZnO：In thin films with different amounts of acetic acid added in the initial solution were fabricated. The 1 at.% indium doped single-layers have triangle grains. The 2 at.% indium doped single-layer with 0.18 acetic acid adding has the resistivity of 6.82 × 10^-3 Ω. cm and particle grains. The doublelayers structure is designed to fabricate the ZnO：In thin film with low resistivity （2.58 × 10^-3 Ω. cm） and good surface morphology. It is found that the surface morphology of the double-layer ZnO：In film strongly depends on the substratelayer, and the second-layer plays a large part in the resistivity of the doublewlayer ZnO：In thin film. Both total and direct transmittances of the double-layer ZnO：In film are above 80% in the visible light region. Single junction a-Si：H solar cell based on the double-layer ZnO：In as front electrode is also investigated.

Annealing of Oriented PP/PE Double-layer Film within the Melting Range of PE:the Role of Partial Melting and Self-nucleation

Due to the mechanical stability of the PP layer,the oriented PP/PE double-layer film with a row-nucleated crystalline structure can be annealed at a higher temperature than the PE monolayer film.In this work,the effects of annealing temperature within the melting range of PE on the crystalline structure and properties of PP/PE double-layer films were studied.When the annealing temperature is between 100 and 130℃,below the melting point of PE,the crystallinity,the long period,lateral dimension and orientation of the lamellae in the PE layer increase with the annealing temperature due to the melting of thin lamellae and the self-nucleated effect of partially-melted melts during annealing.With the annealing temperature further increasing to 138℃,near the melting ending point of PE,since the lamellae melt completely and the melt memory becomes weak during annealing,some spherulite structures are formed in the annealed sample,resulting in a decrease of orientation.In contrast,the annealing only causes the appearance of a low-temperature endothermic plateau in the PP layer.The improved size and orientation of lamellar structure in the PE layer increase the pore arrangement and porosity of the stretched PP/PE microporous membrane.This study successfully applies the self-nucleation effect of partially-melted polymer melt into the practical annealing process,which is helpful to guide the production of high-performance PP/PE/PP lithium batteries separator and the annealing process of other multilayer products.

Controllable formation of periodic wrinkles in Marangoni-driven self-assembled graphene film for sensitive strain detection

Controllable formation of microstructures in the assembled graphene film could tune the physical properties and broaden its applications in flexible electronics.Many efforts have been made to control the formation of wrinkles and ripples in graphene films.However,the formation of orderly wrinkles in graphene film remains a challenge.Here,we reported a simple strategy for the fabrication of graphene film with periodic and parallel wrinkles with a pre-stretched polydimethylsiloxane substrate.The width of the wrinkles in graphene can be controlled by changing the pre-stretched strain of the substrate.The average width of wrinkles in graphene film on the substrate with pre-stretched strain of 10%,20%,and 50%was about 3.68,2.99 and 2.01µm,respectively.The morphological evolution of wrinkled double-layered graphene under mechanical deformation was observed and studied.Furthermore,a strain sensor was constructed based on the wrinkled graphene,showing high sensitivity,large working range and excellent cyclic stability.These strain sensors show great potential in real-time motion detection,health surveillance and electronic skins.

High corrosion resistance film on rebar by cerium modification

A cerium film was prepared on the surface of rebar by chemical conversion method to enhance its corrosion resistance.The film in the simulated concrete pore solution was measured by electrochemical method,transmission electron microscope(TEM)and X-ray photoelectron spectroscopy(XPS).The effect of temperature on film formation was studied,and the optimum temperature was determined at 35℃.The film produced by too high formation temperature has more defects,resulting in the lower corrosion resistance.The Ce film resistance increased with time evolution until 800 h,then decreased and stabilized.The Ce film layer has a double-layer film structure,the upper layer is an oxide of cerium,and the underlayer is an oxide of iron.Results revealed that after being immersed in the simulated concrete pore solution,the corrosion resistance of the Ce film was enhanced by self-densification.

Corrosion of Nickel-based Alloy G30 in the Stratum Water Containing H2S/CO2

The influences of temperature and CO2 pressure on the corrosion of nickel-based alloy G30 in the stratum water containing H2S/CO2 were investigated with the aid Mott-Schottky analysis and scanning electron microscopy（SEM） of electrochemical impedance spectroscopy（EIS）, The results indicate that alloy G30 is in the passive state in the stratum water, which is related to the formation of the passive film on its surface. This passive film can significantly protect the substrate from further corrosion. And the film protection is enhanced with decreasing temperature and CO2 pressure. Auger electron spectrometry（AES） and X-ray photoelectron spectrometry（XPS） results reveal that the passive film shows the double-layer structure, i.e. the inner chromium oxide and the outer iron/nickel spinel oxides or hydroxides with Mo oxides dispersing throughout the inner and outer scale.