Papers by Keyword: Surface Analysis

Abstract: Electron backscatter diffraction (EBSD) conventionally necessitates the preparation of flat, damage-free surfaces, typically achieved through mechanical or chemical polishing. However, for porous materials susceptible to fracture, such procedures are not only technically challenging but also risk altering or obscuring critical microstructural features, particularly at fine length scales. Despite the widespread reliance on surface polishing, its necessity in EBSD analysis—especially for highly porous materials—has seldom been critically examined, and studies omitting such preparation remain scarce. In the present study, EBSD analysis was conducted on porous polycrystalline YBa₂Cu₃O_y without any surface treatment. The absence of polishing preserved the pristine microstructure, free from artifacts commonly introduced by conventional preparation techniques. Although the surface topography limited the number of pixels yielding high-quality diffraction patterns, orientation imaging revealed that the surface granules predominantly exhibit single-crystalline domain structures. These findings demonstrate that EBSD can be successfully applied to porous materials without surface polishing, thereby providing a rapid, non-destructive approach for microstructural characterization while preserving the material’s intrinsic structural integrity.

Abstract: In this study, we investigated the effect of the post-etch cleaning of GaAs surfaces. We found that a plasma damage layer was formed on GaAs surfaces by dry etching, and an As-rich layer remained after post-etch cleaning. The As rich layer needs to be removed because it is replaced by micron-sized particles when stored in an air. We also found that a pure GaAs surface can be obtained by performing additional cleaning consisting of oxide formation and removal.

Abstract: This study examines the influence of tool eccentricity pin positioning on AA6061 aluminium alloy friction stir welds. A laser scanning confocal microscope and optical microscope was used to analyze the surface roughness and the cross-sectional microstructure of the samples. Surface roughness analysis reveal the thread-to-flat (T2F) samples show rougher surface with increasing rotational speed up to 1400 rpm. On the other hand, the surface appearance of flat-to-thread (F2T) samples show minimal change. Cross-sectional microstructural observations show that the stir zone area of both groups increases with increasing rotational speed. However, the periodic bands in T2F and F2T samples increases in the upper region and lower region of the stir zone, respectively.

Abstract: Paperboard package properties can be improved by embossing functional features on package surfaces. Embossing is used in package manufacturing as an additional tool to improve the appearance of the packages. It can also be used to increase product safety by improving functionality and identifiability of packages. Creation of features directly on the base material without implementing additional components improves the sustainability level of package applications. To evaluate functionality of features, such as protective surface patterns, in the applicable practice, the following steps need to be gone through; design phase, tool manufacturing phase, pattern production phase and analysis phase. Bespoken toolsets were designed and manufactured to form a protective frame around commercial radio-frequency identification tag (RFID). The essential process parameters in the embossing experiments were the pressing force and the plate temperature which were optimized in preliminary tests. Methods for evaluating the performance of created embossed patterns were wear testing of package surfaces, topography measurement with a 3D profilometer and SEM-imaging for more detailed analysis. The results show that embossing is a suitable manufacturing method for creating targeted functional features on paperboard surfaces. With the formed surface features, the functionality of the packages was improved by protecting the identification labels.

Abstract: In this work, we characterized the wet chemical atomic layer etching of an InGaAs surface by using various surface analysis methods. For this etching process, H₂O₂ was used to create a self-limiting oxide layer. Oxide removal was studied for both HCl and NH₄OH solutions. Less In oxide tended to remain after the HCl treatment than after the NH₄OH treatment, so the combination of H₂O₂ and HCl is suitable for wet chemical atomic layer etching. In addition, we found that repetition of this etching process does not impact on the oxide amount, surface roughness, and interface state density. Thus, nanoscale etching of InGaAs with no impact on the surface condition is possible with this method.

Abstract: High temperature applications of self-lubricated sliding surfaces have gained industrial importance during the recent years. One popular system is based on sintered Ni-Cr composites with addition of solid lubricants. In the present work these composites were prepared under controlled sintering conditions with different combinations of solid lubricants (MoS₂, Ag and CaF₂) at 1200 °C under flowing argon. The physical properties such as sintered density, relative density and porosity were studied. The microstructures and phase studies of the Ni-Cr based composites were conducted using SEM analysis while the hardness of the composites was measured by Vickers Micro Hardness Tester. The friction tests were conducted with ball on disc configuration following ASTM G-99-95a standard. The MoS₂ solid lubricant provides best lubrication at room temperature which is demonstrated by a low friction coefficient compared to pure Ni-Cr composites. The SEM pictures of worn out tracks show solid debris distribution, and filling of pores with solid lubricant phases. The time taken for stabilization of friction coefficient also varies with the type of solid lubricant. Dual and multiple additions of solid lubricants are also able to reduce the friction of coefficient compared to pure Ni-Cr composite.

Abstract: The paper presents the results of a SEM/EDS and XPS study of changing of chemical and phase composition of the friction surfaces Fe-Mn-C-B-Si-Ni-Cr hardfacing coatings depend on depth. The tribological examination was conducted in a pin-on disc system with unitary pressure of 10 MPa under dry friction conditions. A scanning electron microscope SEM/EDS as well as X-Ray photoelectron spectroscopy (XPS) were used to examine the structures on the friction surface and depend on depth 5, 10, 15, 20, 50, 100, 200, 6000 nm. The presence of compounds such as oxides (B₂O₃, SiO₂, Cr₂O₃), carbides (Fe₃C, Cr₇C₃), borides (FeB, Fe₂B).

Abstract: In this study, attempt has been made to investigate the effect of SiC particles on the friction and wear properties of Ni/SiC composites manufactured by electrodeposition, especially for the composites with high-temperature treatment.For this purpose, α-Al₂O₃ was coated on the surfaces of SiC particles by sol-gel technology to inhibit interfacial reaction of SiC and nickel at high temperature. Both of the Ni/α-Al₂O₃-coated SiC (Ni/CS_p) and Ni/uncoated SiC (Ni/UCS_p) composites were treated at 600 °C to study the resulting wear behaviour. The results indicated that with heat treatment at 600 °C, the Ni/CS_p composite had better tribological properties than the Ni/UCS_p composite. It was proved that the uncoated SiC particles have reacted completely with nickel leaving many defects, while the coated SiC particles still remained in the Ni/CS_p composite hardening the nickel matrix and supporting the counterpart, thus improving the wear resistance of Ni/CS_p composite with relatively low friction coefficient and wear mass loss compared to the Ni/UCS_p composite.

Abstract: Biochar was derived from the crop residue as multifunction materials for agriculture purposes and a soil amendment to improve soil fertility. Rubber wood sawdust (RWSD) was heated slowly inside the vertical furnace for an hour at temperatures ranging from 300 °C to 700 °C. The aim of this study is to investigate the influence of pyrolysis temperatures on the physiochemical properties of the biochar. The properties of biochar were characterized using X-ray diffraction (XRD) and scanning electron microscope (SEM) attached with Energy Dispersive X-ray for elemental analysis. It was found that pore size distribution was more uniform on samples heated at higher temperature (700 °C). The SEM-EDX analysis confirmed the O:C ratio was directly proportional to the heating temperature. These means that slow pyrolysis of RWSD at 700 °C could produce biochar of greater cation exchange capacity (CEC) that important for soil fertility improvement.

Abstract: In this paper we report an approach for the structural analysis of mineral-collector interfaces of (bio) flotation systems by means of attenuated total reflection Fourier-transform infrared spectroscopy (ATR FT-IR). The extraction of rare earth metals from electronic waste materials is an important challenge for the recycling industry. In a current project bacteriophage are used as biocollectors to develop a bioflotation model system for the separation of lanthanum phosphate doped with cerium and terbium (LaPO₄:Ce³⁺,Tb³⁺) from mixed fluorescent phosphors. As an initial analytical concept fluorescence microscopy was successfully applied to investigate particles of spent fluorescent lamp powders and to visualize the bacteriophage on the surface of the waste material. However, due to the restrictions of this technique we are not able to identify the molecular interactions of the bacteriophage with the recycled material. ATR FT-IR was found to be an effective tool to detect the major coat protein of the bacteriophage biocollectors on the surface of the LaPO₄:Ce³⁺,Tb³⁺ and sense their specific bonding interaction opening the gates for the high level chemical characterization of the interface.