Characterization of the µ and P phase precipitates in the CMSX-4 single crystal superalloy.

A combination of scanning electron microscopy (SEM), transmission electron microscopy (TEM) and scanning-transmission electron microscopy (STEM) using high-angle annular-dark-field (HAADF) imaging, focussed ion beam- scanning electron microscopy (FIB-SEM) tomography, selected area electron diffraction with beam precession (PED), as well as spatially resolved energy-dispersive X-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS), was used to investigate topologically close-packed (TCP) phases, occurring in the CMSX-4 superalloy subjected to high temperature annealing and creep deformation. Structural and chemical analyses were performed to identify the TCP phases and provide information concerning the compositional partitioning of elements between them. The results of SEM and FIB-SEM tomography revealed the presence of merged TCP particles, which were identified by TEM and PED analysis as coprecipitates of the µ and P phases. Inside the TCP particles that were several micrometres in size, platelets of alternating µ and P phases of nanometric width were found. The combination of STEM-HAADF imaging with spatially resolved EDS and EELS microanalysis allowed determination of the significant partitioning of the constituent elements between the µ and P phases.

Antireflection TiO x Coating with Plasmonic Metal Nanoparticles for Silicon Solar Cells.

It is known that the light scattering from the metal particles deposited on the surfaces of cells can be used for increasing light trapping in the solar cells. In this work, plasmonic structures are composite materials that consisted of silver nanoparticles embedded in dielectric films of TiO x -used as cell antireflection coating. The films are deposited by sol-gel method using spin-on technique. Microstructure of prepared samples is analyzed by SEM observation. Good homogenity and particles density was obtained by this simple, cheap, and short time-demanding method. We demonstrate that due to light scattering by metal particles, the plasmonic-ARC layer is more effective than TiO x layer without Ag nanoparticles. Implementation of nanoparticles on bare cell surface was carried out too. The influence of the plasmonic structures on the silicon solar cells parameters is presented as well. We announce about 5 % additional growth in short circuit current for cells with nanoparticles.