The influence of various factors, such as current density, bath and annealing temperatures, on microhardness of electrodeposited nickel from a nickel sulfamateformamide bath was investigated. Bright, adherent, finegrained and almost defect-free nickel deposits with moderately high hardness were obtained at 50 "C and a current density of 0.6 Aldm2. The microhardness of the nickel deposits decrea...

R.Bęczkowski, Institute of Mechanical Technology, Czestochowa University of Technology, Poland Hardness is one of the components responsible for the resistance to wear. The development of new materials with hardness surface more than 65 HRC is possible with use welding technologies. High chromium cored wires belong to welding materials that are often used to cladding to protect surface. This ar...

The elastic and vibrational properties of iron-nickel and aluminum nanoparticles and nanocrystalline materials have been investigated on the basis of molecular dynamics simulations and the embedded atom method for the description of the materials. It is well known that nanocrystalline solids, with grain sizes in the nanometer range, exhibit often unsual properties like increased hardness due to...

Structural and dynamic properties of the building block of silica nanowires, (SiO2)6, are investigated by Born-Oppenheimer quantum molecular dynamics simulations. Thirteen conformers have been identified, seven of which have not been reported before. The energy component analysis shows that the lower electrostatic interaction differentiates the global minimum from the other structures. We also ...

Using the first-principles particle swarm optimization algorithm for crystal structural prediction, we have predicted a novel monoclinic C2/m structure for ZrB₃, which is more energetically favorable than the previously proposed FeB₃-, TcP₃-, MoB₃-, WB₃-, and OsB₃-type structures in the considered pressure range. The new phase is mechanically and dynamically stable, as confirmed by the calculat...

In this paper we study the Target Set Selection problem, a fundamental problem in computational social choice, from a parameterized complexity perspective. Here for a given graph and a threshold for each vertex the task is to find a set of active vertices that activates whole graph. A vertex becomes active if the number of activated vertices in its neighborhood is at least its threshold. We giv...

The thermal expansion behavior of a metal-formate framework, Zn(HCOO)₂·2(H₂O) (1), has been systematically studied via variable temperature single-crystal X-ray diffraction. Our results demonstrate that this formate exhibits significant negative thermal expansion (NTE, -26(2) MK-1) along its c-axis. Detailed structural analyses reveal that the large NTE response is attributed to the 'hinge-stru...

We synthesized orthorhombic FeB-type MnB (space group: Pnma) with high pressure and high temperature method. MnB is a promising soft magnetic material, which is ferromagnetic with Curie temperature as high as 546.3 K, and high magnetization value up to 155.5 emu/g, and comparatively low coercive field. The strong room temperature ferromagnetic properties stem from the positive exchange-correlat...

Single crystals of potassium para-nitrophenolate were successfully grown by the slow evaporation method with dimension of 25x10x7 mm 3 . Proton NMR spectrum was recorded to elucidate the molecular structure. Fourier transform infrared (FTIR) FT-Raman spectral studies have been performed to identify the functional groups. Structural analyses were carried out by powder x-ray diffraction pattern. ...

Motivated by a recently predicted structure of diamond-like BC₂ with a high claimed hardness of 56 GPa (J. Phys. Chem. C2010, 114, 22688-22690), we focus on whether this tetragonal BC₂ (t-BC₂) is superhard or not in spite of such an ultrahigh theoretical hardness. The mechanical properties of t-BC₂ were thus further extended by using the first principles in the framework of density functional t...