Structure and crystallization of bulk amorphous Pd41Ni10Cu28P21 alloy

Bulk amorphous Pd41Ni10Cu28P21 alloy has been prepared by water quenching method. The system shows excellent glass forming ability (GFA) with a high value of reduced glass transition temperature Trg, 0.714. Structural analyses indicate that the Pd41Ni10Cu28P21 alloy has a dense packing structure closer to "frozen liquid" than that of amorphous Pd40Ni40P20 alloy. Experiments on crystallization reveal that several crystalline phases simultaneously precipitate in the early part of crystallization. Below 710 K, a metastable phase forms, and subsequently disappears at elevated temperatures. In addition, the influence of partial substitute of Cu for Ni on GFA has been discussed with regard to thermodynamics and kinetics.     

Kinetics of glass transition and crystallization in multicomponent bulk amorphous alloys

Differential scanning calorimeter (DSC) is used to investigate apparent activation energy of glass transition and crystallization of Zr-based bulk amorphous alloys by Kissinger equation under non-isothermal condition. It is shown that the glass transition behavior as well as crystallization reaction depends on the heating rate and has a characteristic of kinetic effects. After being isothermally annealed near glass transition temperature, the apparent activation energy of glass transition increases and the apparent activation energy of crystallization reaction decreases. However, the kinetic effects are independent of the pre-annealing.     

Formation of new Zr-Ti-Cu-Ni-Be-C bulk amorphous alloy

The formation of the new bulk amorphous Zr-Ti-Cu-Ni-Be-C alloy with high strength is reported. The effects of the small size atoms on the glass forming ability, strength and thermal stability of the amorphous alloy are investigated. The formation mechanism of the bulk amorphous alloy is discussed.     

Formation and performance of new Zr-Ti-Cu-Ni-Be-Fe bulk amorphous alloy

The formation of the new Zr-Ti-Cu-Ni-Be-Fe bulk amorphous alloy with high strength is reported. The effects of the iron atom on the glass forming ability, hardness, susceptibility and thermal stability of the amorphous alloy are investigated. The role of the iron in the formation of the bulk amorphous alloy is discussed.     

Liquid structure of undercooled Cu70Ni30 alloy

Experiments of X-ray diffraction for liquid Cu₇₀Ni₃₀ alloy above and below its liquidus (l 230°C) have been carried out. By the analysis of experimental results, it is discovered that difference between structures of liquid and undercooled Cu₇₀Ni₃₀ alloy is their cluster sizes. The correlation radius of cluster is 1.125 nm and the atom number of cluster is 403 at l 250—l 400°C, and they are 1.3 nm and 704 respectively at the undercooled liquid state (1 200°C). The structure of liquid Cu₇₀Ni₃₀ alloy is fcc short order and its solid structure, fcc, is kept from liquid fcc short order.     

Effect of Mg and C contents in MgCNi3, and structure and superconductivity of MgCNi3- x -Co x

The effect of Mg and C contents on T_C in MgCN₃, and structure and superconductivity of MgCNi_3-x Co _x were studied. It is found that the excess of Mg and C in initial material mixture is favorable to improvement inT _c and helps to obtain single-phase samples. For preparing MgCNi₃ superconductor, the optimum composition of starting materials is MgC_1.45Ni₃ with excess of Mg (20 wt.%) of the stoichiometric composition. In gCNi_3-x Co _x system, a continuous solid solution is formed, lattice parameter decreases slightly andT _c decreases obviously with increasingx. A suppression of superconductivity is observed due to the substitution of Co (Mn) for Ni. The suppression effect is smaller for the substitution of Co than that of Mn     

Application and validation of a comprehensive model for PM10 and PM2.5 concentrations in Belgium and Europe

PM₁₀ and PM_2.5 concentration in Belgium and its surrounding countries were simulated for 2002 by means of the air quality model EUROS. The EUROS model simulates the transport and chemistry of gaseous species as well as the formation of fine particles. The paper describes the mathematical formulation of the partial differential equations used in the model and briefly discusses the main numerical solution techniques. The extension of the model with two modules for the calculation of atmospheric aerosol particles is lined out. The modelled concentrations for 2002 are compared with measured PM₁₀ concentrations in an urban background station in Brussels. Results show that the trends in the PM₁₀ time series are well represented. However, the model substantially underestimates the actual measured concentrations due to the fact that the emission inventories do not include all of the known sources of primary PM₁₀ emissions. The geographical pattern of PM₁₀ as observed over Belgium is well reproduced by the model.