Temperature stable dielectric properties for Pb(Mg1/3Nb2/3)O3-BaTiO3-PbTiO3 system ceramics

Abstracts are not published in this journal This revised version was published online in November 2006 with corrections to the Cover Date.     

The substitution-site of Cd2+ in Pb(Ni1/3Nb2/3)O3-PbZrO3-PbTiO3 ceramics

Abstracts are not published in this journal This revised version was published online in November 2006 with corrections to the Cover Date.     

Effect of high pressure on the dielectric properties of relaxor compositions [Pb(Fe1/2Nb1/2)O3]1-x-y-[Pb(Zn1/3Nb2/3)O3]x- [BaTiO3]y

Abstracts are not published in this journal     

Characterization of (Bi1/2Na1/2)TiO3 using electric modulus spectroscopy

Abstracts are not published in this journal This revised version was published online in November 2006 with corrections to the Cover Date.     

Multiple-toughening behaviour in SiC platelet-reinforced TZP/Al2O3 ceramic composites

Abstracts are not published in this journal This revised version was published online in November 2006 with corrections to the Cover Date.     

Stabilization of the perovskite phase in Pb(Zn1/3, Nb2/3)O3 ceramics modified by Ba(Zn1/3, Nb2/3)O3 and BaTiO3

Stabilization of the perovskite phase in PZN-BT-BZN ceramics prepared by solid-state sintering was investigated. With the addition of BT and/or BZN, the amounts of perovskite phase in PZN ceramics increased, but the amount of pyrochlore phase decreased. Optimum calcination conditions for this system, to obtain PZN ceramics with the minimum amount of the pyrochlore phase, are a temperature range between 950 and 1000°C and a sintering time of 2–4 h. The perovskite phase of these systems could be 100% stabilized by the addition of more than 7 mol% BT, 8 and 10 mol% BTZN and BZN, respectively. This revised version was published online in November 2006 with corrections to the Cover Date.     

Synthesis and superconducting properties of the composite in the system (1_x).YBa2Cu3Oy − x.Ba(Y1/2Nb1/2)O3

Abstracts are not published in this journal This revised version was published online in November 2006 with corrections to the Cover Date.     

Structural order in Ba(Zn1/3Ta2/3)O3, Ba(Zn1/3Nb2/3)O3 and Ba(Mg1/3Ta2/3)O3 microwave dielectric ceramics

The process and nature of structural ordering and the factors that influence them have been investigated in the microwave dielectric perovskites, barium zinc tantalate (BZT), barium zinc niobate (BZN), and barium magnesium tantalate (BMT), sintered at various temperatures. The samples were characterized mainly by X-ray powder diffraction and transmission electron microscopy. The results show that short-range 1 : 1 B-site order features strongly in the early stages of ordering in BZT and BZN, but it is extremely rare in BMT, for which most grains commence with 1 : 2 order. As sintering progresses, 1 : 1 order is replaced by 1 : 2 long-range order in BZT and by disorder in BZN. Orientational variants of the ordered domains within grains occur in similar numbers when order is fine-scale, but their distribution is less homogeneous in well-ordered samples. Local inhomogeneities in the degree of order within grains, which will affect dielectric properties, correlate with both residual non-stoichiometry and the presence of dislocations. Incompletely reacted starting materials which may persist to late stages of sintering can also strongly influence order. Anomalously large ordered domains at grain boundaries are attributed to grain-boundary migration accompanied by enhanced diffusion. The results indicate that with starting materials that are well-mixed and homogeneous at the nanoscale, tailoring of physical properties should be possible by controlling the type and degree of order through chemical composition. This revised version was published online in November 2006 with corrections to the Cover Date.     

Multiple-toughening behaviour in SiC platelet-reinforced TZP/Al2O3 ceramic composites

Abstracts are not published in this journal     

In situ synthesis of Al3Niw/Al composites under high pressure

Abstracts are not published in this journal     

Hybrid plasma chemical vapour deposition of aluminium nitride from Al and NH3/N2 mixtures

Abstracts are not published in this journal This revised version was published online in November 2006 with corrections to the Cover Date.     

Review of proposed defect structures in LiNbO3

The problem of native defect structure in LiNbO₃ is discussed in the light of experimental data published till now. An attempt of uniform interpretation of these data has been undertaken.     

Preparation and characterization of nano-structured monolithic SiC and Si3N4/SiC composite by hot isostatic pressing

Abstracts are not published in this journal This revised version was published online in November 2006 with corrections to the Cover Date.     

Time dependence of dielectric constants of Pb(Mg1/3Nb2/3)O3-BaTiO3-PbTiO3 ferroelectric ceramics for X7R MLCs

The isothermal ageing behaviour of Pb(Mg_1/3Nb_2/3)O₃-BaTiO₃-PbTiO₃ ceramics, promising high dielectric (ε_25°C = 4574) materials for X7R multilayer ceramic capacitors (MLCs) was studied over a wide range of frequencies. During ageing, the dielectric constants and loss tangents decreased linearly with the logarithm of ageing time. The ageing rates were evidently influenced by the test frequencies. The maximum value, within the range 0.1 to 1000 kHz, was about 1.7% per decade (time) and meets the corresponding ageing specifications for X7R ceramic dielectrics. This revised version was published online in July 2006 with corrections to the Cover Date.     

Dielectric properties of (1 ? x)KNbO3 · xBiZn2/3Nb1/3O3 (x ≤ 0.4) perovskite solid solutions

(1 − x)KNbO₃ · xBiZn_2/3Nb_1/3O₃ ceramic materials have been prepared by solid-state reactions. The materials with x < 0.5 have been shown to be phase-pure perovskite solid solutions. Their average lattice parameter increases linearly with x. Below 300 K, the solid solutions with 0.1 < x ≤ 0.4 are ferroelectric relaxors. M″-M′ diagrams, representing the relationship between the real and imaginary parts of the complex electric modulus, have been used to evaluate the Curie temperature of the solid solutions and the temperature of their transition to the paraelectric phase. The Arrhenius plots of dc conductivity for the solid solutions show breaks corresponding to their phase transitions. Below 400 K, the dc conductivity is low, and its contribution to the dielectric response of the solid solutions is insignificant. Original Russian Text ? I.I. Moroz, N.M. Olekhnovich, Yu.V. Radyush, A.V. Pushkarev, 2008, published in Neorganicheskie Materialy, 2008, Vol. 44, No. 6, pp. 747–753.     

Phase diagram of the binary system PbO-Ga2O3

The phase diagram of the binary system PbO-Ga₂O₃ was determined by means of DTA and X-ray measurement. The existence of compound PbGa₂O₄ in the investigated system was confirmed. The compounds Pb₂Ga₂O₅ and PbGa₁₂O₁₉ recently published were not found.     

Mössbauer study of amorphous Al2O3:Eu3+

Abstracts are not published in this journal This revised version was published online in November 2006 with corrections to the Cover Date.     

Preliminary data on solid solubility between LaCrO3 and LaFeO3 or LaMnO3

Abstracts are not published in this journal     

Determination of matrix and precipitate elastic constants in (γ–γ′) Ni-base model alloys, and their relevance to rafting

A complete set of high-temperature data relevant to rafting, i.e. the elastic constants of the individual γ and γ′ phases and the elevated temperature lattice mismatch between the phases, was generated for two model ternary Ni–Al–Mo single crystal alloys. The directionality of rafting was examined experimentally in the same alloys upon uniaxial loading in compression and tension along a 100 cube axis. The key material properties and corresponding directional coarsening observations are discussed in view of the various models for rafting published in the literature.     

On the luminescence of SrTiO3 and related titanates

A comparison is made between the recently published luminescence of some semiconducting titanates (TiO₂, SrTiO₃, BaTiO₃) and the luminescence of mixed metal oxides containing isolated titanate groups. This comparison shows that part of the assignments of the emissions of the former group of compounds is doubtful. Alternative proposals are made.