Showing papers in "Ceramurgia International in 1977"

TL;DR: In this article, the formation and stability of tetragonal ZrO 2 powders are closely related to its particle size, and it was found that there is a critical particle size below which the TZO 2 is stable thermodynamically.

TL;DR: In this paper, conditions and mechanisms under which both configurations develop are discussed and illustrated by experiments on MgO powder compacts that density considerably more rapidly in flowing water vapor than in static air.

TL;DR: In this article, the formation of pyrochlore structure compound Gd 2 Hf 2 O 7 (a = 10,498 A) was found, which undergoes an order-disorder transformation at very high temperature to yield a fluorite-type structure.

TL;DR: In this paper, a modified van Arkel-de Boer apparatus on SiC-covered graphite and molybdenum susceptors was used to obtain the morphology and structure of SiC products obtained at temperatures between 1400 and 1900°C and input gas flow rates between 5.10−4 and 6.2 moles per hour.

TL;DR: For single-phase lime and magnesia and also for two-phase doloma (consisting essentially of a dispersion of MgO crystals in a lime crystal matrix), the creep rate, ϵ, varies with stress, σ, and temperature, T, as ϵ = A σ n exp ( − Q c RT ) where A and n are constants and Qc is the activation energy for creep as discussed by the authors.

TL;DR: Pellyite, Ba 2 Ca(Mg, Zn, Fe 2+, Co) 2 Si 6 O 17, is a framework sillicate containing three essential divalent ions as mentioned in this paper.

TL;DR: Transparent PLZT ceramics were fabricated by a new vacuum-atmosphere sintering method combining vacuum and atmosphere sinterings as discussed by the authors, which was used to produce nearly colourless small grain -size samples.

TL;DR: In this article, the densification of batches containing partially synthesized spinel powders with addition of CaO and SiO 2 mixtures was enhanced, and the densities after 1600°C were equal to those after 1800°C, without additions.

TL;DR: In this article, the phase relationship at 1100°C among reaction products of BaO, CaO and Fe 2 O 3 was determined by the air quenching technique, and two binary solid solutions were formed, one between barium hexaferrite and a hypothetical calcium tetraferrite and another pseudobinary one adjacent to 2BaO·Fe 2 O3.

TL;DR: In this paper, the possibility of obtaining porcelain bodies with much better properties than present industrial ones, and at the same time with a significant saving in the cost of raw materials.

TL;DR: A review of the factors affecting the basic properties of ceramic slips, i.e. viscosity, settling rate, tixotropy and dilatancy, is given in this paper.

TL;DR: In this paper, the dielectric properties of ceramics in the system ( Sr 1− x Ca x {( Li 1 4 Nb 3 4 ) 1− y Ti y } O 3 were investigated.

TL;DR: In this paper, the growth of a sodium beta - alumina powder (nominal composition Na2O · 8.5Al2O3; impurity content < 0.3w/0) was reported.

TL;DR: In this article, the results of a study into plasma-sprayed coatings of W and Cr- carbides are presented, consisting of phase composition, microstructure, carbon losses, hardness and scratch resistance of coatings obtained at the same spraying conditions.

TL;DR: In this paper, the development of a fabrication route for europia, which is one of the few materials suitable for use as a neutron absorber in Fast Reactor control and shut-off rods, is described.

TL;DR: In this article, the influence of various +2, +3 and +5 valent dopants was analyzed and it was concluded that oxygen vacancies are the predominant type of defect in slightly understolchiometric rutile.

TL;DR: In this paper, a thin layer of a cobalt phosphorus or nickel phosphorus alloy was added to barium ferrite powders by chemical reduction from aqueous solutions with hypophosphite, after the usual sensitization activation pretreatments.

TL;DR: In this article, the present state of the technology of slurry preparation for making anisotropic hexaferrite magnets is discussed, with the main conclusion that cheaper and less defined raw materials can be used, provided a flexible technology and the existing knowledge on raw materials and phenomena during prefiring are applied.

TL;DR: In this article, the authors review advances in the understanding of the hot forming of ceramic materials and the mechanisms of sintering during the intermediate and final stages of densification during hot pressing.

TL;DR: In this paper, hot pressing of two sodium beta-alumina powders of nominal composition Na 2 O · 6.9Al 2 O 3 and Na 2 o · 8.5Al O 3 at 1100 − 1600°C and 150 − 350 kg/cm 2 in inductively heated graphite dies under vacuum, proved an easy method for obtaining fully dense materials in very short pressing times.

TL;DR: In this article, the authors demonstrate that it is possible to reduce the energy consumption within a furnace using a zirconia heating element working up to 2000°C in an oxidizing atmosphere.

TL;DR: In this article, the interface of metal-to-alumina ceramic seals was examined by an electron probe and by X-ray methods, and the thickness of the interface was found to be 11 to 15 μm.

TL;DR: In this article, a short description of high-porosity brick production was given, which included the preparation of starting materials, forming by extrusion, firing and finishing, and included physical, thermal, structural and microstructural measurements.

TL;DR: In this paper, a review of possible ways to synthesize mullite and cordierite on a large production scale is given, using bentonite and concentrated Al 2 (SO 4 ) 3 and MgSO 4 as precursors.

TL;DR: In this paper, the shrinkage properties of calcite bricks made from ground limestone masses containing CaCl 2 have been studied using simplified systems, including some additives specially chosen; an explanation is offered based on shrinkage data and the observed development of a unique microstructure, resulting from an early formation of a reactive liquid as well as gas evolution effects.

TL;DR: In this article, the microstructure of this porcelain is unusual; it consists of a glassy matrix containing spherical mullite, and it has outstanding properties: high strength combined with high thermal shock resistance.