The results of studies on the preparation of wall tiles from pyrophyllite with silicate and phosphatic binders, with or without addition of fluxing agents, are presented. Reduction in grinding, drying and firing energies are achieved by making use of softer materials and dry blending followed by compaction and low temperature firing respectively. The process is amenable for fast firing schedules.
The addition of a boron containing compound in magnesia-carbon brick increases the oxidation resistance at high temperatures by forming a liquid phase which blocks the pores effectively. Furthermore, the presence of the magnesium-borate melt, developed in situ at high temperatures, has a strong mineralizing effect, promoting the formation and crystallization of magnesia-alumina spinel, when aluminium metal and a boron containing compounds are used simultaneously.
On presente des resultats experimentaux montrant que les paillettes de graphite peuvent occasionner une anisotropie des proprietes physiques et chimiques dans les refractaires de magnesie-graphite.
Hard porcelain samples were prepared with and without the addition of mineralizers. The concentrations of mullite, quartz and glass phases and the size as well as size-distribution of mullite crystals in the samples were determined by XRD and TEM. The electrical resistivity of the samples was measured from room temperature to 900-degrees-C and the influence of mullite and glass on the resistivity was studied. The thermal activation energy of the electrical resistivity of samples was calculated and it was shown by statistical analysis that only the concentrations of mullite and glass have a very significant effect on the electrical resistivity of the samples, the effect of mullite being opposite to that of Glass.
Le module de Young est mesure par une methode ultrasonore. La tenacite est mesuree apres condensation des echantillons; on etudie l'influence de la temperature sur les proprietes mecaniques du verre. La composition du verre etudie est: 58,13% SiO 2 -14,25% Al 2 O 3 -10,81% K 2 O-14,48% Na 2 O-0,19% CaO-0,37% MgO-1,59% LiO 2 -0,17% TiO 2
Essais de series de peintures, emails, verres, ceramiques et mortiers et ciments refractaires commerciaux comme materiaux potentiels de revetement pour la protection des tubes de chaudieres a charbon. Examen de l'adherence, de la resistance aux chocs thermiques, de la dilatation au cours de cycles thermiques et de la resistance a l'erosion des revetements
On a produit une serie de revetements ceramiques par projection dans un plasma de poudres de ZrO 2 et Al 2 O 3 . On etudie la morphologie et le coefficient de dilatation thermique des revetements, ainsi que leur resistance a l'erosion par choc de particules en fonction de l'angle d'impact, de la taille des particules, de leur vitesse et de la temperature de l'echantillon
On a etudie le comportement de quatre types de briques MgO-C contenant de 15 a 24% de carbone en contact avec trois differents types de scories a 1650°C et 1700°C sous vide
Des melanges de ciments et mortiers refractaires, avec un coefficient de dilatation thermique parfaitement ajuste a celui des aciers ferritiques pour tubes de chaudieres, ont ete choisi comme materiaux potentiels pour les revetements de protection contre l'erosion-corrosion des tubes de chaudieres a charbon. Leurs performances dans des conditions d'utilisation sont determinees
Thin film electroluminescence (EL) as exploited in display devices is discussed from the standpoint of a display user and a display technologist or engineer. An attempt is made to relate the characteristics of importance for displays to the electrical properties of the device and to the underlying physical processes or mechanisms. Particular emphasis is given to the widely used case of ZnS:Mn in a double-insulated sandwich structure. Some recent innovations relevant to display application are also described.
