Abstract: materials can be fabricated by sintering of W-Cu composite powders. In this research W-20%wt Cu composite powderswas synthesized via a co-precipitation method. Precipitate obtained from a mixture of copper nitrate and ammoniumparatungstate (APT) in distilled water contained W-Cu compounds. This precipitate was washed, dried and calcinedat 550 of dried precipitate powder was determined...

Ceramic samples of polycomponent solid solution (Y0.96Eu0.01Sm0.01Tb0.01Er0.01)Nb0.7Ta0.3O4 have been prepared by sol–gel synthesis from fine powders obtained using nitrate solutions rare earth elements REE and coprecipitated hydroxides niobium tantalum. The structural state the initial powders’ crystal lattice has investigated. morphological features microstructure ceramics studied in dependen...

OBJECTIVES To evaluate the effect of silane application and silane heat treatment on lithium-disilicate ceramic when bonded to composite resin. METHODS Twelve blocks of lithium-disilicate (LD) ceramic were fabricated and bonding surfaces were etched using 9.5% hydrofluoric acid (90 seconds). Three experimental groups resulted from the various surface treatment combinations, which included, no...

Various procedures of mixing starting powders for hot-pressing α-SiAlON ceramics were studied. They included different milling methods (attrition milling, ball milling, and sonication), liquid medium (water, isopropyl alcohol, and pyridine), and atmospheres (ambient air and nitrogen). These mixing procedures resulted in markedly different densification behavior and fired ceramics. As the powder...

The growth of silver nanoparticles, the activation energy for silver particle growth, and the release of silver species in heat treated SiO 2 -Ag composite powders are investigated. The silver particle growth is controlled by heat treatment for 75 min of the as-synthesized SiO 2 -Ag composite powder at 300-800 °C. During heat treatment the mean size of the Ag particles increases from 10 nm up t...

OBJECTIVE Increased number of adult patients requesting orthodontic treatment result in bonding bracket to ceramic restorations more than before. The aim of this study was to evaluate and compare the shear bond strength of orthodontic brackets bonded to two types of ceramic bases with conventional orthodontic bonding resin and a new nano-filled composite resin. MATERIALS AND METHODS Twenty fo...

The microwave heating of a ceramic composite is modelled and analysed. The composite consists of many small ceramic particles embedded in a ceramic cement. The composite is assumed to be well insulated, and each particle is assumed to be in imperfect thermal contact with the surrounding cement. Based on these two assumptions an asymptotic theory exploiting the small Biot number and small non-di...

STATEMENT OF PROBLEM Ceramics are widely used for anterior restorations; however, clinical color reproduction still constitutes a challenge particularly when the ceramic crowns are used on titanium implant abutments. PURPOSE The purpose of this in vitro study was to investigate the effect of implant abutment material on the color of different ceramic material systems. MATERIAL AND METHODS F...

Novel cermet (i.e., ceramic-metal composite) membranes have been developed for separating hydrogen from product streams that are generated during coal gasification, methane partial oxidation, and watergas shift reactions. The hydrogen permeation rate in the temperature range of 600-900°C has been measured for three classes (ANL-1, -2, and -3) of cermet membranes. ANL-3 membranes provided the hi...