Preparation of Ultrafine CVD WC Powders Deposited from WCl6 Gas Mixtures

Preparation of Ultrafine CVD WC Powders Deposited from WCl6 Gas Mixtures

Ultrafiie WC powders were produced from WCla-C3Hs-H2 gas mixtures in a conventional tubular hot-wall downstream CVD reactor. At reaction temperatures between 1100 and 1550°C powders containing W, WZC, WC and carbon were produced. The overall chemical compositions of the tungsten coinpounds as well as the free carbon contents depended strongly on the reaction temperature and the ratio of the rea...

Aqueous Processing of WC-Co Powders

Electrochemical properties of mixed WC and Pt-black powders

The electrochemical characteristics of a mixture of Pt-black and WC powders and its catalytic activity for methanol and formic acid oxidation were investigated in acid solution. XRD and AFM measurements revealed that the WC powder employed for the investigation was a single-phase material consisting of crystallites/spherical particles of average size of about 50 nm, which were agglomerated into...

Modelling the Sublimation-Desublimation Processes for Production of Ultrafine Powders

The purpose of this work is to establish the theoretical foundations for calculating and designing the sublimationcondensation processes in chemical apparatuses which are intended for production of ultrafine powders of crystalline and amorphous materials with controlled fractional composition. Theoretic analysis of the primary processes of nucleation and growth kinetics of the clusters accordin...

In-situ Polymer Grafting on Ultrafine Metal Powders

Ultrafine aluminum and boron powders have been identified as very promising fuels as part of energetic materials formulations. However, the large specific surface area that gives these powders a high reactivity also makes them particularly difficult to maintain in an unoxidized state. They also agglomerate easily during compounding processes. The coating of the particles by a polymer could offe...