Process of obtaining WC -co nanostructured powders from the precursor to ammonium paratungstate (apt) through solid gas reaction.

摘要

"Obtaining composite WC -co -nano -studied powders from the precursor of ammonium paratungstate (apt) through gas -solid reaction": the composite WC -co powder was synthesized from the precursor of ammonia paratungstate (apt). The cobalt element was introduced through the dissolution of cobalt nitrate in ammonium paratungstate aqueous solution. In order to reduce the transfer of cobalt to filtrate, cobalt nitrate has been dissolved into ethanol. After filtration,The precipitate has been washed to eliminate nitrate tones and dried in oven mufla to 90.C. The precursor formula is 5 [(nh ~4 ~1 ~ sym co sym , sym ~2 ~o.12o ~3 ~. Nh12o ~2 ~of which two compositions were prepared for x = 0885 and x = 1992 respectively corresponding concentration of 10 - and 20% cobalt. The precursor has been characterised by analysis, differential thermal (dta),Gravimetric thermal (atg) and infrared (iv). The carboreduction reaction was performed under the atmosphere of methane and hydrogen. The precursor was subjected to methane /hydrogen mixture containing 5%of ch ~4 ~ which flows at 10 (i /h through the reactor. The heating process starts from 25 to 500 (c) flowing from 5 (1 /h to 5 (c) and from 500 to 850 (c) flowing from 1 /h to ch ~4 ~ and 9 /l /h from H ~2. When reaching the 850 (c) isotherm, the samples are at this temperature for two hours. The product obtained (wc -co) h as been characterised by X -ray diffraction (drx),Electronic scanning microscopy (mev) and laser granulometry.