Showing papers on "Cobalt sulfide published in 1976"

Kinetics of hydrogen reduction of cobalt sulfide

Abstract: The hydrogen reduction of cobalt sulfide (Co9S8) at atmospheric pressure in the temperature range 600–800°C has been experimentally investigated. When sulfide pellets were used, the rate constants were overestimated. The true intrinsic kinetics of this reaction were obtained from another set of experiments using sulfide powder, under conditions such that the topochemical shrinking core model in the chemical control regime could be applied. In the temperature range 600–737°C, the rate constant for the powder reaction could be expressed as: k = 15,600 exp (–27,800/RT) Above 780°C, cobalt metal whiskers were formed, and this led to swelling and cracking of pellets. On a etudie experimentalement la reduction par l'hydrogene du sulfure de cobalt (Co9S8) a la pression atmospherique et sur une echelle de temperature variant entre 600 et 800°C. Lorsqu'on a emplye le sulfure sous forme de pastilles, il y a eu une surestimation des constantes de vitesse. La veritable cinetique intrinseque de ladite reaction a ete obtenue a partir d'une autre serie d'experiences ou l'on employait le sulfure en poudre et dans des conditions qui permettaient, dans le systeme de controle chimique, l'application du modele a noyau de retrecissement topochimique. Pour une echelle de temperatures comprise entre 600 et 737°C, on a pu exprimer comme suit la constante de vitesse dans la reaction sur le sulfure en poudre: k = 15,600 exp (–27,800RT) Au-dessus de 780°C, un pleurage (whiskers) de cobalt metallique s'est forme, lequel a conduit au gonflement et a la fissuration des pastilles.

Catalytic activation of cobalt complex imaging by cobalt sulfide

Abstract: of the Disclosure An imaging system and process wherein an element comprising a cobalt complex-developer radox system is catalyzed by cobalt sulfide. The cobalt sulfide can be imagewise produced by exposing a photoraducible cobalt complex in the presence of a thioamide, or it can be uniformly distributes and either masked in an imagewise fashion, or reacted with imagewise distributed color developing agent.