the above description of some of the aspects of the invention the hydrazine compounds which can be utilized in the practice of this invention are water soluble hydrazine compounds of the formula h 2 n nr 1 r 2 wherein r 1 and r 2 are each selected from the group consisting of hydrogen and lower alkyl by lower alkyl as used herein it is meant that the group contains from 1 to 4 carbon atoms preferred hydrazine compounds include hydrazine hydrates of hydrazine containing various percentages of water methyl hydrazine and unsymmetrical dimethyl hydrazine for these hydrazine monohydrate is preferred while any cobalt source that is at least soluble to the extent of about 1 gram per 100 cc of water at 25 u00b0 c can be used it is generally preferred to use cobalt carbonate since it offers certain economic advantages additionally during the subsequent reaction which occurs carbon dioxide evolves from the slurry thus no potential contaminating material remains in the slurry although any buffering agent can be used which can achieve a ph greater than 7 can be used potassium carbonate and sodium carbonate are the preferred materials although the strength of the reactants in the aqueous slurry which is formed can be varied over quite a large range and achieve the benefits of this invention it is generally preferred to use a concentration of cobalt and hydrazine compounds which will yield a total reactant strength of from about 5 to about 25 by weight of the aqueous slurry although it is not an essential characteristic of the slurry generally a cobalt to nitrogen molar ratio of about 1 1 is preferred cemented refractory metal carbides are known in the art a refractory metal such as tungsten titanium tantalum and.