| 摘要 |
<p>A tungsten free hard alloy consists of titanium diboride, titanium carbide and a binding agent. The tungsten free hard alloy contains as a binding agent at least one of the metals of subgroup IB of the periodical system which are inactive to boron or an alloy based on one of those metals. The components ratio of the tungsten free hard alloy is the following in% by mass: titanium diboride ........ 40-60, binding agent.............. 3-30, titanium carbide......... balance The tungsten free hard alloy of the said composition has a porosity of no less than 1%. The method of making the tungsten free hard alloy comprises preparing an initial blend by mixing the titanium, boron and carbon powders, pressing them, a setting local fire to the blend to initiate an exothermic reaction of titanium with boron and carbon, the reaction then proceeding by itself in the combustion regime and spreading throughout the whole of the blend due to the heat transfer from the heated layers of the blend to the cold ones. During the preparation of the blend, are added to it, either the powder of at least one of the metals of subgroup IB of the periodical system which are inactive to boron or the powder of an alloy based on one of those metals or the powders of metals which form the said alloy under the conditions of the said exothermic reaction. After finishing the exotermic reaction the thus obtained hard-liquid reaction mass is then pressed up to reacting a porosity of less than 1%. </p> |
