Abstract: A process and related compositions for lowering the electrical resistivity of ZrB.sub.2 are described. In a preferred embodiment, ZrH.sub.2 or Zr powder is blended with the ZrB.sub.2 powder and the composite is vacuum hot pressed at 2100.degree. C. The elemental Zr so formed can be beneficial by gettering impurities such as oxygen, nitrogen, and carbon, and by altering the overall ZrB.sub.2 stoichiometry, e.g., to ZrB.sub.1.97. Excess Zr is present in the matrix as a finely dispersed material. A variety of dopant materials can also be used to alter the electrical, thermal, and mechanical properties. Samples exhibiting this Zr-rich second phase exhibit lower electrical resistivities, higher thermal conductivities, better thermal shock resistance.