An analysis of electrical resistivity of compositions within the Mo–Si–B ternary system part II: Multi-phase composites

The temperature dependence of electrical resistivity between 25 and 1500°C was determined for several multiphase composites within the Mo–Si–B system. The electrical behavior of these composites is determined by that of the single phase components and can be characterized as representative of semimetallic behavior. A predictive model for the resistivity of composites based on the properties of the single phase benchmark compounds was developed based on a logarithmic rule-of-mixture relationship. Error values for the model were calculated based on experimental error in the determination of volume fraction, porosity, and resistivity of each phase as a function of temperature. Experimental resistivity values for multiphase compositions within the Mo5Si3–MoSi2, Mo5Si3Bx (T1)–MoB–MoSi2, and Mo5Si3Bx–Mo5SiB2 (T2)–Mo3Si phase fields are shown to be in good agreement with the model to within one standard deviation.