Noncontact Measurements of Thermophysical Properties of Molybdenum at High Temperatures

Four thermophysical properties of both solid and liquid molybdenum, namely, the density, the thermal expansion coefficient, the constant-pressure heat capacity, and the hemispherical total emissivity, are reported. These thermophysical properties were measured over a wide temperature range, including the undercooled state, using an electrostatic levitation furnace developed by the National Space Development Agency of Japan. Over the 2500 to 3000 K temperature span, the density of the liquid can be expressed as rL(T)=9.10×103−0.60(T−Tm) (kg ·m−3), with Tm=2896 K, yielding a volume expansion coefficient aL(T)= 6.6×10−5 (K−1). Similarly, over the 2170 to 2890 K temperature range, the density of the solid can be expressed as rS(T)=9.49×103−0.50(T−Tm), giving a volume expansion coefficient aS(T)=5.3×10−5. The constant pressure heat capacity of the liquid phase could be estimated as CPL(T)=34.2+1.13× 10−3(T−Tm) (J ·mol−1 ·K−1) if the hemispherical total emissivity of the liquid phase remained constant at 0.21 over the temperature iInterval. Over the 2050 to 2890 K temperature span, the hemispherical total emissivity of the solid phase could be expressed as eTS(T)=0.29+9.86×10−5(T−Tm). The latent heat of fusion has also been measured as 33.6 kJ ·mol−1.