Density of Ni-Cr Alloy in Liquid and Solid-Liquid Coexistence States

Abstract

A modified sessile drop method was developed to obtain the precise density values for liquid nickel and nickel-chromium alloy in liquid and solid-liquid coexistence states. The density of liquid nickel decreases linearly with increasing temperature in the range from the melting point to 1923 K. The density at the melting point and the thermal expansion coefficient of liquid nickel are 7.91 Mg·m −3 and 1.81 × 10 −4 K −1 , respectively. The density of nickel-chromium alloy in liquid or solid-liquid coexistence state decreases linearly with increasing the temperature and chromium concentration in the alloy. The temperature coefficient of density of nickel-chromium alloy changes at the liquidus temperature. The absolute value of the temperature coefficient of density in solid-liquid coexistence state is larger than that in liquid state.

Measurement of the Density of Ni-Cr Alloy by a Modified Pycnometric Method

“…Experimental result indicates that the mass loss of the sample in the method is smaller than that in the modified sessile drop method, reported by Mukai and Xiao, 19) as AE0:06%. The reason is that the surface of sample exposured to gas in the pycnometer (%28 mm 2 ) is much smaller than that in the modified sessile drop method (%154 mm 2 ).…”

“…2 together with that for the modified sessile drop method. 19) The maximum difference of the thermal expansion resulting from the measurements obtained in heating and cooling cycle is AE1:91%. Thus the maximum measurement error of density arising from thermal expansion in the present work is calculated to be AE0:06% which is larger than that of the modified sessile drop method, AE0:04%, reported by Mukai and Xiao.…”

“…Thus the maximum measurement error of density arising from thermal expansion in the present work is calculated to be AE0:06% which is larger than that of the modified sessile drop method, AE0:04%, reported by Mukai and Xiao. 19) 3.1.5 Errors arising from the temperature distribution in the temperature zone of furnace tube ðd=Þ T The temperature difference ÁT in the temperature zone in which pycnometer is located is AE5 K. The density error arisen from the temperature distribution in furnace tube can be expressed by the following equation:…”

“…19) Using Steinberg's formula, 22) the density data for liquid nickel can be represented by the following equation:…”

“…19) In order to decrease the measurement error further and to obtain more accurate density for liquid nickel and Ni-Cr alloys in the liquid and solid-liquid coexistence states, the authors modified the traditional pycnometric method and applied it to the density measurement of the same Ni-Cr alloy. In order to minimize the influence of the systematic errors of the two methods on the measured value of density, the recommended quation was obtained by regressing the density data measured by the modified sessile drop method and the modified pycnometric method.…”