Thermal expansion of Chromium (Cr) to melting temperature

• Published in: Calphad 1997, Vol.21 (4), p.497-508
• Main Authors: Dubrovinskaia, N.A., Dubrovinsky, L.S., Saxena, S.K., Sundman, B.
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Heat capacities of solids; LIQUID; Metals. Metallurgy; Physics; Thermal expansion; thermomechanical effects and density; Thermal properties of condensed matter; Thermal properties of crystalline solids
• ISSN: 0364-5916; 1873-2984
• DOI: 10.1016/S0364-5916(98)00007-8

In situ x-ray data on molar volumes of chromium have been collected over the temperature range from 300 K to melting. The sample was heated to melting by passing an electrical current through the sample (the technique of electrical resistance wire heating). The sample consists of a tungsten wire as a heater and a mixture of Cr and W powder, which is placed in a hole of 250 μm diameter. Tungsten was used as an internal standard for temperature determination. In order to prevent the specimen from oxidation, the experiments were carried out in an argon flow. Unit cell parameters of Cr at different temperatures were calculated using (110), (200), (211), and (220) reflections. Precision of determination of lattice parameter is 10 −4 A at 300 K and 5 10 −4 A at 2000 K. Thermal expansion of Cr increases rapidly at temperatures higher than 1200 K. The linear thermal expansion (α) of chromium between 300 and 2130 K is given by: α = 1.220(5) 10 −5 − 1.150(6) 10 −8 T + 1.132(8) 10 −6 T 2 − 0.507(7)/T 2 (T, K). In our experiments, Cr melted between 2120 and 2150 K.