CHROMIUM

PROPERTY	@ 300K	UNITS	REFERENCES
Density	7.16	G/cm³	Cr1 Cr2 Cr3
Specific Heat	0.1077	Cal/g-K	Cr4 Cr5 Cr6
Thermal Conductivity	0.216	Cal/cm-s-K	Cr7 Cr8 Cr9
Thermal Exp Coef	5.1x10^-6	1/K	Cr10 Cr11 Cr12
Melting Point	2130	K	Cr13
Resistivity 1	13.5x10^-6	Ohm-cm	Cr14 Cr15 Cr16
TCR (218K to 398K)	2300	Ppm/K	Cr14 Cr15 Cr16
Young’s Modulus	4.03x10⁷	psi	Cr17 Cr18 Cr19
Poisson’s Ratio	0.215	-----	Cr17 Cr18 Cr19
Yield Strength 2	------	psi	Cr20 Cr21 Cr22
Ult Tensile strength	20000-40000	psi	Cr20 Cr21 Cr23
Elongation at Break	0	%	Cr20 Cr21 Cr23
Hardness	89	Brinell	Cr24 Cr25 Cr26

1: Deposition of Chromium in 10^-5 to 10^–6 torr onto substrates in the temperature range of 100 to 400C produces films with resistivities in the range 15-90 micro-ohm-cm. [Cr27]

2: Chromium, like most body centered cubic materials, exhibits a dramatic ductile to brittle transition as the temperature is lowered. The transition temperature for Chromium varies from –15C to 450C depending primarily on the interstitial impurity content (300 wppm nitrogen increases transition to 450C) and grain size. In the brittle condition, chromium exhibits intergranular or cleavage fracture with virtually no elongation. In this condition, there is no yield strength.

Mechanical properties are for fully annealed, bulk samples. Wrought material stress relieved at 800C can have tensile strengths to 60,000 psi and elongations (0.5 inch gauge length) of 50%. [Cr28] Heating cold worked material to 1000 to 1100C results in recovery and recrystallization erasing the effects at cold work.

The Neel temperature for Chromium is 311K. The associated magnetic transition has dramatic effects on the physical properties as shown in the accompanying graphs.

Engineering Materials

Revised: April 17, 2004