BN - Boron Nitride

Thermal properties

Basic parameters

Zinc Blende crystal structure
    Remarks Referens
Bulk modulus 400 GPa    
Debye temperature 1700 K    
Melting point, Tm 2973° C also see Phase diagrams for BN. Wentorf (1957)
Specific heat ~0.6 J g-1°C -1    
Thermal conductivity
    experimentally achieved
    theoretically estimated
7.4 W cm-1 °C -1
~13 W cm-1 °C -1 		   
Thermal expansion, linear
 1.2·10-6 °C -1    
Termal properties for Hexagonal crystal structure
    Remarks Referens
Debye temperature 400 K    
Bulk modulus 36.5 GPa    
Melting point   see Phase diagrams for BN. Solozhenko (1994) and Solozhenko et al.(1998)
Decomposition temperature, Tdec 2600(100) K Janaf Thermochemical Tables (1965)
Specific heat ~0.8 J g-1°C -1    
Thermal conductivity
    parallel to the c axis
    perpendicular to the c axis
 =<0.3 W cm-1 °C -1
=<6 W cm-1 °C -1 		  Rumyantsev et al. (2001)
Thermal expansion, linear
    parallel to the c axis
    perpendicular to the c axis
 38·10-6 °C -1
-2.7·10-6 °C -1 		   

Wurtzite, Zinc Blende & Hexagonal crystal structure at 300 K
Crystal structure Wurtzite Zinc Blende Hexagonal
Bulk modulus 400 GPa 400 GPa 36.5 GPa
Melting point  
see Phase diagrams for BN.
Specific heat ~0.75 J g-1°C -1 ~0.6 J g-1°C -1 ~0.8 J g-1°C -1
Thermal conductivity
    experimentally achieved
    theoretically estimated
  7.4 W cm-1 °C -1
~13 W cm-1 °C -1 		 
    parallel to the c axis
    perpendicular to the c axis
     <0.3 W cm-1 °C -1
<6 W cm-1 °C -1
Thermal expansion, linear
   1.2·10-6 °C -1  
Thermal expansion, linear
    parallel to the c axis
    perpendicular to the c axis
 2.7·10-6 °C -1
2.3·10-6 °C -1 		  38·10-6 °C -1
-2.7·10-6 °C -1

Thermal conductivity

BN, Zinc Blende. Temperature dependence of thermal conductivity for different samples.
Slack (1973), Makedon et al. (1972)
BN, Zinc Blende. Temperature dependences of the thermal conductivity of  undoped and Se doped before and after annealing at 900-1000 K.
1- undoped Zinc blende BN;
2-4 - Se doped Zinc blende BN
Selenium concentration:
  2 -- 2.4 x 1018 cm-3, before annealing;
  3 -- 2.4 x 1018 cm-3, annealed;
  4 -- 1019 cm-3, annealed
Shipilo et al. (1986)

The highest thermal conductivity achieved for single-crystal zinc blende BN is 7.4 W cm-1 K-1 [Novikov et al. (1983)].
BN, Hexagonal. Thermal conductivity perpendicular to the c axis versus temperature of three samples deposited at different temperatures.
Duclaux et al. (1992)
BN, Hexagonal. Thermal conductivity perpendicular to the c axis versus temperature of highly oriented samples.
Sichel et al. (1976)

BN, Hexagonal. Thermal conductivity perpendicular to the c axis as a function of temperature for two samples.
Simpson & Stuckes (1971)

BN, Hexagonal. Thermal conductivity parallel to the c axis as a function of temperature for two samples.
Simpson & Stuckes (1971)

Temperature dependence of the specific heat

Wurtzite BN . Temperature dependence of the specific heat.

BN, Wurtzite. Temperature dependence of the specific heat.
Gorbunov et al. (1988); see also Sirota & Kofman (1976) and Inaba & Yoshiasa (1997).
The abnormality with extremum at 21 K is caused by the presence of the ordered point defects system in the lattice for two samples. Solozhenko (1994)

At 420 K < T < 980 K, the specific heat Cp of Wurtzite BN can be approximated as
Cp= 48.35x (T2 ·(T2- 8.37xT+ 68306)-1)2 (J/Kmol) Solozhenko (1994).

Zinc Blende BN . Temperature dependence of the specific heat.

BN, Zinc Blende. Temperature dependence of the specific heat at low temperatures (single crystal).
Solozhenko et al. (1987); see also Sirota & Kofman (1976).

BN, Zinc Blende. Temperature dependence of high temperature specific heat according to different authors.
Lyusternik and Solozhenko (1992).

At 300 < T < 1100 K, the specific heat Cp of Zinc Blende BN can be approximated as
Cp= 48.4x (T2 · (T2-  9.71xT+ 60590)-1)2 (J/Kmol) Lyusternik and Solozhenko (1992).


Hexagonal BN . Temperature dependence of the specific heat.

BN, Hexagonal. Temperature dependence of specific heat.
Gorbunov et al. (1988); see also Sichel et al. (1976)

At 1300 < T < 2200 K, the specific heat Cp of can be approximated as
Cp= 52.48 - 9.42·10-4 x T - 64877 x T-2 (J/Kmol) Solozhenko (1994).


Linear thermal expansion coefficient.

BN, Wurtzite. Linear thermal expansion coefficient of parallel (curve 1) and perpendicular (curve 2) to c axis.
Kolupayeva et al. (1986).
BN, Hexagonal. Linear thermal expansion coefficient.
Slack & Bartram (1975).
BN, Zinc Blende. Linear thermal expansion coefficient
Top curve, in a direction parallel to the c axis; bottom curve, in a direction perpendicular to the c axis.
Yates et al. (1975). See also Belenkii et al. (1985).

Thermal expansion at different pressure

BN, Hexagonal. Thermal expansion at different pressure:
circles, 1.6 GPa; squares, 5.0 GPa; triangles, 7.1 GPa. Solid and open symbols are used for the directions parallel and perpendicular to c axis, respectively.
Solozhenko & Peun (1997).

Phase diagrams

Phase diagrams for BN.
1, Bundy-Wentorf's diagram; 2, Equilibrium diagram; , h-BN <=> c-BN boundary line.
Solozhenko (1994)
Equilibrium phase diagram of BN.
1 is hexagonal-zinc blende BN liquid triple point; 2 is hexagonal-wurtzite BN liquid metastable triple point;
a) line of hexagonal-wurtzite BN metastable equilibrium; b) metastable beam of hexagonal BN melting curve; c) line of wurtzite BN metastable melting .
Solozhenko et al.(1998)