Material	Aluminium Oxide		MACOR® Ceramic	Zirconia	Aluminium Silicate Lava		Carbon / Graphite	Boron Nitride
Property Quality Colour	94% White	99,7% White	MACOR® White	≥ 94,4% ZrO2 White / Off-white	Fired Pink	Bisque fired: Pink Unfired: Grey	Grade CS Black	Grade A Off-white	Grade HP Off-white	Grade AX05 Off-white	Grade XSBN Grey
Density / Gravity (g/cm3)	3,6	3,9	2,5	6,01	2,3	2,4	1,75	1,92	1,9	1,91	2,95
Porosity (%)	0	0	0	0	2,3	2,6	23	2,84	15,26	14,2	3,4 / 2,4*
Hardness (MOHS), (Knoop), (GPa), (Rockwell)	9 Mohs	9 Mohs	250 Knoop	12,7 GPa	6 Mohs	2 Mohs	83 Rockwell	15,5 / 24,2* Knoop	13,8 / 18,9* Knoop	3,4 / 4,9* Knoop	95 / 105* Knoop
Compressive strength (MPa)	2300	2600	345	2.400	170	82	46 / 47*	143 / 190*	30 / 44*	18 / 23*	14 / 25*
Max. use temperature (no load) (°C)	1600	1700	1000	1.500	1150	540	3000	850 / 1.800*	850 / 1.800*	850 / 3.000*	850 / 1.800*
Thermal conductivity at room temperature (W/M°C)	20 conductor	26 conductor	1,7 insulator	2,2	1,3 insulator	1,6 insulator	175 / 145* conductor	30 / 34* conductor	27 / 31* conductor	71 / 121* conductor	22 / 40* conductor
Dimensional stability	Excellent	Excellent	Excellent	Excellent	Excellent	Excellent	Good	Excellent	Excellent	Excellent	Excellent
Electrical insulator / conductor	Insulator	Insulator	Insulator	Insulator	Insulator	Insulator	Conductor	Insulator	Insulator	Insulator	Insulator
Thermal shock resistance	Poor	Poor	Poor	Good	Poor	Good	Excellent	Excellent	Excellent	Excellent	Excellent
Corrosion / chemical resistance	Good	Good	Good	Excellent	Good	Poor	Excellent	Excellent	Excellent	Excellent	Excellent
Machinability	Difficult **	Difficult **	Good ***	Difficult **	Difficult **	Good ***	Excellent ***	Excellent ***	Excellent ***	Excellent ***	Difficult **

*wg/ag = with the grain (parallel) / against the grain (perpendiculum)
** only with diamond tools
*** with ordinary or hardened metalworking tools