Unit	Al₂O₃(KD960)	Al₂O₃(KD995)	ZrO₂(KD940)
Specific Gravity	g/cc	3.7	3.9	6.1
Hardness Rockwell	HRA	78.0	83.0	80.0
Toughness	MN/m-3/2	2.0	3.0	8.0
Flexural strength	(25℃) kg/㎠	3,100	3,800	13,000
coefficient of thermal expansion	×10-6/℃	8.2	8.3	9.5
Thermal shock	ΔT,℃	200.0	250.0	290.0
Thermal conductivity	w/mk	22.0	23.0	30.0
Working temperature	℃	1,500	1,600	800
Young`s modulus	106kg/㎠	3.3	3.8	2.0

	Unit	Reaction-bonded Sillcon carbide	Pressureless-sintered Sillcon carbide
Density	g/㎤	3.02	3.00
Hardness (knoop)	kg/㎟	1700	2800
Compressive trenght	MPaX103lb/in2	＞3900	＞3900
Flexural strengh 4pt	MPaX103lb/in2	＞350	＞450
Free-si content	%	8~12	＜0.3
purity (SiC Content)	%	＞88	＞99
Modulus of elasticity	GPax1062	4.12×105	4.30×105
Poisson ratio		0.15	0.15
Max service temp air	℃	4.3×10-6	4.3×10-6
Coefficient of thermal expansion RT to 700℃	I/℃	1500	1600

	Unit	Tungsten carbide
Density	g/㎤	15.0
Hardness Rockwell	HRA	92.0
TRS	N/㎟	2,590
Young`s modulus	kg/㎟	62,000
Compressive Strenght	kg/㎟	530.0
Thermal Exp.coeff	x10-6/℃	5.0
Thermal conductivity	cal/cm℃sec	0.19