99% Alumina Ceramic Metallization

Compared to 95% alumina, 99% alumina have high dielectric constant.

Features of this material:

• Exceptionally high dielectric strength
• Consistent dielectric constant
• Dense, non-porous and vacuum tight
• Readily accepts moly-manganese metallizing for high temperature brazing
• Electrically and dimensionally stable across a wide temperature range
• Resist chemical attack and abrasion
• Good thermal conductivity

Metallization :

Moly-Manganese metallizing +Ni plating

Applications:

Medical X-ray tubes
Vacuum feedthrus
Vacuum Interrupter
Ceramic to metal seals
Filaments
Assemblies

Material Properties :

NO	ITEM	Testing condition	Unit	Testing Value	GB/T5593 Specified Value of A-99.5
1	Bulk Density	Room Temp	G/cm³	3.86	≥3.85
2	Flexural Strength	Romm Temp	MPa	368	≥300
3	Average Coefficient of Linear Expansion	(20~500)℃	1/°℃	7.15×10-6	(6.5~7.5)x10-6
		(20~800)℃	1/℃	7.71×10-6	(6.5~8.0)x10-6
4	Dielectric Constant	20℃		10.2	9~10.5
5	Dielectric Loos Angle Tangent Value (Dissipation Factor)	20℃		1.9×10-4	≤2.5×10-4
6	Volume Resistivity	100℃	Ω.cm	4.5×1014	≥1013
		300℃	Ω.cm	2.5×1013	≥1010
		500℃	Ω.cm	4.1x101C	≥10⁸
7	Chemical Stability	1:9HC1	mg/cm²	0.37	≤0.7
		10%NaOH	mg/cm²	0.04	≤0.1
8	Thermal Stability	(Room Temp.~800)℃		PASS	PASS
9	Airtightness		Pa.M³/s	PASS	PASS
10	Dielectric Strength		KV/mm	36.9	≥17
11	Metallization thickness		um	12.7-38.1
12	Plating thickness		um	2.54-10.16