The Molybdenum/Manganese Metallization Breakthrough on Technology of Ceramic to Metal Brazed Used in Vacuum Electronic Devices

• Application: Aerospace, Electronics, Medical, Refractory
• Material Composition: Alumina, Al2O3
• Speciality: High Insulation
• Type: Ceramic Part
• Treatment: Glazed, Polishing
• Color: White+Metal
• Coating Thickness: 8-30μm
• Plated Layer: Nickel/Copper/Gold
• Processing Service: Welding, Moulding
• Plating Thickness: 2-9μm
• Max. Use Temperature: 1600ºC
• Transport Package: Carton Packing
• Specification: Customized
• Trademark: INNOVACERA
• Origin: Fujian, China

Product Description

 

INNOVACERA Alumina Ceramic to Metal Seal Vacuum Feedthrough For High Pressure Brazing

The Molybdenum/Manganese metallization developed the technology on Ceramic-to-metal brazed assembly, it provides high mechanical strength and good electrical insulation. At the very beginning, it's used in vacuum electronic devices, gradually applied to semiconductors, integrated circuits, electric light sources, high-energy physics, aerospace, chemical industry, metallurgy, instrumentation and machinery manufacturing and other industrial fields.

So how to choose a material become more and more critical for a good vacuum brazing. Here we're mainly discussing about 3 different types of materials that will be used for ceramic-to-metal.
 

 

Material	Alumina/BeO/AlN
Coating Layer	Mo/Mn Thickness:8-30μm
Plated Layer	Nickel, Copper, Gold, etc.  Thickness: 2-9μm
Treatment	Glazed, polishing
Dimension	Customized
Joining types
Ceramic + Mo/Mn Metallized + plating Ni
Ceramic + Mo/Mn Metallized + plating Ag
Ceramic + Mo/Mn Metallized + plating Au
Ceramic + printing Ag

 

1. Ceramic
* Al2O3 * BeO * BN * AlN

2. Metala
* Kovar alloy * OFC * Stainless steel

* Mild steel

3. Solder
* Ag * Ag-Cu * Cu * AU-Cu * Au-Ni

 

 

The Ceramic materials are required to be high-temperature stabilized and good thermal expansion of coefficient, INNOVACERA apply mostly the Al2O3. Since ceramics will not be directly wetted, which impedes the adherence of molten metal layers and adhesives, added that the different coefficients of thermal expansion (CTE) between Ceramic and Metal. Breakthrough on such difficulties is with a soldering or brazing process.

 

Metal layer applied on ceramic components via Mo/Mn metallization and Plating or Active brazing, after that, the ceramic and metal components are joined by the melting and subsequent solidification of a filler metal-Solder, with different solders for different applications in different working temperatures.


 

Alumina Ceramic Properties
Properties	Units		Alumina Ceramic
Purity	wt%		95%	99%	99.8%
Volume Density	g/cm3		3.65	3.8	≥3.89
Water Absorption	%		0	0	0
Crystal Size(Grain Size)	μm		4-5	4-5	4-5
Vickers Hardness, HV1.0	Gpa		14	1600	≥15
Flexural Strength	Mpa		300	310	≥300
Coefficient of Linear Expansion	20-500ºC	1x10-6 mm/ºC	6.5-7.5	6.5-7.5	6.5~7.5
	20-800ºC		6.5-8.0	6.5-8.0	6.5~8.0
Thermal Conductivity	W/m·K( 20ºC)		20	25	≥20.9
Specific Heat Capacity	KJ/(kg·K)		≥0.8	≥0.8	≥0.8
Dielectric Strength	KV/mm		≥12	15*106	≥12
Volume Resistivity	Ω·cm 20ºC		≥1014	≥1014	≥1014
	Ω·cm 300ºC		≥1011	≥1011	≥1011
	Ω·cm 500ºC		≥109	≥109	≥109
Dielectric Constant	1MHz		9	9-10	9-10
Tangent of Dielectric Loss	1MHz		≤4x10-4	≤2x10-4	≤3x10-4
Surface Roughness	μm		0.4 After Machine	0.1-0.4 After Machine	0.1-0.4 After Machine
Max Working Temperature	ºC		1600	1600	1650