National
Electronic Alloys Summary of Products
A
Company Dedicated To Customer Service & Quality
|
KOVAR
HEAT TREATMENT
|
| Decarburization is used for reducing carbon,
absorbed gases, and removing surface contaminants.
It is intended as a final cleaning treatment
for part being sealed, plated or brazed. |
|
1. Degrease and chemically
clean.
|
|
2. Heat treat in we hydrogen
or dissociated ammonia.
|
|
3. Firing Temperature
– 900°C to 1100°C.
|
| (Use water bubbler at room temperature)
|
|
950°C
|
15 minutes
|
Semiconductor parts
|
|
1000°C
|
30 minutes
|
Electron tube parts
to be plated or glass sealed.
|
|
1000°C
|
45 minutes
|
Heavy bar or plate
parts
|
|
1050°C
|
20 minutes
|
For parts intended
to be brazed at equivalent temperatures
|
|
Heat
Treatment for Oxidation
|
| 1. Make sure that proper methods are used
to clean, degrease, and bright dip parts. |
2. Oxidation – Heat treat in an electric
air furnace to
850°C to 900°C, until parts are
cherry red (dull red
heat). The length of heat cycle is approximately
3
minutes, but due to differences in humidity
and furnaces, the
proper cycle has to be varied. Then reduce
heat approximately
10 degrees °C per minute. When parts
are cooled, oxide will be
formed. The Black is normally considered
to be over oxidation
and is not necessarily desirable for a good
glass to metal seal. |
|
KOVAR
MAGNETIC PROPERTIES
|
| Material will be magnetic at all temperatures
below the Curie Point. Magnetic Properties
depend upon Heat Treatment. The softer the
material, the higher the Permeability Values
and lower Hysteresis Loss. Examples of Permeability
are as follows… |
|
Flux Density
|
Permeability (Treatment
1830°F(999°C)30min-FC)
|
Permeability (Treatment
2010°F(1099°C)20min-FC
|
|
5000
|
1000
|
1900
|
|
1000
|
1400
|
3500
|
|
2000
|
2000
|
5800
|
|
5000
|
2300
|
10000
|
|
10000
|
3400
|
8200
|
|
12000
|
3000
|
5000
|
|
Flux
Density: Magnetic, Electric or Radiant
Flux per unit area normal to the direction
of the flux.
|
| Density |
.302 lb/in |
| Specific Gravity |
8.36 |
| Curie Temperature |
815°F (435°C) |
| Melting Point |
2640°F (1450°C) |
| Specific Heat |
0°C .105 Cal/gm/°C
430°C .155 |
| Heat of Fusion |
64 cal/gm |
| Thermal Conductivity |
120 BTU-in/sq.ft/hr/°F@77°F
17.3 W/meter x K |
| Electrical Resistivity |
294 Ohm/cir.mil.ft
490 micro ohm – mm |
| Kink Point |
806°F |
| Shear Modulus |
7.5 x 10 |
| Young’s Modulus |
20 x 10 |
| Ultimate Tensile Strength |
75,000 psi |
| Yield Strength |
50,000 psi |
|
Elastic Limit
|
Same approx. as Yield |
| Glass Matches |
Corning 7052 or 7050, 7055, 7056, 7062
& others
Kimble EN-1 (Owens Corning)
K650
K704 |
|
|
|
|
|
