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Brand Name: XANT
Powder Or Not: Not Powder
Grade: Kovar
Application: In power tubes, microwave tubes, transistors,
Type: Nickel Bar

Specifications

Description

Description
Kovar Alloy is a vacuum melted, iron-nickel-cobalt, low expansion alloy whose chemical composition is controlled within narrow limits to assure precise uniform thermal expansion properties. Extensive quality controls are employed in the manufacture of this alloy to ensure uniform physical and mechanical properties for ease in deep drawing, coining, stamping and machining.

Application
Kovar alloy has been used for making hermetic seals with the harder Pyrex glasses and ceramic materials. this alloy has found wide use in application where high reliability is a necessity. In power tubes, microwave tubes, transistors, diodes, inter-grated circuits and has been used for the flat pack and the dual-in-line package.

Product Parameter
Chemical Composition

C P S Mn SI Cu Cr Mo Ni Co Fe
                    ≤
0.03 0.020 0.020 0.50 0.30 0.20 0.20 0.20 28.5-29.5 16.8-17.8 Balance

 
Physical Properties

Specific gravity
8.36
Density
Lb/cu in 0.302
Kg/cu m 8359
Thermal conductivity
Btu-in/ft2/hr/°F 120
W/m-K 17.3
Curie temperature °F 815
°C 435
Melting Point
°F 2640
°C 1450
Modulus of elasticity Psi x 10(6) 20
MPa x 10(3) 138
Electrical resistivity Ohm-cir mil/ft 294
Microhm-mm 490

 
Mechanical Properties

Tensile Strength Ksi
MPa
75
518
Yield Strength Ksi
MPa
40
276
Elongation % in 2 in 30
Typical Hardness Ann Rockwell HRB80
Modulus of Elasticity Mpsi
KMPa
30
207

 
Average Coefficient of Linear Expansion

Heat Treatment of the Samples
 
Average Coefficient of Linear Expansion
20~300C 20~400C 20~450°C
Heat to temperature of  900±20C in the hydrogen, hold for 1h;
Re-heat to 1100±20C, hold for 15 min.; cooled to 200C at a rate
Less than 5C/min

4.6 t o  5.2 5.1 to 5.5

 China Expansion Alloy Hard Glass Sealed Alloy 4j29 Kovar bar