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Ohmalloy 4J29 Kovar Rim Low Expansion Alloys Kovar Thermal Expansion

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Ohmalloy 4J29 Kovar Rim Low Expansion Alloys Kovar Thermal Expansion

Ohmalloy 4J29 Kovar Rim Low Expansion Alloys Kovar Thermal Expansion
Ohmalloy 4J29 Kovar Rim Low Expansion Alloys Kovar Thermal Expansion Ohmalloy 4J29 Kovar Rim Low Expansion Alloys Kovar Thermal Expansion

Large Image :  Ohmalloy 4J29 Kovar Rim Low Expansion Alloys Kovar Thermal Expansion Get Best Price

Product Details:
Place of Origin: Shanghai,China
Brand Name: Ohmalloy
Certification: ISO,SGS
Model Number: 4J29 Kovar alloy
Payment & Shipping Terms:
Minimum Order Quantity: 10kg
Price: USD23/kg
Packaging Details: Wooden case
Delivery Time: 7-20Days after your deposit recieved
Payment Terms: MoneyGram, , L/C, D/A, D/P, T/T
Supply Ability: 5000kg/month
Detailed Product Description
Material: 4J29 Kovar Alloy Type: Strip
Surface: Bright&Mirror Delivery Time: 7-20 Days
Sample: Free Sample Application: Product Casing Frame
Thickness: 0.3mm
High Light:

invar alloy

,

kovar alloy

 
Ohmalloy4J29 Kovar rim for electronic product manufacture,kovar thermal expansion
 
kovar datasheet
OhmAlloy-4J29 (Expansion alloy)
(Common Name: Kovar, Nilo K, KV-1, Dilver Po, Vacon 12)
OhmAlloy-4J29 also known as Kovar alloy. it was invented to meet the need for a reliable glass-to-metal seal, which is required in electronic devices such as light bulbs, vacuum tubes, cathode ray tubes, and in vacuum systems in chemistry and other scientific research. Most metals cannot seal to glass because their coefficient of thermal expansion is not the same as glass, so as the joint cools after fabrication the stresses due to the differential expansion rates of the glass and metal cause the joint to crack.
KOVAR STRIP DETAILS:https://www.youtube.com/watch?v=rUOQtkjdYlo

kovar properties

Kovar is a nickel–cobalt ferrous alloy compositionally identical to Fernico, designed to be compatible with the thermal expansion characteristics of borosilicate glass (~5 × 10−6 /K between 30 and 200 °C, to ~10 × 10−6 /K at 800 °C) in order to allow direct mechanical connections over a range of temperatures. It finds application in electroplated conductors entering glass envelopes of electronic parts such as vacuum tubes (valves), X-ray and microwave tubes and some lightbulbs.
The name Kovar is often used as a general term for Fe–Ni alloys with these particular thermal expansion properties. Note the related particular Fe–Ni alloy Invar which exhibits minimum thermal expansion.
 
OhmAlloy-4J29was invented to meet the need for a reliable glass-to-metal seal, which is required in electronic devices such as light bulbs, vacuum tubes, cathode ray tubes, and in vacuum systems in chemistry and other scientific research. Most metals cannot seal to glass because their coefficient of thermal expansion is not the same as glass, so as the joint cools after fabrication the stresses due to the differential expansion rates of the glass and metal cause the joint to crack.
 
OhmAlloy-4J29 not only has thermal expansion similar to glass, but its nonlinear thermal expansion curve can often be made to match a glass, thus allowing the joint to tolerate a wide temperature range. Chemically, it bonds to glass via the intermediate oxide layer of nickel oxide and cobalt oxide; the proportion of iron oxide is low due to its reduction with cobalt. The bond strength is highly dependent on the oxide layer thickness and character. The presence of cobalt makes the oxide layer easier to melt and dissolve in the molten glass. A grey, grey-blue or grey-brown color indicates a good seal. A metallic color indicates lack of oxide, while black color indicates overly oxidized metal, in both cases leading to a weak joint.
 
Mainly used in electric vacuum components and emission control, shock tube, igniting tube, glass magnetron, transistors, seal plug, relay, integrated circuits lead, chassis, brackets and other housing sealing.
 

 

Normal chemical composition of kovar(%)

Ni28.5~29.5FeBal.Co16.8~17.8Si≤0.3
Mo≤0.2Cu≤0.2Cr≤0.2Mn≤0.5
C≤0.03P≤0.02S≤0.02  

 

Tensile Strength, MPa

Code of conditionConditionWireStrip
RSoft≤585≤570
1/4I1/4 Hard585~725520~630
1/2I1/2 Hard655~795590~700
3/4I3/4 Hard725~860600~770
IHard≥850≥700

 

Typical Physical properties

Density (g/cm3)8.2
Electrical resistivity at 20℃(Ωmm2/m)0.48
Temperature factor of resistivity(20℃~100℃)X10-5/℃3.7~3.9
Curie point Tc/ ℃430
Elastic Modulus, E/ Gpa138

 
 
 
 
 
 
Coefficient of expansion

θ/℃α1/10-6-1θ/℃α1/10-6-1
20~607.820~5006.2
20~1006.420~5507.1
20~2005.920~6007.8
20~3005.320~7009.2
20~4005.120~80010.2
20~4505.320~90011.4

 
 
Thermal conductivity

θ/℃100200300400500
λ/ W/(m*℃)20.621.522.723.725.4

 

The heat treatment process
Annealing for stress reliefHeated to 470~540℃ and hold 1~2 h. Cold down
annealingIn vacuum heated to 750~900℃
Holding time14 min~1h.
Cooling rateNo more than 10 ℃/min cooled to 200 ℃

 
Style of supply

Alloys NameTypeDimension
OhmAlloy-4J29WireD= 0.1~8mm
OhmAlloy-4J29StripW= 5~250mmT= 0.1mm
OhmAlloy-4J29FoilW= 10~100mmT= 0.01~0.1
OhmAlloy-4J29BarDia= 8~100mmL= 50~1000

 

Contact Details
Ohmalloy Material Co.,Ltd

Contact Person: Mr. Qiu

Tel: +8613795230939

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