Sign In | Join Free | My disqueenfrance.com
China Ohmalloy Material Co.,Ltd logo
Ohmalloy Material Co.,Ltd
QUALITY BEST, INTEGRITY FIRST. www.ohmalloy.com
Verified Supplier

8 Years

Home > Low Expansion Alloys >

Ohmalloy 4J29 Kovar Rim Low Expansion Alloys Kovar Thermal Expansion

Ohmalloy Material Co.,Ltd
Trust Seal
Verified Supplier
Credit Check
Supplier Assessment

Ohmalloy 4J29 Kovar Rim Low Expansion Alloys Kovar Thermal Expansion

  • 1
  • 2

Brand Name : Ohmalloy

Model Number : 4J29 Kovar alloy

Certification : ISO,SGS

Place of Origin : Shanghai,China

MOQ : 10kg

Price : USD23/kg

Payment Terms : MoneyGram, , L/C, D/A, D/P, T/T

Supply Ability : 5000kg/month

Delivery Time : 7-20 Days

Packaging Details : Wooden case

Material : 4J29 Kovar alloy

Type : Strip

Surface : Bright&Mirror

Sample : Free Sample

Application : Product Casing Frame

Thickness : 0.3mm

Contact Now


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


























Product Tags:

invar alloy

      

kovar alloy

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

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

Inquiry Cart 0
Send your message to this supplier
 
*From:
*To: Ohmalloy Material Co.,Ltd
*Subject:
*Message:
Characters Remaining: (0/3000)
 
Inquiry Cart 0