Nilo 42 Alloy (UNS K94100)

Nickel and Iron-Nickel (Fe-Ni) alloys are actually commercial semiconductor materials, the lead frames of alloy 42 are used on the wide scale for high consistency ceramic Cer-DIP and plastic packaged equipments that need these benefits:

1. Globally available – Invar 42 or alloy 42 is made in semiconductor equipments in the all parts of world.
2. Fundamentally greater strength and firmness- Very high mechanical strength such as yield strength and elastic modulus of invar 42 are essential in decreasing the deformation of leads particularly in automatic insertion.
3. Elevated melting and stress relaxation temperature limits – strength and firmness are fully sustained while exposure to soldering, burning and other production procedures where the alloy is subjected to the elevated temperatures.
4. Greater hardness at temper – It is reflected in enhanced lead frame strip surface
5. No intermetallic compounds can be deleterious to solderability – large mechanical strength is produced while cold processing.
6. Higher bending features at the temper for lead frames – essential in producing perpendicular and J-bent structures.
7. Similar thermal expansion to alumina, beryllia and vitreous glass – essential in preventing fractures and cracks in soldered joints
8. Plateabiltiy- Invar 42 strip is platted, stripped or spot platted using nickel, copper or lead-tin solder or gold or silver.
9. Welding – Nilo alloys are easily welded by spot, projection, seam, stitch, flash and various resistance fusion procedures. Invar 42 is also suitable for ultrasonic and thermocompression bonding and electron-beam and laser welding.
10. Cladding – A strip is fabricated by cladding or inserting 42 alloy with copper, aluminum, gold, silver to receive the outstanding characteristics of double or many alloys or metals and to decrease cost.

These properties enhance the application level of Invar 42 where heat resistance, moisture or vigorous corrosion resistance is required in addition of prolong life with high stability.

Heat management in semiconductor equipments and printed circuit board parts

Controlling junction and die temperature limits in microelectronic equipments and parts need attention to chip and board design, part densities and quenching devices. Such design factors and huge thermal conductance of the ceramic or epoxy package often have more influence than the thermal conductivity of the lead frame material.

The thermal test boards and systems are commonly employed to test a new system and board designs and these must be utilized to find the variation between the thermal conductivity of Invar 42 lead frame and copper metal frame.

The high consistency and excellent mechanical characteristics of invar 42 should be considered due to the thermal conductivity of the alloy that is not much high as of copper alloys.

Property

 Invar 52 (UNS N14052)

Invar 52 or 52 alloy (ASTM F30) have thermal expansion properties similar to viterous potash soda lead glass. Its rate of thermal expansion is constant up to 565oC or 1050oF. An enhanced 52 alloy with larger nickel percentage (51 to 51.5%) attains the combination of limited expansion and magnetic characteristics needed for mercury wetted reed switches.

Nickel alloys are usually used in electronic applications in combination with non-metallic materials in sealing, mounting and packing.

Invar 36 (UNS K93600)

Invar alloys offer the minimum thermal expansion among all metals and alloys in the temperature limit of ambient to 230oC or 446of. The characteristics are shown in the following table. The super- Invar alloy has almost zero expansion at this limit. The common applications of Invar are:

1. Controlled expansion side of thermostatic bimetals
2. Precision gauging equipments and gauges
3. Clamps and fixtures that offer great configuration stability
4. Radar resonant cavities
5. Containers and pipes for liquefied gas
6. Special joints and washers

Properties

 Nickel 200,201

The commercially pure nickel alloys received in the several grades, with nominally different compositional changes are significant for special applications. These grades typically have high strength, ductility and corrosion resistance over a broad temperature limit.

The common applications of wrought nickel are semiconductor packing cans, high temperature electrical wires, magnetostrictive equipments, battery plaques, electrode tube cathodes and anodes etc. Nickel metal is easily deep drawn, spun, coined, etched, welded and brazed.

Nickel has great magnetic properties at the ambient temperatures. Analysis shows that magnetic characteristics of completely pure nickel foils and bulk nickel are identical. The curie temperature for nickel is influenced by earlier heat and mechanical processing and the nature and magnitude of contaminants. The alloying agents usually decrease its curie temperature.

The essential saturation induction value of Nickel 200 is 6000G and in high purity nickel is 6200G.

The initial permeability of nickel 200 is 200 and the highest permeability is 1000H. The coercivity of nickel is 0.7 to 2.7 Oe, widely influenced by forming and heat processing.

Nickel offers one of the widest magnetostrictive effects among commercial materials and is widely used in equipments whrere needed.

 Stainless steel AISI 304

SS 304 is a commonly used 18Cr-8Ni stainless steel that is work hardenable to high strength levels and with outstanding corrosion resistance, weldablity and formability. The great spring characteristics produced at the ambient and high temperatures lead to its application in non-current carrying springs of various sizes. The corrosion resistance and fabricability of AISI 304 lead to several applications as structural parts and security covers for system assemblies where strength, hardness, durability and security from aggressive and corrosive conditions are essential. The composite stainless strip using precious metal cladding, inlay or plating makes it feasible to receive structural and spring attributes of stainless steel with the contact properties of highly conductive metal strip at a budgetary price.

Stainless steel 304/304l is the most commonly used stainless steel grade with potential to withstand atmospheric corrosion, is resistant to food processing conditions, organic chemicals, dyestuffs and ments, and a range of inorganic chemicals. It is also resistant to several oxidizing acids such as nitric acid, cold concentrated sulfuric acid, peracetic acid etc. It can be utilized in electronic packing or as structural or shielding material for electronic or electrical parts and equipments that need high reliability and security from vigorous corrosive media.

Stainless steel 304l is utilized to replace the ordinary carbon grade that is sensitive to welding or hot forming while fabrication.