Alloy 42,Nilo 42,UNS K94100,E FORU

### **Alloy 42 / Nilo 42 / UNS K94100** **Iron-Nickel Alloy with Controlled Thermal Expansion for Electronic Packaging** --- #### **1. Overview** **Alloy 42**, commercially known as **Nilo 42**, is an iron-nickel alloy specifically designed to exhibit a thermal expansion coefficient that closely matches those of alumina ceramics, certain glasses, and semiconductor materials like silicon and gallium arsenide. This precise thermal expansion matching makes it indispensable in electronic packaging applications where reliable ceramic-to-metal seals are required. The alloy maintains consistent dimensional stability across a wide temperature range, preventing thermal stress-induced failures in critical electronic components. --- #### **2. Chemical Composition (Weight %)** The typical chemical composition of Alloy 42 is outlined below. The balance is Iron (Fe). | Element | Content (%) | Key Function | | :--- | :--- | :--- | | **Iron (Fe)** | Balance | Forms the primary matrix of the alloy. | | **Nickel (Ni)** | 41.0 - 42.5 | Primary element controlling thermal expansion to match ceramic and glass materials. | | **Manganese (Mn)** | 0.50 - 0.80 | Enhances hot workability and acts as a deoxidizer during manufacturing. | | **Silicon (Si)** | 0.15 - 0.30 | Improves fluidity during processing and enhances oxidation resistance. | | **Carbon (C)** | 0.03 max | Minimized to prevent gas formation and maintain sealing integrity. | | **Chromium (Cr)** | 0.15 max | Controlled impurity. | | **Cobalt (Co)** | 0.15 max | Controlled impurity. | | **Copper (Cu)** | 0.15 max | Controlled impurity. | | **Aluminum (Al)** | 0.05 max | Controlled to ensure proper surface characteristics for sealing. | | **Molybdenum (Mo)** | 0.05 max | Controlled impurity. | | **Sulfur (S)** | 0.015 max | Kept low to prevent hot shortness during processing. | | **Phosphorus (P)** | 0.015 max | Minimized to maintain ductility and workability. | --- #### **3. Physical Properties** | Property | Value / Condition | | :--- | :--- | | **Density** | 8.11 g/cm³ (0.293 lb/in³) | | **Melting Point** | ~ 1420 °C (2588 °F) | | **Mean Coefficient of Thermal Expansion** | 20 - 300°C (68 - 572°F): **4.5 x 10⁻⁶/°C** (2.5 x 10⁻⁶/°F)
20 - 400°C (68 - 752°F): **6.0 x 10⁻⁶/°C** (3.3 x 10⁻⁶/°F)
20 - 450°C (68 - 842°F): **6.8 x 10⁻⁶/°C** (3.8 x 10⁻⁶/°F) | | **Thermal Conductivity** | 14.5 W/m·K (100 Btu·in/hr·ft²·°F) at 20°C (68°F) | | **Specific Heat Capacity** | 515 J/kg·K (0.123 Btu/lb·°F) at 20°C (68°F) | | **Electrical Resistivity** | 0.68 μΩ·m at 20°C (68°F) | | **Modulus of Elasticity (Young's Modulus)** | 145 GPa (21.0 x 10⁶ psi) at 20°C (68°F) | | **Curie Temperature** | ~ 360 °C (680 °F) | | **Magnetic Properties** | Ferromagnetic below Curie temperature | --- #### **4. Mechanical Properties (Typical for Annealed Condition)** | Property | Value at Room Temperature | | :--- | :--- | | **Tensile Strength** | 520 MPa (75 ksi) | | **Yield Strength (0.2% Offset)** | 350 MPa (51 ksi) | | **Elongation (in 50 mm / 2 in)** | 30% | | **Reduction of Area** | 65% | | **Hardness (Rockwell B)** | 78 HRB | | **Vickers Hardness** | 160 HV | --- #### **5. International Standards** Alloy 42 conforms to the following international specifications: * **ASTM:** * **F30:** Standard Specification for Iron-Nickel Sealing Alloys * **AMS:** * **AMS 7721:** Sheet, Strip, and Plate * **UNS:** K94100 * **ISO:** * **ISO 19960:** Iron-nickel low expansion alloys * **JIS:** * **JIS C 2531:** Iron-nickel alloy for sealing use * **IEC:** * **IEC 60068:** Environmental testing (for sealed components) --- #### **6. Product Applications** Alloy 42 is critical in electronic applications requiring precise thermal expansion matching: * **Semiconductor Packaging:** * Ceramic chip carriers * Lead frames for integrated circuits * Transistor and diode packages * Power device housings * **Electronics & Telecommunications:** * Hybrid circuit substrates * Microwave package components * RF and microwave device packages * Connector and feedthrough assemblies * **Aerospace & Defense:** * Hermetic electronic enclosures * Avionics control modules * Military communication devices * Satellite electronic systems * **Automotive Electronics:** * Engine control units * Sensor packaging * Power electronic modules * Under-hood electronic systems * **Consumer Electronics:** * LED packaging * Power supply components * Display driver packages --- #### **7. Key Characteristics & Advantages** * **Precision Thermal Expansion Matching:** CTE of 4.5-6.8 x 10⁻⁶/°C closely matches alumina ceramics (∼7.0 x 10⁻⁶/°C) * **Excellent Sealing Characteristics:** Forms reliable hermetic seals with ceramics and glasses * **Good Mechanical Strength:** Provides structural integrity for electronic packages * **Superior Thermal Stability:** Maintains properties across wide temperature ranges * **Good Electrical Conductivity:** Suitable for lead frame and connector applications * **Excellent Fabricability:** Can be easily stamped, etched, and formed into complex shapes * **Cost-Effective Performance:** Provides reliable thermal matching at reasonable cost * **Proven Reliability:** Extensive history of successful use in critical electronic applications --- **Disclaimer:** *Nilo® is a registered trademark. The values provided are typical and for informational purposes only. For critical applications, always consult the official material data sheets from the supplier and relevant design codes. Proper surface preparation and heat treatment are essential for achieving optimal ceramic-to-metal seals.*

Packing of Standard Packing: Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and steel drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 1685 gallon liquid totes Special package is available on request.