Alloy 475,Nilo 475 ,UNS K95000,E FORU

British Specs:，American Specs:AMS 7718 Bar, Tube and Forgings MIL-N-14411 Comp 3，German Specs:

### **Alloy 475 (Nilo 475) - Product Overview** **Alloy 475**, commercially known as **Nilo 475**, is a nickel-iron controlled expansion alloy specifically designed for matched sealing with special hard glasses and certain ceramic materials. This alloy offers unique thermal expansion characteristics that bridge the gap between conventional glass sealing alloys and high-performance applications. * **UNS Designation:** **K95000** * **Common Names:** Nilo 475, Glass Sealing 475, 475 Alloy --- #### **1. Chemical Composition** The chemical composition is carefully balanced to achieve specific thermal expansion properties for specialized sealing applications. | Element | Percentage (%) | Role in the Alloy | |:---|:---|:---| | **Nickel (Ni)** | 46.0 - 48.0 | Primary element controlling CTE characteristics | | **Cobalt (Co)** | 24.0 - 26.0 | Modifies thermal expansion and Curie point | | **Iron (Fe)** | Balance | Base structural element | | **Manganese (Mn)** | 0.10 - 0.30 | Enhances workability and acts as deoxidizer | | **Silicon (Si)** | 0.10 - 0.30 | Improves glass wetting characteristics | | **Carbon (C)** | 0.05 max | Limited to prevent embrittlement | | **Sulfur (S)** | 0.02 max | Controlled impurity | | **Phosphorus (P)** | 0.02 max | Controlled impurity | --- #### **2. Physical Properties** Specialized physical properties optimized for unique sealing applications. | Property | Value / Condition | Notes | |:---|:---|:---| | **Density** | 8.35 g/cm³ (0.302 lb/in³) | Higher due to cobalt content | | **Melting Point** | ~1445 °C (2635 °F) | | | **Curie Temperature** | ~420 °C (790 °F) | Modified by cobalt addition | | **Thermal Expansion Coefficient (CTE)** | 20-300°C: 7.8-8.5 μm/m·°C
20-400°C: 8.2-9.0 μm/m·°C | Lower CTE for special applications | | **Thermal Conductivity** | 14.5 W/m·K at 20°C | | | **Specific Heat** | 0.45 J/g·°C at 20°C | | | **Electrical Resistivity** | 0.52 μΩ·m at 20°C | | | **Magnetic Properties** | Ferromagnetic below Curie point | | --- #### **3. Mechanical Properties** Typical properties in annealed condition. * **Tensile Strength:** 540-610 MPa (78-88 ksi) * **Yield Strength (0.2% Offset):** 300-370 MPa (44-54 ksi) * **Elongation:** 25-35% in 2 inches * **Modulus of Elasticity:** 158 GPa (22.9 × 10⁶ psi) * **Hardness (Rockwell B):** 75-90 * **Shear Modulus:** 62 GPa (9.0 × 10⁶ psi) --- #### **4. Product Forms & Specific Applications** **Available Forms:** * Sheet & Strip (0.05 mm to 3.0 mm thickness) * Wire (0.1 mm to 6.0 mm diameter) * Rod & Bar (3.0 mm to 150 mm diameter) * Tubing & Pipe * Custom forgings and fabricated components **Primary Applications:** * **Special Hard Glass Sealing:** Matched seals with unique glass compositions * **Ceramic-to-Metal Seals:** Components requiring specific CTE matching with ceramics * **Aerospace Electronics:** Critical components for avionics and satellite systems * **High-Temperature Sensors:** Specialized sensor packaging and housings * **Microwave Components:** Waveguide and resonator applications * **Medical Imaging Equipment:** X-ray tube components and diagnostic equipment * **Power Electronics:** High-reliability packages for specialized power devices * **Scientific Instruments:** Precision instrumentation requiring unique CTE properties --- #### **5. International Standards** Comprehensive international standardization. | Standard Type | Standard Number | Title / Specification | |:---|:---|:---| | **ASTM** | **ASTM F15** | Standard Specification for Iron-Nickel Sealing Alloys | | **UNS** | **K95000** | Unified Numbering System Designation | | **AMS** | AMS 7724 | Aerospace Material Specification | | **IEC** | IEC 60404-8-6 | Metallic Magnetic Materials Specification | | **DIN** | DIN 1745 | Metallic Materials for Glass-to-Metal Seals | | **ISO** | ISO 9711 | Metallic Materials for Glass-to-Metal Seals | --- #### **6. Glass & Ceramic Sealing Performance** **Compatible Materials:** * Special hard glass compositions with lower expansion requirements * Certain alumina and other ceramic materials * Specific technical glass types requiring unique CTE matching **Sealing Characteristics:** * Optimal sealing temperature range: 900-1000°C * Requires controlled atmosphere (hydrogen or vacuum) * Excellent wetting with compatible glasses and ceramics * Minimal interfacial stress during cooling * Superior thermal cycle resistance --- #### **7. Comparison with Other Sealing Alloys** | Property | Alloy 475 | Alloy 52 | Alloy 42 | |:---|:---|:---|:---| | **Nickel Content** | 47% | 52% | 42% | | **Cobalt Content** | 25% | 0% | 0% | | **CTE (20-300°C)** | 7.8-8.5 μm/m·°C | 9.8-10.5 μm/m·°C | 4.5-5.5 μm/m·°C | | **Curie Temperature** | ~420°C | ~500°C | ~360°C | | **Primary Application** | Special Glasses/Ceramics | Hard Glasses | Ceramics | --- #### **8. Manufacturing Considerations** * **Machining:** Good machinability with proper tool geometry and cooling * **Forming:** Good cold working characteristics in annealed condition * **Welding:** Suitable for TIG, resistance, and laser welding methods * **Heat Treatment:** Annealing at 850-900°C in protective atmosphere * **Surface Preparation:** Critical for optimal sealing performance --- **Summary** **Alloy 475 (Nilo 475, UNS K95000)** represents a specialized member of the nickel-iron-cobalt sealing alloy family, specifically optimized for applications requiring unique thermal expansion characteristics. Its carefully controlled thermal expansion properties, enhanced by cobalt addition, combined with excellent mechanical properties and reliable sealing performance, make it the material of choice for demanding applications in aerospace, medical, scientific instrumentation, and specialized industrial sectors. The alloy's ability to maintain hermetic integrity under thermal cycling conditions while matching the expansion of special glasses and certain ceramics ensures long-term reliability in critical sealing applications. Compliance with international standards including **ASTM F15** guarantees consistent material quality and performance across all product forms and manufacturing processes.

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 2521 gallon liquid totes Special package is available on request.