CeramVar / UNS K94100 (Modified) / 1.3981 (Modified) / Ni33Co12

📄 Product Description: CeramVar / 33NK — Precision Alloys with Controlled Thermal Expansion

🧾 General Technical Characteristics

CeramVar (international designation Fe–Ni27–Co25) is a high-tech precision alloy with exceptional thermal stability and a low coefficient of thermal linear expansion (CTE). CeramVar sheets and plates are available in thicknesses from 0.10 mm to 40 mm, with widths up to 500 mm.

33NK is the domestic equivalent of CeramVar, classified as a precision alloy with a specified CTE. It is used for sealing glass-to-metal and ceramic-to-metal joints in a temperature range from –70 to +450 °C.

⚙️ Applications

• CeramVar (4J33/4J34) is widely used in vacuum electronics, for the production of glass-to-metal and ceramic-to-metal seals, flat lenses, infrared optics, and temperature-sensitive components.
• 33NK is used for soldering with soft glass (type C72‑4), sealing ceramics and mica in vacuum devices where a stable CTE of 6–9×10⁻⁶ 1/°C is required in the range of –70 to +450 °C.

📈 Key Advantages

• ✅ Low and stable CTE (6–9×10⁻⁶ 1/°C) — ideal for optical and vacuum systems.
• ✅ Excellent thermal and corrosion resistance, suitable for aggressive environments.
• ✅ Wide supply range — sheets, plates, wire, rods, tubes, capillaries.
• ✅ Suitable for deep stamping (hardness up to 170 HV).

🧪 Chemical Composition

CeramVar / 4J33 (equivalent to 33NK):

• C ≤ 0.05 %
• S, P ≤ 0.020 %
• Si ≤ 0.30 %
• Mn ≤ 0.50 %
• Ni 32.1–33.6 %
• Co 14.0–15.2 %

33NK:

• Fe 48.2–51 %, C ≤ 0.05 %, Si ≤ 0.3 %, Mn ≤ 0.4 %, Ni 32.5–33.5 %, Co 16.5–17.5 %, S, P ≤ 0.015 %

🧩 Mechanical and Physical Properties

• Tensile Strength (Rₘ):
  • CeramVar (annealed): < 570 MPa; (non-annealed): > 700 MPa
  • 33NK (cold-rolled strip): ~930 MPa
• Hardness for deep stamping:
  • thickness >2.5 mm → <170 HV; <2.5 mm → <165 HV
• Coefficient of thermal expansion (20–500 °C):
  • ~6.0–7.4×10⁻⁶ 1/°C (CeramVar / 33NK)
• Density: ~8.2 g/cm³

✅ Conclusion

CeramVar (4J33/4J34) and its domestic counterpart 33NK are premium alloys with low CTE, high mechanical strength, and excellent resistance to high temperatures and aggressive environments. Perfect for:

• glass-to-metal / ceramic-to-metal sealing
• vacuum electronics
• optical and high-sensitivity instruments

Delivery Forms CeramVar / 33НК