Alloy Geek Kovar Nickel-Iron-Cobalt Standard
Kovar is a nickel-iron-cobalt alloy known for its low coefficient of thermal expansion (CTE) which closely matches that of borosilicate glass. This property makes it suitable for applications where a strong, hermetic seal is required between metal and glass, especially in electronics and telecommunications industries. Kovar's ability to maintain its dimensions over a range of temperatures helps prevent thermal stress and cracking in these applications.
The composition of Kovar typically includes:
- Nickel (about 29%)
- Cobalt (about 17%)
- Iron (about 54%)
- Trace amounts of other elements like manganese, silicon, carbon, phosphorus, and sulfur
Key features and characteristics of Kovar:
Low Thermal Expansion: Kovar's primary advantage is its low coefficient of thermal expansion, which allows it to match the expansion and contraction of glass and ceramics.
Hermetic Sealing: Kovar's compatibility with glass and ceramics makes it a popular choice for hermetic sealing in electronic and microwave packages, light bulb seals, and other applications where a reliable seal is essential.
Applications: Kovar is used extensively in electronics, including semiconductor packaging, microwave tubes, integrated circuits, and other components requiring a reliable glass-to-metal seal.
Machinability: Kovar is machinable, though its high iron content may lead to work hardening during machining.
Weldability: Kovar can be welded using various methods, but its properties near the weld area may change due to heat input.
Forms: Kovar is available in various forms, including sheets, plates, bars, rods, and wires.
Due to its unique properties, Kovar finds its niche in applications where glass and metal need to be sealed reliably, while maintaining a stable shape under changing temperature conditions. If you're considering using Kovar for a specific project, consulting with materials experts or manufacturers is recommended to ensure its suitability for your intended application.
Reference Material (RM): A reference material, or RM, is a material with a known composition or property that is used for informational purposes to look at analytical instruments, methods, or procedures. It serves as a point of comparison to ensure the accuracy and reliability of measurements. Reference materials can vary in terms of their level of characterization and traceability. Some reference materials may have well-defined properties, but they might not have undergone the rigorous testing and certification process that certified reference materials (CRMs) undergo. Reference Material chemical compositions are for information purposes.
Certified Reference Material (CRM): A certified reference material, or CRM, is a type of reference material that has been thoroughly analyzed and characterized using multiple validated methods to determine its composition or properties. The results of these analyses are then used to establish certified values, along with associated uncertainties. CRMs are produced and certified by accredited organizations or laboratories following internationally recognized standards, such as ISO Guide 34 and ISO/IEC 17025. The certification process includes interlaboratory comparison and statistical analysis to ensure accuracy and traceability.
In summary, the main difference between a reference material and a certified reference material lies in the level of characterization, validation, and certification. CRMs have undergone a more comprehensive and rigorous testing process, resulting in certified values and uncertainties that can be confidently used for instrument calibration, quality control, and research. Reference materials, on the other hand, can provide a point of comparison but might not have the same level of certification and traceability as CRMs. When accuracy and traceability are critical, certified reference materials are preferred.