ASTM B393 UNS R04200 R04210 Pure Niobium Sheet

A: A niobium plate is a metal sheet primarily composed of niobium. Its purity typically reaches over 99.95% (e.g., Nb1 and Nb2 grades), with a density of 8.57 g/cm³, a melting point of 2468°C, and a boiling point of 4742°C. Niobium exhibits paramagnetism and good ductility, but increasing impurity content increases its hardness.

A: Aerospace: Used in thermal protection structures, rocket nozzles, and turbine engine components. For example, C-103 niobium alloy (89% niobium) was used in the Apollo lunar module engine.
Nuclear Industry: Due to its low thermal neutron absorption cross-section, it can be used as a structural material for nuclear reactors or as a nuclear fuel packaging material.
Superconducting Materials: Niobium-titanium (NbTi) and niobium-tin (Nb3Sn) alloys are core materials for superconducting magnets in MRI equipment and particle accelerators. ‌
‌Electronic Devices‌: Used in vacuum coating targets, optical modulators, and surface acoustic wave filters.

A: Niobium plate has become a key material in the vacuum industry due to its excellent high-temperature strength, extremely low vapor pressure, good plasticity, and compatibility with a variety of materials. Its application principles revolve around "stability in vacuum environments" and "functional adaptability." Specific scenarios are as follows:
I. Application Principle: Core Characteristics of Niobium Plate in Vacuum Environments
Extremely Low Vapor Pressure
Niobium's vapor pressure at high temperatures (e.g., approximately 10 Pa at 1000°C) is far below the vacuum limit of the vacuum system (typically required to be less than 10 Pa). Evaporation of the material will not contaminate the vacuum environment or cause an increase in system pressure, making it suitable for long-term operation in high vacuum (above 10 Pa) or ultra-high vacuum environments. High-Temperature Structural Stability
Niobium has a melting point of 2468°C and maintains high mechanical strength below 1600°C (tensile strength is approximately 300 MPa at room temperature and 150 MPa at 1000°C). It is also resistant to deformation at high temperatures, making it suitable as a structural material for high-temperature components in vacuum systems.
Good Airtightness and Workability
Niobium plates can be formed into sealed structures through processes such as welding (electron beam welding) and rolling. Surface treatments (such as oxidation and plating) further enhance airtightness and prevent vacuum leaks.
Chemical Inertness
Niobium does not react chemically with common gases (such as N2 and O2, which require high temperatures) or metal vapors in a vacuum environment, making it suitable for use in vacuum chambers or isolation components.
II. Specific Application Scenarios
1. Vacuum Coating Equipment: Evaporation Source and Shielding Components
Principle: Vacuum coating (such as magnetron sputtering and electron beam evaporation) requires heating the target material in a high vacuum environment to cause evaporation. Niobium plates, due to their high-temperature resistance and low vapor pressure, can serve as support structures or shielding for evaporation sources. Specific Applications: In electron beam evaporation, niobium plates are formed into "crucibles" or "channels" to directly hold high-melting-point targets (such as tungsten metal and ceramic oxides). They operate stably under electron beam bombardment (temperatures reaching 1500-2000°C), preventing self-evaporation and contamination of the thin film.
As a "heat shield," Niobium plates are welded into a multi-layer shielding structure around the evaporation source to reflect heat for improved heating efficiency while preventing target vapor from diffusing into other areas of the chamber.
2. High-Energy Physics Vacuum Chambers: Particle Acceleration and Detection Systems
Principle: The vacuum chambers of particle accelerators (such as synchrotron radiation facilities and electron colliders) must maintain an ultra-high vacuum (10⁻⁹ Pa) and withstand the high temperatures generated by particle beam bombardment (locally exceeding 800°C). Niobium plates' high-temperature resistance and low outgassing properties meet these requirements. Specific Applications: Synchrotron Radiation Source "vacuum tubes": Niobium plates are welded into thin-walled tubes (thickness 0.5-2mm). The inner walls are electrolytically polished to reduce surface roughness (Ra < 0.05μm), minimizing interactions between the particle beam and the cavity walls (such as the electron cloud effect) and ensuring stable particle beam transmission.
Detector Vacuum Chambers: In high-energy particle detectors, niobium plates form a sealed cavity, protecting the precision detection components (such as silicon wafers and scintillators) from atmospheric interference. Niobium's low magnetic properties (niobium is a paramagnetic material) also prevent interference with magnetic field measurement accuracy.
3. Vacuum Heat Treatment Furnaces: Heating Elements and Support Components
Principle: Vacuum heat treatment requires heating workpieces (such as metal alloys and precision parts) in an oxygen-free environment. Niobium plates can serve as heating elements or workpiece supports, leveraging their high-temperature conductivity and structural stability. Specific Applications: Heating Elements for High-Temperature Vacuum Furnaces: Niobium sheets are rolled into corrugated or spiral heating elements, heated by current under vacuum (maximum operating temperature 1800°C). Compared to graphite heating elements, niobium offers improved cleanliness (no carbon contamination), making it suitable for precision heat treatment of aerospace parts.
Carrying Trays: Niobium sheets are welded into a grid-like tray for placing workpieces to be processed. They maintain deformation at temperatures exceeding 1200°C and do not diffuse into the workpiece (such as titanium alloys and high-temperature alloys).