The ultimate corrosion resistance is the most fundamental feature of tantalum wire. It has unparalleled resistance to the vast majority of inorganic acids (such as aqua regia, hydrochloric acid, nitric acid, sulfuric acid), liquid metals and chemical media. Its stability in corrosive environments far exceeds that of stainless steel, nickel-based alloys and other excellent high-temperature properties. Its extremely high melting point (~3017°C) enables it to maintain its shape and strength at high temperatures. It can operate stably for a long time at temperatures above 2000°C in a vacuum or inert atmosphere. It has excellent biocompatibility, is completely inert to human tissues, is non-toxic, non-allergenic, and has no rejection reaction. It can coexist safely with human tissues for a long time and meets the highest standards of implant materials. Unique surface characteristics.
A very dense, stable and insulating tantalum pentoxide (Ta2O5) oxide film can spontaneously form on the surface. This film is the basis for its corrosion resistance and as a capacitor dielectric. It has excellent comprehensive mechanical properties, with a balance between strength and flexibility. Pure tantalum wire is very soft in the annealed state and can be easily bent, wound and woven. The strength is significantly enhanced after work hardening.
Wire materials with an extremely wide diameter range can be produced through precise drawing processes, from the micrometer level to several millimeters level (such as φ3mm for heating elements), and the requirements for dimensional accuracy and surface finish control are extremely high. The surface conditions are diverse: it can present a bright (polished), a dark (alkali washed) finish, or obtain decorative surfaces such as blue and colored ones through anodizing. Optional states: Annealed state (soft state) is provided to facilitate subsequent molding, or hard state to achieve higher strength. Welding should be carried out under the protection of high-purity inert gases (such as argon) or in a vacuum (commonly electron beam welding and laser welding) to prevent oxidation contamination.
As the anode guide pins of tantalum capacitors, the anode leads of capacitors need to maintain exactly the same physical and chemical behavior as the tantalum powder sintered body during strict processes such as enabling (forming an oxide film), impregnating with acid solution, and welding. Any slight corrosion or thermal expansion mismatch will lead to failure. This is its largest and most unique application. As the heating element or support suspension wire of vacuum high-temperature furnaces, it has low volatility at high temperatures and does not contaminate the heated materials (such as monocrystalline silicon and sapphire). It is an important choice other than tungsten and molybdenum wires, especially in situations where better thermal shock resistance and ductility are required. As surgical sutures, bone repair nets, orthodontic wires, etc., in addition to having good biocompatibility, their property of not transmitting X-rays facilitates postoperative imaging localization and observation.
Pure tantalum has excellent plasticity at room temperature and can be processed into extremely fine specifications through multiple cold drawing passes. During the processing, no complex high-temperature heating is required. Only intermediate vacuum annealing (1000-1200℃) is needed to eliminate work hardening. It can undergo secondary processing such as winding, bending and welding, and is not prone to cracking. It is suitable for making leads for precision electronic components and suture threads for medical implants, etc. It is non-toxic and non-allergenic, has excellent compatibility with human tissues and body fluids, will not cause immune rejection reactions, and the surface oxide film can promote the growth of bone cells (biological activity). It can be implanted in the human body for a long time, such as as a fixation wire for orthopedics, a suture wire for nerves/tendons, a support wire for vascular stents, etc. Its application in the medical field is irreplaceable.
The characteristics of tantalum wire can be summarized as a special high-performance metal wire material that integrates "extreme corrosion resistance, outstanding high-temperature stability, and perfect biocompatibility". It holds an irreplaceable core position in the field of electronic capacitors and plays a key role in markets such as high-temperature vacuum, high-end medical care, and extreme anti-corrosion. However, its sensitivity to hydrogen embrittlement, tendency towards high-temperature oxidation, and high cost are the constraints that must be strictly considered in its design, material selection, and application. Ultra-high purity tantalum wire (purity ≥99.99%) or tantalum wire with added trace alloying elements (such as N, C) is not prone to embrittlement in high-temperature oxidation environments, has a high elongation retention rate, and is suitable for components that are used for a long time in high-temperature air (such as high-temperature sensor probes).
