What Is Metal Fiber?
Metal fiber, characterized by its thin, fibrous form, is manufactured in diameters ranging from less than 10 µm to around 200 µm. Production methods include pultrusion, melt spinning, cutting, and recently developed techniques such as chemical vapor deposition (CVD).
Historically utilized for their decorative qualities, gold and silver threads have evolved into a focus on composite materials development, producing fibers from materials like stainless steel, aluminum, iron, nickel, copper, tungsten, molybdenum, and beryllium.
Uses of Metal Fiber
Employed in specialized areas such as composites, reinforcement, filtration, and static elimination, metal fibers like stainless steel are incorporated into fabrics for antistatic purposes. Decoratively, gold and silver retain their traditional roles, while iron in cotton form is used for polishing. Metal fibers enhance the durability and rust resistance of various filters and, due to their conductive nature, serve as electromagnetic wave shields.
Despite their utility, metal fibers’ hardness and potential for skin irritation limit their use in clothing, though they find application in bra cup shaping materials and wires.
Principles of Metal Fiber
1. Drawing Method
The pultrusion method involves stretching metal wire through dies of progressively smaller sizes to form thin metal fibers.
2. Melt-Spinning Method
Metal is melted and extruded through nozzles to produce fibers in the melt-spinning method.
3. Cutting Method
A thin metal sheet is wound around the spindle of a cutting machine, where it is cut into fibers.
Types of Metal Fiber
Metal fibers vary in form, including “tow” (bundles of fibers), “web” (cotton-like), “needlepunched web” (processed into sheets), and “sintered product” (porous materials made by sintering). Sintered products, known for their permeability and resistance to heat and corrosion, alongside other forms like nonwovens and felts, can be converted into yarn for reinforcing composite materials.
How to Select Metal Fiber
Chosen for their electrical and thermal conductivity, tenacity, and resistance to heat, metal fibers are ideal for industrial uses. However, their hardness and susceptibility to metal fatigue when bent repeatedly make them less suitable for direct skin contact applications.
Structure of Metal Fiber
The focused wire drawing technique, a common manufacturing method, involves pulling bundled filaments through a mold to form composite wire, and then dissolving the tubing to yield long fibers. This process produces fibers with minimal thickness variation and enables the production of ultrafine fibers under 200 nm.