The preparation of metal fibers can be performed by drawing method, spinning method, cutting method, grinding method and metal plating sintering method.

1) Drawing method
Ordinary single-wire drawing can obtain extremely fine fibers, and its cross-sectional shape and surface state can reach the best state, the surface is smooth, and the size is accurate. But the production efficiency is low and the mold cost is high, so the price is very expensive. By adopting the method of cluster drawing, dozens or even hundreds of wires are drawn on a mold at the same time, which greatly improves the production efficiency and reduces the cost. Cluster drawing is to draw the raw metal wire in a sheath (such as a copper sheath), repeat it for many times, and add an annealing process in the middle. After reaching a certain diameter, it will be cut into sections, put together, and then installed in the sheathing material to continue. Draw until the required fiber diameter is obtained. The sheathing material can be dissolved with acid (eg nitric acid), and finally the desired metal fibers are obtained.

2) Spinning method
The spinning method can directly produce metal fibers from liquid metal, and the cost is low, but special equipment is required. For example, after the metal is melted, mechanical force or gas pressure is used to make the molten liquid flow out of the small holes at the bottom of the container and solidify in a suitable atmosphere. After the molten metal flows out of the fine pores, shortly after solidification, the bonding force between the metal fiber grains is very weak and has "hot brittleness", so a small force can make the metal fiber cut into short fibers. Therefore, by adding a certain shearing force to the falling metal fibers, short metal fibers of the same length can be obtained. Shear force can be generated by impact of the metal plate inclined to the metal fibers. The method for preparing metal fibers has the advantages of simple process, high speed, no pollution such as oil and water, and no residual stress.

3) Cutting method
The cutting method uses solid metal as raw material, and uses a tool to cut it into fibrous chips. The method is simple, the production cycle is short, and the cost is low, but it is difficult to obtain fibers with a uniform and smooth cross-section, and it is mainly used to produce short metal fibers.

4) Grinding method
The metal is ground on a grinding machine equipped with a certain abrasive (high hardness material), and the metal fiber of the required diameter can be obtained by adjusting the amount of bite, the feeding amount and the selection of the abrasive particle size on the grinding machine. The thickness of metal fibers is affected by many factors. For example, the larger the feeding amount, the finer the obtained metal fibers, and the coarser the abrasive particle size, the thicker the obtained metal fibers. In this way, fine nickel or nickel alloy wires and strong and tough metal fibers such as nickel-iron alloys can be prepared.

5) Plating metal sintering method
Electroless metal plating, vacuum evaporation and metal slurry infiltration are carried out on organic fibers, or electroplating is performed on the surface of organic fibers after conducting conductive treatment, and then the organic substances are thermally removed in a reducing atmosphere and sintered, or sintered in the atmosphere ( Or pyrolysis) organic matter, then reduction annealing to remove oxides, and hollow metal fibers can be obtained.

6) Other methods
The metal powder or metal oxide and organic binder are prepared into slurry, which is extruded from a micro-hole spinneret to form a fiber. After the binder is removed at high temperature, it is sintered in a reducing atmosphere, or directly heated in a reducing atmosphere. By removing the binder, metal fibers can also be obtained. Also, if Ni(OH)2 powder is used with a binder and a paste, it is extruded into fibers, and then reduced and sintered to obtain fibrous nickel.