Application of tantalum-niobium thin strip

Metal tantalum dielectric high purity, stable performance, large dielectric constant, therefore, made of thin slices specifications tantalum capacitor (deep-drawing cup made of convex shell) highest bulk densities, small volume, light quality, high working temperature, the advantages of high reliability and resistance to shock, can effectively meet the requirements of electronic equipment for components (capacitor element need to directly contact with high temperature assembly solder, only the heat tolerance of tantalum assembly solder).Tantalum capacitors have been widely used in military radar, aircraft, missile and other systems. At present, the application of tantalum capacitors has been rapidly expanded to the civil field, among which the demand for computers, communication equipment and other industries is large, and the demand for tantalum electrolytic capacitors for household appliances such as televisions is also increasing. Tantalum capacitors are mainly developed in the direction of miniaturization, low cost, high pressure resistance and high reliability. Currently, more than half of the tantalum processed materials consumed worldwide each year are used to make tantalum capacitors. Looking forward to the future, all kinds of chip tantalum capacitors will maintain a good growth momentum. At present, the whole tantalum shell cannot be produced in China. The main reason is that the thin tantalum chip is prone to cracking, wrinkling, orange peel, ear making and other phenomena when the tantalum shell is produced deeply in China. As a result, the finished product rate is low, which makes it difficult to meet the requirements of high performance and high reliability.

With the continuous development of industrial technology, the application of tantalum in the form of thin specification strips has become a new development direction, especially with the development of superconducting technology, the market demand for tantalum strips is increasing gradually. For example, tantalum belt is used as the main material of superconducting wire barrier layer in the production of superconducting wire. In the field of superconducting production, high purity, fine and uniform grain size and good elongation are required. The fine and uniform grain structure can improve the deformation uniformity of tantalum strip and enhance the deep tensile ductility, so that the tantalum strip can still be uniformly deformed at nearly 100% processing rate and can be thin to 2-4 m without rupture.

In the national high-tech product catalogue, fine crystal tantalum chips with thickness of 0.05-2.5mm, width ≤500mm, length ≤ 1500mm,Rm≥270MPa,Rp0.2≥120MPa, A≥30%, grain size ≤20 m, flatness ≤6%, hardness ≤Hv120 are recommended. The products are mainly used in electronics, textile and other industries.

Niobium is widely used as electrode material because of its good plasticity, high conductivity and overflow power. Niobium band is one of the main materials used to make electrode head of cold cathode fluorescent lamp (CCFL). Compared with molybdenum band, niobium band has higher deep drawing ratio and is more suitable for automatic production. CCFL, as a liquid crystal screen backlight, has solved the problems of low brightness and short service life. It has more than 50% parts and degrees in manufacturers of backlight, and belongs to the product with long production cycle in the electronics industry. In addition, niobium belt is used to make the key parts of high pressure sodium lamp, such as the niobium belt connector used to make conductive path.

Due to the small size of niobium raw material, the niobium belt produced in China has some problems, such as short length, unstable elongation and low grain size. The deep drawing performance of niobium strip depends not only on the forging and rolling process, but also on the heat treatment (vacuum annealing).