P110 ERW Casing Vacuum Heat Treatment

Tantalum powder in high vacuum and high temperature re-coagulation into new particles in the process. This is an important step in the production of capacitive grade tantalum powder. The process can remove some of the impurities of tantalum powder and improve the physical properties of tantalum powder, which play a role in improving the performance of tantalum powder.

The P110 erw casing produced by the sodium heat reduction process contains a variety of metal and nonmetallic impurities, which form a solid solution with tantalum or in the form of intergranular inclusions in the tantalum powder; moisture and hydrogen are adsorbed on the surface of the tantalum powder. These impurities in the tantalum anodic oxide film on the formation of defects on the oxide film defects, but also due to power failure caused by heat oxidation of amorphous oxide film, resulting in increased leakage current capacitor, breakdown voltage decreases. Since the vacuum heat treatment temperature is generally below 1773K, only the gas impurities adsorbed on the surface of the tantalum powder and some low melting point metal impurities can be removed. Therefore, it is necessary to control the impurity content of the tantalum powder before the heat treatment. In the process of vacuum heat treatment, the moisture content of tantalum powder is rapidly evaporated at 373 ~ 423K, and the hydride is decomposed at 873 ~ 973K. The alkali metal and its compounds are volatilized at the temperature of 1373 ~ 1873K. Most iron, nickel and chromium destabilized in the form of low melting oxide. In addition to the impurity effect increases with the increase in vacuum and temperature and the heat treatment time. Carbon in the 1273 ~ 18.73K temperature vacuum and tantalum powder excessive oxide, the formation of CO gas escape to remove part of the oxygen and carbon. When the carbon is not complete, the residual carbon and tantalum to produce the melting point of up to 4073K TaC crystal phase, TaC in the tantalum oxide film in the formation of nuclear center, the formation of low resistance zone, the tantalum anode leakage current increases. Oxygen is a high specific capacity of tantalum powder sensitive impurities, must be controlled within the specified range, so that both can remove carbon and other metal impurities, and will not cause tantalum wire crisp. Excessive oxygen can lead to tantalum anodic oxide film defects, so that the electrical properties of tantalum anode deterioration.

A worker from a steel pipe company, which is located in China.