Badanie procesów modyfikacji plazmowej proszków W i Re oraz mieszanek W-Re

W artykule przedstawiono wybrane wyniki badań sferoidyzacji plazmowej proszków wolframu i renu oraz mieszanki proszkowej sporządzonej z tych metali. Wymienione materiały mogą być użyte w produkcji spieków przeznaczonych na rdzenie pocisków przeciwpancernych. Sferoidyzację wymienionych proszków wykonano przy zastosowaniu stanowiska do natryskiwania plazmowego, w komorze wypełnionej gazem obojętnym. Przedstawiono zmiany wielkości i kształtu cząstek proszków zachodzące w procesie sferoidyzacji, a także wyniki badań naprężeń wewnętrznych w cząstkach proszków.

Many methods for modification of shape and properties of powder particles are used in powder metallurgy. They are devoted to improvement in characteristics of a final product - the sinter. One of the methods is powder spheroidization in plasma jet which gives the following effects: the powder is characterized by high compressibility and good technical properties while particle roughness and cracks can be eliminated, and so on. Selected results of plasma spheroidization of tungsten and rhenium sinters intended for production of penetrators and high-current contacts are presented in the paper. The spheroidization of the above-mentioned powders was performed on the stand for plasma spraying in a chamber filled with neutral gas. In the paper, the pictures of tungsten, rhenium and mixed W-Re powder particles before and after spheroidization are presented. Grain size analysis of the produced powders was carried out and tests of their other properties were also performed. Exemplary grain size distributions of tungsten powder particles before and after plasma spheroidization are presented Presented results show that powders with spherical particles can be produced using device for plasma spraying. This process increases particle size for powders with fine granulation – in our case for tungsten powders. Increase in particle size for powders with larger granulation is weaker. The internal stress level in powder particles can be enhanced due to plasma spheroidization and in some cases this rise is larger than for mechanical mixing or size reducing.