METHOD OF MAKING ARTICLES FROM ULTRA-FINE GRAINED SILICON GRAPHITE Russian patent published in 2019 - IPC C01B32/21 C01B32/956 C04B35/565 C04B35/532 C01B32/15 B82B3/00 B82Y40/00 

FIELD: chemistry; metallurgy.

SUBSTANCE: invention is intended for chemical and metallurgical industry and can be used in manufacturing of bearings, seals and facing plates. First, press mass is prepared on the basis of graphite powder of 5–20 mcm fraction mixed with technical carbon, including nanosized, and polysiloxane or polysilazane binder. Then billet is formed by pressing and polymerisation of binder. Obtained workpiece is fired at 1000–1200 °C, respectively in vacuum or at atmospheric pressure in argon medium and at 1500–1550 °C and pressure in the reactor is not more than 36 mm Hg. After that silicizing is carried out by vapour-liquid-phase method at mass transfer of silicon into pores of material by mechanism of capillary condensation of its vapours at heating from 1300 to 1500 °C at reactor pressure of not more than 36 mm Hg. with subsequent exposure at temperature 1550–1600 °C for 1–2 hours and cooling in silicon vapour. Workpiece billet annealing and its sieving can be performed in single technological process. Billet annealing based on polysiloxane binder can be carried out at atmospheric pressure with subsequent heating to 1300 °C. Before mass transfer of silicon into pores of workpiece material based on polysilazane binder can be performed its heating to 1500–1550 °C and intermediate cooling up to 1300 °C at temperature higher than that of silicon vapour.

EFFECT: improving operational characteristics of items from siliconized graphite, as well as reproducibility of obtained results.

4 cl, 1 tbl, 6 ex