Polytherms of the Wetting Angles of Pb-Ni (0.3 at %) Melt on Nickel Substrates

Resumo

Polytherms of the wetting angle of Pb-Ni (0.3 at %) melt on pressed nickel substrates and substrates cut from a plate of nickel of grade NP-2 are studied in the temperature range from the melting point to 850°C by the sessile drop method in a vacuum chamber with a residual pressure of 10^-2 Pa. The wettability thresholds are found. The wetting of both pressed substrates and NP-2 nickel begins at a temperature of 500°C or higher. After crystallization, the morphology of the droplet surface and the zones near it is studied using scanning electron microscopy. Pb_nNi_m intermetallides of pyramidal form are detected, and zones where the melt spreads along the grain boundaries followed by the crystallization and formation of fibrous structures are found.