basic principles: The molten metal zinc and the binder phase metal (such as drill, nickel) in the cemented carbide can form a low melting point alloy. The bonding metal is separated from the cemented carbide to form a zinc-cobalt solid solution alloy liquid with zinc, thereby destroying the structure of the cemented carbide and making the dense alloy into a sponge-like material. Since zinc does not chemically react with carbides of refractory metals, the vapor pressure of zinc is much higher than the vapor pressure of the drill at a certain temperature (when the temperature exceeds 925 ° C, the zinc evaporates into zinc vapor, and the drill is almost non-volatile, The zinc is separated from the cobalt), and the zinc is separated by evaporation and recycled by the difference in vapor pressure.
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