Even fluoropolymers are no threat to these barrels, which have a protective layer of nickel-rich boron alloy
containing molybdenum and a matrix of borides and carbides.
This is probably due to the higher metal circulation, which lifts heavier boron alloy
particles to the surface.
Now, a new diluted boron alloy
is available that minimizes aluminum content and combines titanium with rare earths for greater fluidity, eliminating the nozzle-clogging problem.