The invention discloses a preparation method of a liquid-proof
coating adopting a gradient increasing structure, belongs to the technical field of
plasma chemical vapor deposition. The preparation method comprises the following steps: firstly, putting a base material into a
reaction chamber of a
plasma chamber, continuously vacuumizing the
reaction chamber till the vacuum degree of the
reaction chamber is 10-200 millitorrs, and inflating an
inert gas or
nitrogen gas; secondly, inflating first
monomer steam, second
monomer steam and third
monomer steam at the same time; starting
plasma discharge, and performing
chemical vapor deposition;
after discharge, turning off a plasma power supply, stopping inflation of the first monomer steam, the second monomer steam and the third monomer steam, continuously vacuumizing, inflating
atmosphere till an
atmospheric pressure after the vacuum degree of the reaction chamber is kept at 10-200 millitorrs for 1-5 min, and then taking out the base material. Through inflation of the first monomer steam, the second monomer steam and the third monomer steam at the same time, and through control over increase in the flows of the first monomer steam, the second monomer steam and the third monomer steam at different speeds, the prepared
coating has gradient changing structural
toughness and
hardness, can reduce stress
cracking and deformation, and has a relatively high barrier protection performance.