▎ 摘　　要

NOVELTY - Casting magnesium alloy protective coating system comprises matched sealing varnish and anticorrosive primer. The sealing varnish comprises A component and B component with mass ratio of 5:1 to 3:1, before construction, mixing A component and B component uniformly. The anti-corrosion primer comprises propyl component and butyl component at mass ratio is 7:1 to 5:1, before construction, mixing component C and component uniformly. The component A comprises silicon modified phenolic epoxy resin and mixed solvent A. The B component comprises polyamide, polyether amine A and mixed solvent B. The acrylic component comprises organic-inorganic hybrid resin, lemon yellow, aluminum trippolyhosphate, talcum powder, mica powder, graphene, dispersant, flatting agent, antifoaming agent and mixed solvent C. The butyl component comprises phenolic aldehyde amine, polyether amine B and mixed solvent D. USE - Casting magnesium alloy protective coating system ADVANTAGE - The casting magnesium alloy protective coating system has good adhesive force, sealing hole performance, good protection effect, high humidity, high temperature and acidic atmosphere. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: 1. a method for preparing casting magnesium alloy protective coating system, which involves: a. preparing sealing varnish by preparing materials according to proportion, dissolving and diluting silicon modified phenolic epoxy resin by mixed solvent A while stirring, filtering and discharging to obtain methyl component, preparing sealing varnish component by uniformly mixing polyamide, polyether amine A and mixed solvent B under stirring, filtering and discharging to obtain B component, mixing first component and second component according to proportion to obtain sealing varnish; and b. preparing anticorrosive primer by preparing anti-corrosion primer C component, adding organic-inorganic hybrid resin, dispersing agent, flatting agent, antifoaming agent, lemon yellow, aluminium tripolyphosphate, talcum powder, mica powder, graphene and mixed solvent C into cylinder, grinding until fineness is less than 30 m, filtering and discharging to obtain acrylic component, preparing anti-corrosive primer component by mixing phenolic aldehyde amine, polyether amine B and mixed solvent D uniformly under stirring, filtering and discharging to obtain the butyl component, mixing C component and component B according to proportion to obtain anti-corrosion primer; and 2. a method for using casting magnesium alloy protective coating system, which involves: a. using potassium dichromate-manganese sulfate chemical in HB/Z 5078-78 for casting magnesium alloy oxidation method for surface treatment; b. spraying sealing varnish, after 24 hours of surface treatment, controlling dry film thickness of sealing varnish at 10-15 μm; and c. spraying anti-corrosion primer after sealing varnish is dried, and controlling dry film thickness of primer at 30-40 μm.