Based on the developed 140/270 mesh SLS coated sand

through selecting carbon powder

pyrite and boric acid with particle mesh size≤150as flame retardant

coated sand materials were designed and prepared with tripropellant composite flame retardant.By the laser sintering forming

green strength is 0.58 MPa

and post-processing strength reaches 2.34 MPa with gas release of 9.7g/mL.A coated sand mold prepared by the modified coated sand was used for pouring ZM2 magnesium alloy.And the surface qualified magnesium alloy parts were produced successfully wit tensile strength of 172 MPa and elongation of 4%.Finally

by using the SLS coated sand mold（core）with flame retardants

the high-quality magnesium alloy castings were produced.