Study On Coating To Improve Surface Stability Of Sodium Silicate Sand

The themes of industrial development in the 21 st century include green,clean and environmentally friendly.According to the requirements mentioned in the "Eleventh Five-Year Plan",China should unswervingly follow the path of scientific development,build a resource-saving and environment-friendly society,and emphasize the sustainability of development.Among casting molding materials,sodium silicate sand is a clean and less polluting material.However,sodium silicate sand has the following problems: surface loose sand,difficult reuse of old sand,poor collapsibility,etc.In this paper,it is proposed to spray the coating on the surface of the sodium silicate sand mold,aiming to improve the stability of the sand mold surface and promote the promotion and application of sodium silicate sand when the amount of sodium silicate is added.A variety of organic and inorganic materials(including aluminum dihydrogen phosphate surface enhancer,sodium silicate,white latex,RSI surface strengthener,MUS granules,E4 reagent,ZX-1 surface enhancer,ZX-2 powder,ZX-3 reagent)and their mixed solutions are used to spray the sodium silicate sand mold,aiming to improve the surface stability of the sodium silicate sand mold and improve its moisture absorption under the condition of less sodium silicate addition.Through a series of comparative experiments,ZX-1 type surface enhancer,ZX-2 type powder and ZX-3type reagent were selected in a certain proportion to make a mixed solution for spraying,and the coating was named ZX surface enhancer below.Through the test,it was known that 1.5% sodium silicate sand was sprayed as the matrix sample,and the coating formula was 20 g ZX-1 surface enhancer,0.25 g ZX-2powder and 15 g ZX-3 reagent.After spraying,the surface stability of the 1.5% sodium silicate sand sample was increased from 60.6% to 99.1%,the surface stability was greatly improved,and the 24 h compressive strength in the 98% humidity environment was increased from 0.435 MPa to 1.089 MPa,and the moisture absorption was grea ZX-1y improved.Through SEM analysis and infrared spectroscopy detection,it is known that ZX surface enhancer sprayed on the surface of the sand mold can well coat the surface sand grains,fill the sand gap between the sand particles,and can bond the surface sand together well after drying and curing to improve the strength of the surface;No chemical reaction occurred between the sodium silicate,ZX-1 surface enhancer,ZX-1powder and ZX-3 reagent.After spraying ZX surface enhancer on the surface of the mold,the casting test showed that there were no defects such as sand inclusion,sticky sand and pores on the surface of the casting,and the sand mold fell out was simple and had good collapsibility.The surface shape of the casting is complete,angular and without notches.