铸造用自硬磷酸镁粘结剂砂性能的研究

Study on Properties of Self-Hardening Magnesium Phosphate Binder Sand for Casting

磷酸盐粘结剂是铸造型砂粘结剂的发展方向之一,但传统磷酸盐粘结剂存在抗湿性差等不足。以氧化镁和改性磷酸盐为主要组分制备磷酸镁粘结剂,通过改变氧化镁与磷酸盐(M/P)的比例,研究磷酸镁粘结剂铸造型砂的性能。结果表明:磷酸镁粘结剂砂具有自硬性;磷酸镁粘结剂用量占原砂质量10%时,1 h抗拉强度可达到0.3 MPa,24 h抗拉强度超过1.0 MPa,发气量均低于10 mL/g;磷酸镁粘结剂制备的型砂抗湿性优异;温度超过700℃以上时溃散性优异,筛余率为0。可以认为磷酸镁粘结剂是一种性能优良的无机型砂粘结剂。

Phosphate binder is one of the development directions of casting sand binder,but the traditional phosphate binder has some shortcomings,such as poor moisture resistance.Magnesium phosphate binder was prepared with magnesium oxide and modified phosphate as the main components.The properties of the magnesium phosphate binder casting sand were studied by changing the ratio of magnesium oxide to phosphate(M/P).The results show that the magnesium phosphate binder sand has self-hardening;when the amount of the magnesium phosphate binder accounted for 10%of the mass of raw sand,the tensile strength reached 0.3 MPa in 1 h,the tensile strength exceeded 1.0 MPa in 24 h,and the gas evolution was less than 10 mL/g;the molding sand prepared by the magnesium phosphate binder had excellent moisture resistance;when the temperature exceeded 700℃,the collapsibility was excellent,and the sieve residue rate was 0.It can be considered that the magnesium phosphate binder is an inorganic molding sand binder with excellent properties.