磷酸镁涂层高温后力学性能研究

Mechanical Properties of Magnesium Phosphate Coatings after High Temperature

磷酸镁涂层是一种新型、耐高温无机防火材料,同时,也是一种性能优异的工业钢结构无机防腐蚀材料。本文重点关注磷酸镁涂层在高温作用后的力学性能,通过试验系统研究了磷酸镁涂层在高温(100℃、200℃、300℃、400℃、500℃、700℃、900℃)作用后硬度、粘结强度等力学性能的变化,以及力学性能变化的微观机理。结果表明,高温后的磷酸镁涂层具有较好的完整性,表观无粉化、起泡、剥落和开裂等缺陷出现。相较于常温,高温后的磷酸镁涂层力学性能略有下降,其中300℃高温后的涂层粘结强度最低,且硬度下降最显著。此后随着温度升高,涂层力学性能有不同程度的提高。基于不同温度下微观表征和热重分析,揭示了造成磷酸镁涂层高温力学性能变化的四阶段高温演化机理。

Magnesium phosphate coating belongs to a new type of high temperature resistance inorganic fireproof material,and also an excellent inorganic anti-corrosion material for industrial steel structures.This article focused on the mechanical properties of magnesium phosphate coatings after high temperature action.Through the experiments,the changes in mechanical properties such as hardness and bonding strength of magnesium phosphate coatings after high temperature(100 ℃,200 ℃,300 ℃,400 ℃,500 ℃,700 ℃,900 ℃) action,as well as the microscopic mechanism of the changes in mechanical properties were systematically studied.The results show that the magnesium phosphate coating has good integrity after high temperature action,and there are no defects such as powdering,blistering,peeling and cracking.Compared with room temperature,the mechanical properties of magnesium phosphate coatings after high temperature action decrease slightly.The magnesium phosphate coatings treated at 300 ℃ have the lowest bonding strength and the most obvious decrease in hardness.With the temperature increasing above 300 ℃,the mechanical properties of the coatings improve in different degree.Based on the microscopic characterization and thermogravimetric analysis at different temperatures,the four-stage high temperature evolution mechanism that caused the changes of the high temperature mechanical properties of the magnesium phosphate coatings was suggested.