The insulative properties of intumescent coatings will degrade after aging and the degradation process is affected by such factors as coating type,environmental condition,coating thickness and service time.In order to investigate how insulative properties of the coatings are affected by those factors,accelerated aging tests and fire tests were carried out on 78 steel specimens coated with intumescent coating.Test results show that type-A coating is vulnerable to hydrothermal environment; thicker coatings delay degradation process; effective thermal conductivities of intumescent coatings increase with prolonged service time and the relationship of effective thermal conductivity-service time is affected by coating type and environmental condition.Physical and chemical equilibrium of intumescent coating system is reached in condition No.1 after 10 years (21 cycles).Effective thermal conductivities of intumescent coating increase progressively in condition No.2 and condition No.3.%膨胀型钢结构防火涂层隔热性能的退化程度受涂料类型、环境条件、使用时间、涂层厚度等因素的影响.为考察上述因素对膨胀型防火涂层耐老化性能的影响,进行了3种工况(变化参数为老化环境及涂料类型)共计78个试件的湿热老化试验及隔热性能试验.结果表明:单组分溶剂型防火涂料在高温高湿环境下更易发生老化；增加涂层厚度可以延缓老化进程；随使用时间延长,涂层防火隔热性能下降,等效导热系数增大,涂层等效导热系数随使用时间变化的规律与涂料类型和环境条件有关.工况1中涂层在老化后期的等效导热系数变化很小,此时涂层与环境所构成的体系已达到一个稳定的平衡状态；工况2和工况3中涂层等效导热系数随时间呈现出递增趋势.
展开▼
