有机硅高温涂料耐热性及其影响因素研究

Performance of Organosilicone Heat Resistant Coating and Its Influencing Factors

以有机硅296和聚碳硅烷为基料,低熔点玻璃粉、BN、SiC、ZrO2和Al2O3为填料,制备了耐高温涂料。通过正交试验,考核了填料体系设计对涂层耐热性的影响规律,制备了耐温达700℃的有机硅高温涂层。结果表明,影响涂料耐热性和附着力的主要因素为低熔点玻璃粉和BN,其次为ZrO2和Al2O3。低熔点玻璃粉在高温下的"二次成膜"作用可以有效提高涂层的耐热性、改善粉化现象,但过多的用量会造成涂层开裂和脱落。BN作为导热填料,与其他填料按一定比例加入到涂料中,可以提高涂层的耐热温度到700℃。ZrO2和Al2O3较大的热膨胀系数减少了涂层和基体的热失配,利于提高其耐热性。

A organosilicone coating with high temperature resistance was prepared with organosilicone 296, polycarbosilane as binder and low melting-point glass powder, BN, SiC, ZrO2 Al2O3 as fillers. By orthogonal test, the effects of coating formulation on heat re- sistance were studied and organosilieone coating resistant to 700 ℃ was prepared. The results showed that the main influencing factors on the heat resistant performance of the coating were low melting-point glass powder and BN, fallowed by ZrO2 and Al2O3. ＂Second film＂ function of low melting-point glass powder had a good effect on reducing the pulverization phenomenon and improving heat resist- ance of coating, but excessive usage would result in cracking and exfoliation. High thermal conductivity of BN could improve the heat resistance to 700 ℃ High thermal expansion coefficient 0f ZYO2 and A1203 could improve the heat resistance by reducing the thermal mismatch between coating and base metal.