酸蚀Al粉对Al-聚氨酯复合涂层光泽度与红外发射率的影响

Effects of acid-etched Al powders on glossiness and infrared emissivity of Al-polyurethane composite coatings

在不明显升高Al-聚氨酯(PU)复合涂层红外发射率的前提下,通过酸蚀Al粉提高Al粉表面粗糙度的方法来明显降低涂层的光泽度。系统研究了Al粉酸蚀时间对Al-PU复合涂层的微结构、光泽度、红外发射率及力学性能的影响。结果表明:Al粉酸蚀可明显降低涂层的光泽度,酸蚀10min即可使涂层的光泽度从20.1降低为13.0,而Al粉酸蚀对涂层的微结构基本没有影响,对涂层发射率的影响非常有限,酸蚀50min仅使涂层的发射率从0.208增大为0.254,仍然具有较低的发射率。酸蚀20min可使涂层同时具有较低的光泽度和发射率,其值分别为12.8和0.228。涂层的力学性能对Al粉酸蚀处理并不敏感,处理前后涂层的硬度、附着力和耐冲击强度等力学性能分别可达到3H、1级和50kg·cm。

The method of improving the surface roughness of A1 powders by acid etching AI powders was used to obviously reduce the glossiness of Al-popyurethane（PU） composite coatings under the premise of not obviously rai- sing the infrared emissivity of the coatings. The effects of acid etching time of A1 powders on the microstructure, glossiness, infrared emissivity and mechanical properties of the A1-PU composite coatings were systematically stud- ied. The results show that acid etching of A1 powders can significantly reduce the glossiness of the coatings. Acid etching 10 rain can make the coating＇s glossiness decrease from 20.1 to 13.0, but it has no obviously effect on mi- crostructure of the coatings. And the effect on the emissivity of the coatings is very limited. Acid etching 50 min on- ly can make the coating-s emissivity increase from 0. 208 to 0. 254, still has a lower emissivity. Acid etching 20 min can make the coatings have lower glossiness and emissivity which are 12.8 and 0. 228, respectively. The me- chanical properties of the coatings are not sensitive to acid etching of A1 powders, the hardness, adhesion strength and impact strength of the coatings before and after the treatment can reach 3 H, 1 grade, and 50 kg. era, respectively.