等离子喷涂与溶胶-凝胶法组合制备中高温太阳能选择性吸收复合涂层

Preparation of Medium-High Temperature Solar Selective Absorbing Composite Coating by Plasma Spraying plus SolGel Process

为了制备出高效的非真空、中高温太阳能选择性吸收涂层,先在光亮Cu片上等离子喷涂Cr-Al2O3金属陶瓷吸收层,再用溶胶-凝胶法在其上制备了SnO2选择性透过膜,对复合涂层的相结构、表面形貌、光学性能进行了研究。结果表明:金属陶瓷吸收层由金属颗粒Cr与Al2O3组成,物相稳定,表面凹凸不平,气孔较多,发射率较高;覆盖SnO2选择性透过膜后金属陶瓷吸收层的孔隙被填补,表面粗糙度降低,发射率显著降低。

Cr-Al2O3 cermet absorbing coating was firstly prepared on bright copper plate by plasma spraying.Then SnO2 selective transparent film was prepared atop the plasma sprayed cermet absorbing coating via sol-gel process.The phase structure,morphology and optical properties of the composite coating were analyzed.It was found that as-sprayed cermet absorbing coating consisted of stable phases of metal Cr and Al2O3,and had a rough surface structure with a large amount of pares,showing a high emissivity.When SnO2 selective transparent film was fabricated atop the plasma sprayed cermet absorbing coating,the pores in resultant composite coating were filled up,leading to decreased surface roughness and significantly decreased emissivity.