镍掺杂铝酸镧涂层的制备及其红外辐射性能

Preparation and infrared radiation characterization of Ni doped lanthanum aluminate coatings

采用溶胶-凝胶法合成了Ni2+掺杂的LaAlO3基红外辐射材料LaAl0.6Ni0.4O2.89(LANO),以其为辐射基料,利用喷涂工艺在氧化铝陶瓷片表面制备红外辐射涂层,考察了磷酸二氢铝、铝溶胶、硅溶胶和钠水玻璃4种粘结剂对涂层物相组成、热稳定性和红外辐射性能的影响.结果表明,以LANO为辐射基料、铝溶胶为粘结剂时,涂层红外辐射性能最佳,3~5mm波段红外发射率达0.93;所制涂层具有良好的抗热震性能,50次热震后涂层未明显剥落失效;涂层具有显著的强化辐射传热效果,节能率达31.7%.

Ni ion doped LaAlO3-based infrared radiation materials were synthesized with lanthanum nitrate,aluminum nitrate,and nickel nitrate as starting materials via sol-gel method. Infrared radiation coatings were then prepared on the surface of alumina ceramic substrate by spraying process with inorganic binders of aluminium dihydrogen phosphate,aluminum sol, silica sol and sodium silicate,respectively.The thermal stability of the powder was analyzed by thermogravimetri-differential thermal analyzer. The XRD,ultraviolet-visible-near-infrared spectrophotometer and dual-band IR-2 emissivity tester were used to study the crystalline phase,reflectance and the 3~5μm infrared emissivity of powder and coatings, respectively.The thermal shock resistance of the coatings were tested by air cooling.In addition,the effects of the binders on the phase composition,thermal stability and infrared emissivity of the coatings were also investigated.The results showed that Ni ion doping improved the performance of infrared absorption of LaAIO3 coatings,the infrared emissivity as high as 0.94 in the spectral region of 3~5μm,which was 161% higher than that of LaAIO3.The coatings had the least impurity phase in case of aluminum sol as binder and at the same time the coatings had the highest infrared emissivity and the best thermal shock resistance.The infrared emissivity of the coatings was as high as 0.95 and 0.93in the band of 0.76-2.5 and ~5μm respectively.Furthermore,the coatings also had good thermal shock resistance,it's did not appear significantly peeling failure phenomenon after 50 thermal shocks.The coatings had a significant effect on enhanced radiation heat transfer,and the experimental energy saving rate reached 31.7%. This new type of high emissivity infrared radiation coatings had promising application in the field of thermal energy saving.