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采用溶胶–凝胶法合成了Ni离子掺杂的LaAlO_3基高发射率红外辐射陶瓷粉体。研究表明:Ni离子掺杂能够显著提高LaAlO_3基陶瓷粉体的红外吸收性能,当Ni离子掺杂量为40%(摩尔分数)时,所制备的LaAl_(0.6)Ni_(0.4)O_(2.89)粉体红外吸收性能最佳;以LaAl_(0.6)Ni_(0.4)O_(2.89)为基料,采用铝溶胶为黏结剂,制备出3~5μm波段发射率高达0.93的红外辐射陶瓷涂层。Ni离子掺杂能够显著提高LaAlO_3基陶瓷材料红外辐射性能的物理机制在于:Ni离子进入LaAlO_3晶格后,在其带隙中引入了Ni~(3+)和Ni~(2+)杂质能级,形成了跃迁激活能仅需0.03eV的Ni~(3+)?Ni~(2+)小极化子吸收带;通过小极化子跃迁吸收,增强了LaAlO_3基陶瓷材料的红外辐射性能。这种新型的高发射率红外辐射陶瓷涂层在热工节能领域具有广阔的应用前景。
Ni-doped LaAlO 3 -based high emissivity infrared radiation ceramic powders were synthesized by sol-gel method. The results show that the NiAl doping can significantly improve the infrared absorption properties of LaAlO_3 based ceramic powders. The LaAl_ (0.6) Ni_ (0.4) O_ (2.89) The infrared absorption properties of the powders were the best. LaAl_ (0.6) Ni_ (0.4) O_ (2.89) was used as the binder and aluminum sol was used as the binder to prepare the infrared radiation ceramic coating with the emission of up to 0.93 in 3 ~ 5μm band. Ni ion doping can significantly improve the infrared radiation properties of LaAlO_3-based ceramic materials, the physical mechanism is: Ni ions into the LaAlO_3 lattice, the introduction of the band gap Ni ~ (3 +) and Ni ~ (2+) impurity level Ni 3 + Ni 2+ small polaron absorption band with a transition activation energy of only 0.03eV was formed. The infrared radiation of LaAlO 3 -based ceramics was enhanced by the absorption of small polaron transitions. This new type of high emissivity ceramic coating has broad application prospects in the field of thermal energy saving.