Research On Preparation And Thermal Insulation Properties Of NaZnPO₄ Based Porous Near Infrared Reflective Materials

In this paper, NaZnPO4 and its doped materials NaZn(R)PO4 were prepared via the method of coprecipitation and calcine, and the raw materials were Zn(NO3)·6H2O、phosphoric acid、soda ash and other compound(MnCl2·4H2O、Ni(NO3)2·6H2O Cr(NO3)3·9H2O、Bi(NO3)3·5H2O). The structure, morphology and color were examined by XRD, SEM and Colorimeter, the Vis-NIR reflection was measured by UV-Vis-NIR Spectrophotometer, the acid(alkali) resistance and heat-insulation were also studied. Corner reflectors were designed, and its RSC were studied. In order to strengthen the decoy jamming effect, NaZn(R)P04 were used as thermal barrier to connect infrared medicine column and millimeter wave foils. Zn/Ni molar ratio 0.80:0.20, calcined at 800℃, was the best reaction conduction, Ni was well doped into NaZnPO4 to produce NaZn(Ni)PO4, the product was orange yellow, acid(alkali) resistance was well, the average reflection at near-infrared(NIR) band can reach 69.33%, was 8.17% higher than common orange-yellow pigment, its highestnear-infrared reflection can reach 82.85%,. (2)The best reaction conduction of Mn doped experiment was Zn/Mn molar ratio 0.90:0.10, calcined temperature 800℃, the product of Mn doped into NaZnPO4 was fuchsia, acid(alkali) resistance was well, the highest reflection at near-infrared(NIR) band can reach 85.2%, it can be used as effective heat insulation material. (3)The best conduction to prepare NaZn(Cr)PO4 was Zn/Cr molar 0.90:0.10, calcine temperature was 900℃. NaZn(Cr)PO4 was green and can well resistant acid or alkali. It have abundant micro-porous and effectively reflect near-infrared radiation, at wavelength of 780-2500nm, its highest reflection can reach 83.15%, average reflection was 69.12%,6.16% higher than common green pigment. Under the same near-infrared radiation, NaZn(Cr)PO4 can reduce 18.3% heat flux than common green pigment. (4)Analysis measure resulted that rare earth element Bi can enhance the near-infrared reflection of NaZn(Tm)PO4, Tm/Bi molar ratio 5:1 prepared precursor calcined at the optimum temperature, the of the products increased 1.14%、1.18%、1.46% compared with NaZn(Tm)PO4(Tm=Ni, Mn, Cr). Comprehensive analysis shows that transition element(Tm) doped into NaZnPO4 can obtain color recombination material which have abundant micro porous and high reflection at band of 780-2500nm. Its heat insulation is well than conventional coatings and acid resistance is quiet well, so does its alkali resistance. Empirical analysis shows that rare earth element Bi can enhance the near-infrared reflection of NaZn(Tm)PO4. This paper studies accelerate the research and development of NaZnPO4 doped material in the field of heat insulation. As a kind of integrated heat insulation, NaZnP04 doped material has broad application prospects in daily life, industrial manufacture and military field.