Effects of Synthesis Process on the Properties of La1−xSrxMnO3 Materials for Thermal Control Coatings

Lanthanum strontium manganate (La1−xSrxMnO3) is considered a highly promising material for the development of intelligent thermal control coatings due to its exceptional properties. Recent studies on this material have primarily utilized solid-state synthesis as the main preparation method. Research efforts have predominantly focused on investigating the effects of material composition, heat treatment processes, and other factors on the properties of the synthesized material. There has been a limited amount of research investigating the influence of chemical precipitation process parameters on the properties of the synthesized La1−xSrxMnO3 material. In this study, the intelligent thermal control coating material La0.8Sr0.2MnO3 was synthesized using the chemical precipitation method. The effects of varying precipitant concentrations on the properties of the synthesized material were investigated. When the precipitant concentration is 12 wt.% or 15 wt.%, the synthesized powder agglomerates predominantly form three-dimensional blocky structures after sintering. At lower concentrations such as 6 wt.% and 9 wt.%, the powder agglomerates predominantly form two-dimensional sheet-like structures after sintering. At precipitant concentrations of 6 wt.% and 9 wt.%, the strontium content in the synthesized powder becomes significantly lower than the designed theoretical value. When the precipitant concentration is relatively high, localized manganese aggregation occurs in the synthesized lanthanum strontium manganate material. The temperature dependence of the emittance test result indicates that the emissivity variation of La0.8Sr0.2MnO3 material synthesized using 12 wt.% ammonia solution as precipitant reaches 0.428 from 173 K to 373 K, demonstrating excellent emissivity modulation performance.