锆粉加热纸燃烧机理研究

研究了热电池用Zr-BaCrO4加热纸(锆粉加热纸)的燃烧机理.X射线衍射光谱法(XRD)物相分析表明,在Zr-BaCrO4加热纸中,若Zr粉量不足,则燃烧后物相成分为BaZrO3和CrO;若Zr粉过量,物相成分还包括Zr2O.在Zr粉量不足的加热纸中,燃烧包含Zr和BaCrO4发生氧化还原反应生成BaZrO3和CrO,及BaCrO4分解的两个反应;在Zr粉过量的加热纸中,燃烧包含Zr和BaCrO4发生氧化还原反应生成BaZrO3和CrO,及产物为BaO,CrO和Zr2O的另一个氧化还原反应.计算得Zr粉过量时加热纸燃烧产物中Zr2O的标准焓变值△fHθZr2O(s)约在-1 290～-1 296kJ/mol范围;经热重-差热分析(TG/DSC)、理论计算及加热纸灰烬于1 200℃氧化后的物相分析都证实其热稳定性高于1 200℃.Zr-BaCrO4加热纸燃烧机理的确定有助于精确设计加热纸成分、控制电池输入热量、提高电池质量及安全性,并为电池的数字化设计提供有效参数.

Combustion mechanism of Zr-BaCrO_4 heat paper

The thermal battery used Zr-BaCrO_4 heat paper combustion mechanism has been studied. It is identified by X-ray diffraction (XRD) analysis that the main compositions of the combustion products are BaZrO_3 and CrO when zirconium powder mass is insufficient, otherwise, the main compositions are BaZrO_3, CrO and Zr_2O. When zirconium powder mass is insufficient, the Zr-BaCrO_4 heat paper combustion mechanism are Zr+BaCrO_4→BaZrO_3+CrO+△H and BaCrO_4→BaO+CrO+O_2↑+△H, otherwise, its depends on reactions of Zr+BaCrO_4→BaZrO_3+CrO+△H and 4 Zr+BaCrO_4→BaO+CrO+2 Zr_2O +△H. When zirconium powder mass is excessive, Zr_2O is one of the main results, which calculated standard formation enthalpy value (△_fH_(Zr_2O(s))~θ) range is from - 1 290 kJ/mol to -1 296 kJ/mol. The thermal stability of Zr_2O is very high, which has been verified by TG/DSC analysis, thermodynamic calculations and X-ray diffraction (XRD) analysis when the combustion ashes were oxidized at the temperature of 1 200 ℃. Once the combustion mechanism has been verified, Zr-BaCrO_4 heat paper combustion heat output can be designed and calculated accurately, and then the thermal batteries performance and safety can be improved greatly.