Abstract

The composition of gels and xerogels, as well as their transformation during heating and dehydration, determine the thermochemistry of solution combustion synthesis reactions. An improved descriptive thermodynamic model of combustion processes was formulated on the basis of the investigated formation of complex compounds of metal ions with organic fuel (glycine, citric acid, urea, and PVA) in nitrate solutions. The intensity of SCS reactions was found to depend on the strength of Ni²⁺–ligand complexes. The effect of heat loss during combustion on the ΔT_max value was analyzed for the model system Ni(NO₃)₂·nH₂O–Fuel–H₂O. It was found the heat loss occurs due to the presence of various amounts of structurally-bound water in gels and xerogels before the combustion.

The temperature profiles of combustion during the synthesis of NiO with different types of fuel at φ = 1.0.

中文翻译：

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凝胶中残留水含量对溶液燃烧合成温度的影响

摘要

凝胶和干凝胶的组成以及它们在加热和脱水过程中的转变决定了溶液燃烧合成反应的热化学性质。在研究的金属离子与有机燃料（甘氨酸，柠檬酸，尿素和PVA）在硝酸盐溶液中形成复杂化合物的基础上，建立了改进的燃烧过程描述性热力学模型。发现SCS反应的强度取决于Ni 2 ⁺ -配体配合物的强度。分析了模型系统Ni（NO ₃）₂ · n H ₂ O–燃料–H _2的燃烧过程中热损失对ΔT_最大值的影响。O.发现由于燃烧前凝胶和干凝胶中存在各种数量的结构结合水而发生热损失。