A pure crystalline γ-FeNi alloy powder was fabricated through the one-step process of sol–gel combustion. An experiment was conducted in inert atmosphere with the hexamethylenetetramine (HMTA) used as an oxygen-free fuel and metal nitrites as oxidizers. It was demonstrated that fuel-to-oxidizer ratio is a critical parameter to produce pure γ-FeNi alloy. A concentration of the fuel necessary for the alloy synthesis is three times higher (φ = 3) than at the stochiometric molar ratio. The ~1100 K maximum temperature, 830 K/s heating and 170 K/s cooling rates and the total reaction time of ~3 s are characteristics of the optimized sol–gel combustion synthesis of the γ-FeNi alloy powder. A mechanism of the alloy formation through the coordination metals—HMTA complex was proposed and experimentally verified. Microstructural and magnetic properties of the synthesized material are also investigated and discussed.

通过溶胶-凝胶燃烧的一步法制备了纯结晶的γ-FeNi合金粉末。在惰性气氛下进行了实验，以六亚甲基四胺（HMTA）为无氧燃料，以金属亚硝酸盐为氧化剂。结果表明，燃料与氧化剂的比例是生产纯γ-FeNi合金的关键参数。合金合成所需的燃料浓度高出三倍（φ = 3）大于化学计量摩尔比。最高温度约1100 K，加热830 K / s，冷却速率170 K / s和约3 s的总反应时间是γ-FeNi合金粉末优化溶胶-凝胶燃烧合成的特征。提出并通过配位金属-HMTA配合物形成合金的机理，并进行了实验验证。还研究和讨论了合成材料的微观结构和磁性。