## 3 Results and Discussion  
### Benchmark Study  
In the following, for all considered thermite couples, the initiation delay, temperature and burn rate are reported in Table 1, with some highlighted materials properties. We also consider a disruption temperature which is defined as the temperature limit above which the body of thermite material is dispersed away from its original state (position and structure). In other words, considering an open system, disruption causes the thermite to be dispersed into the environment. Therefore, at the disruption temperature, the energetic reaction of the system is stopped. This phenomenon has been introduced in a previous work on thermite nanolaminates [49]. The disruption temperature is assumed to match the lowest vaporization temperature of all materials present in the nanothermite (see Table 1). Overall, the best performances are obtained with aluminum as a fuel. Apart from iron oxide, which shows specific behavior across all fuels, aluminothermites (thermites with Al as fuel) are the only fuel group tested that can exhibit initiation delays below the 100 ms regime. Initiation temperatures are also the lowest, in the 900-1000 K range (with the exception of iron oxide). And finally, aluminothermites have high burn rates, notably for the CuO oxidizer, which obtains the highest burn rate of all tested cases (60 cm\(\cdot\)s\({}^{-1}\)). Thermite reactions can be primarily governed by the oxygen diffusivity through its oxidized fuel, the reaction product, which may act as a barrier for the reacting species to meet and react. Even though the oxidizer is usually chosen for its relative metastability, its decomposition or simply its ability to provide an easy pathway for migrating oxidizing species towards the fuel and its oxide may temper the role of the oxidized fuel barrier layer as the leading parameter, as we will see for most cases apart from CuO. Obviously, the thermal conductivity as well as the reaction enthalpy are other important parameters. This multiplicity of components makes it very difficult, if not impossible, to quantitatively predict a priori the reaction behavior of a given thermite. We will now discuss each considered thermite into more detail. _Aluminothermites_--Al/CuO is probably the most studied nanothermic couple in powder form, we have shown that under usual initiation conditions (10\({}^{5}\) K s\({}^{-1}\)) condensed phase mechanisms correctly match experimental results in term of initiation [5; 39]. For the present Al/CuO simulated experiment, the initiation delay, 91 ms at 943 K, is roughly one order of magnitude higher than in Reference [39], in the millisecond range, using similar nanoparticle sizes. Indeed, in that base model, all heat losses, both towards an adjacent cell for propagation and into the environment, were neglected. In this full propagation version, the model contains an explicit treatment of packing and losses due to conduction, convection, and radiation that slows down the temperature rise upon external heating and, consequently, the chemistry of initiation. The calculated steady state burn rate is established at 60 cm s\({}^{-1}\) (see Figure 3a). Calculations agree fairly well with the work by [PERSON] et al., where high-speed microscopy permitted in-operando observation of the propagation reaction on a local and macroscopic scale [36]. The authors distinguish a rapid (50 cm\(\cdot\)s\({}^{-1}\)) microscopic combustion process due to sintering within the flame front, i.e., a purely condensed phase process, from a much slower propagation regime, 3.3 cm\(\cdot\)s\({}^{-1}\), observed macroscopically. Interestingly, a simulation with parameters corresponding to their experimental setup, with a 85 nm fuel diameter, 98 nm oxide diameter, \(\zeta\) = 1.2, and an imposed conductivity of 0.1 W\(\cdot\)m\({}^{-1}\cdot\)K\({}^{-1}\), as determined by the authors, leads to a drop of the reaction propagation speed down to 8.5 cm\(\cdot\)s\({}^{-1}\), agreeing fairly well with the balance of micro versus macro burn rates.