From the simulation, the amounts and thereby the partial pressures of all species in the system where obtained. Figure shows how the partial pressures, relative to the initial pressure of ammonia, evolve during 100 s at 1000 °C, 10 mbar total pressure and an ammonia to carrier ratio of 1:10 in all investigated carrier gases. The simulation shows that at these conditions, ammonia is stable for a couple of seconds before any noticeable decomposition starts to occur in N2 and Ar ambients and after 100 s only about 20 % of ammonia has decomposed, Fig. . The simulations also show that using a carrier containing hydrogen gas, the decomposition decreases to almost zero. Less than 1 % of the ammonia has decomposed after 100 s in a pure hydrogen carrier gas. By comparing simulations at different temperatures, the temperature dependence for the ammonia decomposition could be studied. Figure in the supplementary material shows the decomposition at 700 °C, 10 mbar and 1:10 ammonia to carrier ratio. At these conditions, the decomposition is close to zero as seen by the almost unchanged pressures over the simulation time. Less than 2 ppm of the initial ammonia has decomposed in N2 or Ar carriers after 100 s and even less in H2 containing carriers.