Auto-ignited hydrogen combustor using NaBH4 thermal decomposition for ignition of aluminum powders was described. The NaBH4 was thermally decomposed at 500 degrees C to generate hydrogen, and immediately the hydrogen was ignited because its auto-ignition temperature was 500 degrees C. The solid grain of NaBH4 was prepared in a hollow shape and the air was supplied as an oxidizer for hydrogen auto-ignition. The effect of the air supply rate on the characteristics of the NaBH4 thermal decomposition was evaluated. As a result, the decomposition efficiency was 95% and hydrogen flame was retained for 110 s with 30 g of NaBH4. When the hydrogen flame was stabilized, aluminum powders was injected into the combustion zone with 1.268 g/min using the powder injector. The ignition of aluminum powders was successfully performed by the hydrogen combustor using the NaBH4 thermal decomposition. The combustion of aluminum powders was validated by a photodetector equipped with a 486 nm filter for A10 radical detection. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.