Micron-scale shielding: A magnetron sputtering approach for enhancing the fire safety of wood

This article investigated impact of ultra-thin layer of copper (Cu) and copper (II) oxide (CuO) on the fire performance of the Black poplar ( Populus nigra L.) wood. The ultra-thin layer of Cu (approx. 1.2 μm thin and mass per unit area 10.7 g⋅m -2 ) and CuO (approx. 1.2 μm thin and mass per unit area 7.6 g·m -2 ) was separately sputtered on poplar wood by magnetron sputtering device. The fire risk has been evaluated by a cone calorimeter (at heat flux 50 kW·m -2 ). The results proved that the micrometric layer of CuO has virtually no effect on fire hazard of poplar wood; expect of carbon monoxide (CO) yield which was reduced ca. by 25%. On the other hand the micrometric layer of Cu increased time to ignition (TTI by almost 200%), time to reach of maximum heat release rate (tHRR max by approx. 75%) compared to the uncoated wood, and at the same time reduced maximum average rate of heat emission (MARHE by almost 45%), CO yield (both per released heat and per mass loss by approx. 25% to 30%, respectively) and total heat release (THR by approx. 15%).