Among all the spraying conditions investigated, conditions 9 and 10 have the highest coating porosities (see Supplementary Table S1). Note that when the total plasma flow rate was reduced, the total torch power also decreased. However, conditions 9 and 10 have similar torch power, slightly higher enthalpy, and the same standoff distances as conditions 1 and 3 respectively, but higher porosity. The high coating porosity resulting from the lower gas flow rate agrees with previous findings of solution precursor flame-sprayed coatings