The effect of deposition temperature on the surface coverage and morphology of iron-phosphate coatings on low carbon steel

► The influence of temperature and concentration of NaNO2 in iron-phosphating bath was investigated. ► The increase in temperature of the NaNO2-free bath up to 70 °C caused increase in surface coverage. ► The addition of NaNO2 increased surface coverage at temperatures lower than 50 °C. ► The increase of NaNO2 concentration decreased phosphate crystals size, favouring phosphate nucleation with better crystals packing. ► Phosphate crystals had laminated and needle-like structures.