Boronizing of steel and iron to improve surface properties has been known for more than 50 years. Methods of boronizing have always been popular topics for research and development, which has resulted in a number of different techniques ranging from salt bath boronizing via pack boronizing to gas boronizing. Salt bath boronizing and gas boronizing are associated with certain toxic reactants and explosive nature. Consequently, only pack boronizing has been used commercially. However, this technique requires a lot of manual work with higher cost, which prevents it becoming a widespread technique. More recent plasma paste boronizing and boronizing paste have been developed, but the use of protective gas is still needed.

In the present work, a self-protective boronizing paste that can be used in any heating furnace without protective atmosphere has been developed. The characteristics of the paste, the microstructure of boronized steel and iron samples have been examined.