Diffusion coatings are utilized on metallic surfaces to serve as protective layers to the substrate material. Typically the diffusion coatings are applied by surface penetration of the metal on nonmetal element at elevated temperatures into the substrate material.

This paper describes the recent investigation of microstructure and properties obtained on steel and some metallic alloys by surface modification with boron.

Optical microscopy examinations of the borides formed on the surface of metallic alloys revealed smooth homogeneous layers. The thickness of the boronized coatings was measured and it was observed that it depends on the process time, process temperature, and chemical composition of the substrate material. It was found that higher process temperature, and longer boronizing time result in an increase in the layer thickness.

The presence of borides was revealed by means of X-ray diffraction, Scanning Electron Microscopy, and Optical microscopy. In order to determine the distribution of boron and the alloying elements from the surface to the inner structure, Energy Dispersive Spectroscopy was used.The microhardness of the obtained diffusion coatings was measured, and the corrosion resistance was evaluated by measuring the weight loss with time.

The boronized samples showed improved corrosion resistance in various chemical environments, and exhibited increased microhardness.