This study investigates the morphological behavior of FeB and Fe2B phase in boronized 304 stainless steel under two different mediums which is powder and paste. Surface attrition was implemented in order to initiate better boron diffusivity. The comparison of microstructure in term of grain size and boride layer thickness were also analyzed. Scanning electron microscopy, X-Ray diffraction analysis and energy dispersive X-Ray Analysis were conducted to prove the existence of FeB and Fe2B phases. The relationship between the phase and Vickers microhardness was also investigated. The results show formation of flat-toothed boride layer in both sample with different FeB and Fe2B layer uniformity. Paste boronized sample with120 μm boride layer thickness had outperformed the powder boronized sample that with 43 μm boride layer thickness, thus providing significant improvement in microhardness values from 1500 Hv to 1800 Hv. In conclusion, paste medium provide outstanding boride layer thickness with 300% enhancement and excellent microhardness with 20% improvement. The results of this findings could offer a new insight in pack boronizing of stainless steel that can be complicated to boronized due to its high alloying element content.