It is prohibited to eat or drink from vessels made of silver or gold, and likewise, gold ornaments are forbidden for men because they involve arrogance and luxury. However, the sword is a symbol of striving and even self-sacrifice. If it has a small amount of gold or silver on it, there is no harm. Jihad is far removed from luxury; therefore, it is permissible to adorn the sword with gold or silver, provided that the gold is in the form of small, segmented markings and not in large quantity. The details have already been discussed previously. See: (Hadith: 5152)
Source: Sunan Nasa'i: Translation and Benefits by Shaykh Hafiz Muhammad Amin Hafizullah, Page: 5375