The ferrosilicon nitride starts with Si3N4 as its base component. It is accompanied by iron and unnitrogenized ferrosilicon among other additional materials. Ferrosilicon nitride powder used for fire resistance is a white or brown powder. Ferrosilicon nitride powder for steel production use comes in off-white granules.
Powdered ferrosilicon nitride is most commonly used as a stemming agent in large blast furnaces. It can also be used as an iron runner or other monolithic refractory applications. As quality requirements increase across the board for refractory materials, ferrosilicon carbide or silicon nitride has been used more as they offer increased heat resistance and hardness in refractory material manufacturing. They also reduce costs.
Granular silicon nitride is mainly used for oriented silicon steel or other steels that are strengthened by nitrides (such as HRB400 rebar).