Brown rust color instead of a black mark

Question- am getting a brown rust color instead of a black mark. Are the CerMark laser marking materials bad?

Answer- No, the marking materials are fine. The browning or rusting occurs when you have applied too much thermal energy either due to slow speed or excess power. In this case, you have actually burnt the CerMark material. To fix this you should increase the marking speed or lower the laser power.