The arc extinguishing capacity of the dc contactor should be better than that of the ac contactor. If arc extinguishing is not good, first check whether the travel of the moving contact of the contactor is normal.
Then check whether the controlled loop current is too large and the voltage is too high. If the current is too high or the voltage is too high, can replace the contactor.
There is also a situation where the contactor is used to cut off the large inductance loop. Because of the high self-sensing potential, it is also difficult to extinguish the arc.