Study on wear resistance of duplex surface treatment with laser cladding and active screen plasma

In order to study effects of laser cladding layer performance on wear resistance of active screen plasma treating nitride coating, two kinds of Fe-based alloy powders, Fe314 and Fe90, were adopted to laser clad on steel 45 substrate surface. And then the laser clads were duplex-treated by active screen plasma nitriding. Wear tests were carried out for the laser clads and duplex coatings with wear tester under dry sliding condition. Experimental results show that hardness of the Fe90 duplex coating was increased from 750HV of the Fe90 laser clad to 1350HV, and hardness of the Fe314 duplex coating was increased from 540HV of the Fe314 laser clad to 927HV. Under the same load (30N), wear resistance of the Fe90 duplex coating was 1.2 times of that of the Fe90 laser cladding layer. However, wear resistance of the Fe314 duplex coating was only 0.42 times of that of the Fe314 laser cladding layer. It can be found that the key problem for improving wear resistance of the duplex coating lies on reasonable combination of the laser cladding layer and active screen plasma treating nitride coating, the former should provide enough support for the latter.