A study of wear resistance of plasma-sprayed and laser-remelted coatings on aluminium alloy

Two kinds of alloys Ni–Cr–B–Si and Ni–Cr–B–Si+WC were plasma sprayed onto aluminium alloy. The coatings were remelted successively with a CO2 laser. A comparison of the wear resistance properties of both laser-treated and plasma-sprayed samples with those of aluminium alloy was conducted. A scanning electron microscope (SEM) was used to analyse wear phenomena of samples. Experimental results showed that the laser-treated and plasma-sprayed samples demonstrated, in general, good wear resistance. The laser remelted Ni–Cr–B–Si sample exhibited the highest wear resistance, and the laser remelted samples were much better than the as-sprayed samples. The plasma-sprayed Ni–Cr–B–Si+WC sample had better wear resistance than the sample without WC. However, the laser-treated Ni–Cr–B–Si+WC sample did not enhance its wear resistance compared with laser-treated Ni–Cr–B–Si sample. The worn surface analysis showed that the alloyed layer of the laser-treated samples was very compact, the worn surface was smooth and granular peeling was hardly observed. The worn surface of the plasma-sprayed sample was rather loose and there was granular peeling on the worn surface.