Laser cladding of stainless steel on magnesium ZK60/SiC composite

Laser cladding of stainless steel on ZK60/SiC composite was achieved by usi ng a two-step method, i.e. thermal spray and laser re-melting. This was mad e possible by using interlayers of brass and copper, as a result, good meta llurgical bond interfaces were obtained. However, the rapid solidification condition caused liquid phase separation. As a consequence, small spheroids of copper-rich phase were formed in the stainless steel matrix, which are found to be detrimental to the corrosion resistance of the material. Noneth eless, the corrosion potential (E-corr) of the laser-cladded sample was 109 0 and 820 mV higher than that of the as-received and as-sprayed samples, re spectively, while the corrosion current (i(corr)) was some two and four ord ers of magnitude lower. The laser-cladded sample, like the untreated compos ite, did not show a passive region in the polarization plot. This is believ ed to be due to the segregation of copper-rich phase at interdendritic regi ons, and the presence of copper-rich spheroids in the stainless steel matri x. (C) 2001 Elsevier Science B.V. All rights reserved.