The influence of burnishing on surface texture of regenerative NIAL-15%AL2O3 plasma sprayed coatings

The purpose of this study was the selection of roller- burnishing parameters of surface Ni-Al-15%Al2O3 composite coatings obtained by "PN 120" plasma torch. Coatings with low surface roughness could be applied as layers increase the service life of torque pumps shaft used on vessels in the sea water systems. After turning, the average surface roughness of plasma sprayed Ni-5%Al-15%Al2O3 coatings was Ra = 1.06 mikro-m. Their average hardness was equal to the 272 HV 2. After pre-treatment, plasma sprayed Ni-Al- 15%Al2O3 coatings were burnishing. Burnishing parameters were as follows: Vn=28,26 m/min, Fn=700N, fn=0,044 m/rev. Burnishing reduces the surface roughness of coatings as compared to machining. After the plastic working, the Ra parameter was reduced to a value of 0.77 m. Total height of waviness profile of machined coatings was 6.23 m. After burnishing, the value of Wt decreased by 0.22 m, to the value of 6.01 m. Studies burnished surface topography of coatings of Ni-5% Al15%Al2O3 overlaid by "PN 120" torch revealed the presence of defects stereometric structure. There are the spalling. After plastic working of plasma coatings, decrease of parameters of the material ratio curve values were observed. For example, the reduced peak height of cut coatings were 1.11 m, after burnishing Rpk value fell to 0.64 mikrom.