Characterization of phase transformation behaviour and microstructural development of electroless Ni–B coating

Tribological behavior of electroless Ni–B–W coating at room and elevated temperatures

“…In the present work, though the B content decreases, the deposits are amorphous since the inclusion of W promotes the amorphous phase. 38 39 when the coatings were heat treated at 350 C and 450 C for 1 h. The apparition of Ni 3 B phases induced due to heat treatment of Ni-B coating has been also reported by Kanta et al, 40 Delaunois and Lienard 41 as well as Pal et al 20 Aydeniz et al 30 observed that electroless Ni-B-W coatings are amorphous in their as-deposited condition and precipitation of Ni, Ni 2 B, and Ni 3 B takes place on annealing though incorporation of W may lead to an increase in the crystallization temperature. 38 Therefore, phase transformation observed in the present work agrees well with various literature.…”

“…18 Generally, coatings with boron content between 5 and 6 wt% are observed to be amorphous. [18][19][20] Ni-B coatings containing 5% B exhibit a mixture of amorphous and nanocrystalline structure. 21 Similar results have been also reported by Balaraju et al 23 for coating consisting of 5.37 wt.% B.…”

“…38 Therefore, phase transformation observed in the present work agrees well with various literature. [17][18][19][20][21]40,41 Inter-metallic Ni-W phase is not observed, which indicates that the inclusion of W may assist in solid solution strengthening of the binary alloy. Similar behavior has been observed for electroless Ni-P-W coatings and the solid solution strengthening phenomenon lead to an improvement in the mechanical properties.…”

“…16 Although the tribological behavior of electroless Ni-P coatings and its variants are widely investigated, attention has been given now to sodium borohydride reduced Ni-B coating and its variants due to their high hardness and outstanding tribological properties in comparison with Ni-P coatings. 17,18 Heat treatment of Ni-B coatings [19][20][21] especially in vacuum 22 results in high improvement in the microhardness due to the precipitation of crystalline nickel and its hard boride phases. The typical cauliflower like surface morphology and columnar growths further aid to the improvement of tribological properties by imparting self-lubricating properties and reducing the actual area of contact.…”

Investigation of structural and tribological properties of electroless Ni–B coated pure titanium

“…Similar results were obtained in the literatures. [24][25][26] In their study, Anik et al 27 reported that the heat treatment applied over 380 C caused amorph Ni-B coating to be crystallised. When the structure provided via heat treatment is examined, it can be observed that it consists of CuAl 2 -y-type volume-centered tetragonal Ni 2 B and Fe 3 C cementite-type orthorhombic Ni 3 B phases.…”