Synthesis of electroless Ni-P/Ni-P-W nanocomposite platings and sustainable tribological characteristics
The tungsten (W) is an exceptionally strong refractory metal of group VIB of periodic table and has the highest melting point, the lowest coefficient of thermal expansion with high neutron capturing capability and can remove sulphur from crude oil. Therefore, considering environmental, corrosion and tribological applications the Ni-P/Ni-P-W nanocomposite depositings (Na2WO4, amount 0.5±0.01gpl and size 40-150 nanometer, pH=05.6, thicknesses from 03.2 to 14.7 micronmeter) were produced on mild steel (MS; AISI1040 grade) substrates as an alternate of hard chrome platings. The SEM, EDAX, and XRD instrumental studies illustrate that as-deposited Ni-P-W nanocoatings naked mostly amorphous structures, whereas into cases of heated depositings (temperatures 2000C, 4000C, and 6000C with uncontaminated Argon environment), the amorphous structure transformed leisurely to crystalline structure as the temperature get higher. Furthermore, the daintily created Ni-P/Ni-P-W depositings were tested for tribological applications using a wear tester (model TR-20LE-CHM-400; Ducom), and a Vicker microhardness tester (VMHT-MOT). The wear and microhardness tests were carried out in accordance with the ASTM G99 standard with varying loads and deviations over an invariable 250.0-meter distance (wear test). Consequently, the inclusion of tungsten (W) nanoparticles into the acidic electroless Ni-P matrix had a noteworthy impact on wear and microhardness resistance and can be effectively used as an alternate of hard chrome platings. The results can be arranged into the following manner: Ni-P-W (heated at 400°C) > Ni-P-W (heated at 600°C) > Ni-P-W (heated at 200°C) > Ni-P (heated at 400°C) > Ni-P (as-deposited) > MS.