| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1658248 | Surface and Coatings Technology | 2012 | 6 Pages |
Black coatings have been widely used in industries for their excellent decorative, physical and mechanical properties. In this paper, a new blackening process of the NiWP deposits was reported. Uniform black coatings can been obtained by simply immersing the NiWP deposits with less than 26.35% (by weight) of W content in the HCl–H2O2–HF solution. The influence of tungsten content on blacking was discussed by comparing morphology and chemical composition of the NiWP deposits. The formation mechanism studies of black film showed that the black color of the NiWP deposit was caused by both its unique dense meshwork morphology at the surface of the NiWP black layer as well to the formation of oxides (NiO, Ni2O3 and WO3) and phosphate products (Ni(H2PO4)2). Optical property, thermal stability and corrosion resistance of the black ternary NiWP coatings were also studied in detail.
► Little work has been seen about the blackening of electrodeposited NiWP alloys. ► A new blackening process for NiWP alloys is reported. ► Uniform black films were fabricated by immersing NiWP deposits in HCl–H2O2–HF solution. ► The properties and forming mechanism of black film were studied. ► Formation of oxides and a dense array of meshwork are reasons for the black color.
