Papers by Keyword: Electroless

Abstract: Electroless Synthesis of Nicle phosphate zirconium dioxide (EL NiP/-ZrO2) has been carried out with ZrO2 nanocomposite (50 to 160 nm and concentration 4 gpl) and randomly dispersed into an alkaline Ni-P electroless bath (pH 8.0). The deposited thickness of NiP/-ZrO₂ nanocoatings resting on mild steels (MS) substrate (AISI 1040 grade) is carried out to evaluate the surface morphology and elemental composition. The SEM, EDAX and XRD methods elucidated clear difference between Ni-P along with NiP/-ZrO₂ nanocomposite coatings. Moreover NiP/-ZrO₂ nanocoatings contain uniform burly of ZrO₂ nanoparticles like whitish globules. Further the as-coated Ni-P/-ZrO₂ nanocoatings revealed mostly amorphous structures, while in heated coatings (temperatures 150, 350, and 550 °C with pure Ar) as temperature rises, the amorphous structure transformed leisurely to crystalline structure. The microhardness values in Vickers-unit of the developed nanocomposite coatings are determined and it is found that for a particular load with increase of temperature microhardness as well as corrosion resistancealso increases. Keywords: Electroless; Corrosion; Ni-P/-ZrO2; nanocoatings; Microhardness

Abstract: Weight reduction in automotive and aerospace components can improve energy efficiency, reduce emissions, and increase performance. The adoption of light metals such as aluminium, magnesium and titanium alloys, is essential to these performance improvements; however, these alloys require protective surface coatings to prevent corrosion and resulting mechanical failures during service life. Traditional protective coatings for light-weight materials can be costly in terms of energy, raw materials, and environmental sustainability. New durable coating approaches are required to allow light-weight materials to be fully exploited in high performance applications. Novel Cirrus HybridTM coatings, a recent innovation in surface finishing, can protect a wide range of light metal alloy components using a sustainable, non-toxic process. Cirrus HybridTM coating technology deposits a thin-film, inorganic coating that bonds tightly to the light-metal alloy substrate. The process is energy efficient, does not rely on hazardous chemicals, and is up to 5 times thinner than traditional coatings for light metals. A Cirrus HybridTM coating provides excellent anti-corrosion, scratch, and wear properties, along with superior tribological, electrical, and optical performance. This paper updates the art of these innovative new coating technologies for reducing weight in industrial components without compromising functionality or performance.

Abstract: In this research work an effort has been made to study the tensile behavior of boron carbide and copper coated short basalt fiber reinforced with Al2014 based hybrid composites are prepared by stir casting technique. To avoid the interfacial reactions between basalt fiber and matrix Al2014 alloy the fibers are coated with copper using copper sulphate solution by electroless deposition method.The coated fiber was observed by scanning electron microscopy (SEM). It has been clearly revealed the uniform deposition of copper on the surface of fiber and tensile behavior of Hybrid composites was increased with increase in the wt% of reinforcements. At 6% boron carbide and 8% copper coated basalt fiber shows maximum tensile property.

Abstract: In this study, hardness and wear resistance of electroless Ni–P and Ni–P/Al₂O₃ composite coating have been investigated. These composite coatings are applied on iron substrate by electroless deposition process and then they were heat treated at 400°C for 1h. Surface and cross-section morphology of composite deposits have been investigated by scanning electron microscopy (SEM) and microstructural changes were evaluated by X-ray diffraction (XRD) analysis. The results showed that the Al₂O₃ particles co-deposited in Ni–P matrix led to an increase in the hardness and improve wear resistance, especially when the heat treated at 400°C will have the maximum hardness and wear resistance.

Abstract: The Ni-P coatings on steel strips were obtained by electroless method. Experiments were performed at three pHs, respectively: 6.6; 5.11 and 4.32 with immersion times 5 and 12 minutes at 80 - 85°C. Deposits were caractherized by energy-dispersive analysis (EDS), scanning electron microscopy (SEM) and optical microscopy. The chemical composition shows an increased of phosphorus content at the pH descrease, so at the pH-6.6 the phosphorus content in the coating is 4.74 wt% and at pH-4.32 is 12.42 wt% P. Regardless of the pH value is observed was some chemical dishomogeneity of layers the more pronounced with as the pH value is higher. Alongside Ni and P the layers can contain small amounts of oxygen and other elements coming from the nickel bath impurities and from working environment. Also it shows the surface morphology in correlation with the deposition process parameters and surface defects possible.

Abstract: This work presents investigations on preparation of 20 wt. % Pt_0.5Pd_0.5/C nanoelectrocatalysts by electroless and their electrocatalytic properties. The 20 wt. % Pt_0.5Pd_0.5/C nanoelectrocatalysts were prepared by electroless successfully. The optimum experimental conditions of the main effect factors in preparing the PtPd nanoelectrocatalysts are [Pt²⁺ or Pd²⁺] =2-10g/L, [HCHO] =10-20g/L, temperature: 40-60°C, the dosage of protection reagent: 1-3 % of the platinum and palladium content, the agitation rate 400-500r/min. The characterization of 20 wt. % Pt_0.5Pd_0.5/C was performed with cyclic voltammetry (CV) and transmission electron microscope (TEM), respectively. Particles of PtPd are distributed symmetrically on C by TEM, of which are very small and the average granularity is less than 3nm. The nanoelectrocatalysts have high stabilization and lots of catalysis nuclei through CV.

Abstract: In this paper, synthesis characterization and testing of hybrid polymer composite reinforced with electroless coated glass fiber is reported. The poly vinyl ester based composite is prepared with Electroless nickel phosphorus (Ni-P) coated glass fiber as the reinforcement. The glass fiber is coated with Ni-P by electroless plating method. The electroless Ni-P coating increases coating uniformity which in turn significantly improves properties such as hardness, strength and wear resistance of the glass fiber. Nano additives (0.5 wt.%) such as iron oxide, titanium oxide, copper oxide, aluminum oxide and zinc oxide are added into the matrix as fillers. The influence of different Nano fillers and its effect on the mechanical properties are examined. The result showed that after adding different nano particles, TiO₂ exhibited better properties when compared to composites with other nano additives. The experimental results showed that after Ni-P coating on the glass fiber, the ultimate tensile strength and compressive strength improved by 18% and 10% respectively and TiO₂ added PMC with 63%, 25% and 5% respectively.

Abstract: Electroless Ni deposition is often used in presence of Cu, Ti and Au. Recently TiW has also started to be employed, but with this alloy the Ni deposition is not always neat. In our work we investigate the effect of different wet treatments on the Ni growth by means of XPS analyses and SEM inspections. It is found that an oxidized surface inhibits the activator deposition. The de-oxidized Ti atoms in TiW on the other hand are believed to act as the principal sites for Pd seed deposition and subsequent Ni growth.

Abstract: In this research, micro-hardness and wear resistance of two types of electroless coatings were investigated including Ni-P and Ni-P-B₄C composite coatings. Dispersible B₄C particles and electroless Ni-P alloy were codeposited on carbon steel by electroless plating and then heat treated at 200, 400 and 600 °C for 1 h, respectively. The cross-section morphology and microstructure of the composite coatings were characterized. Meanwhile, the micro-hardness and tribological behavior of composite coatings were evaluated. The results showed that the Ni-P-B₄C composite coating presents better wear resistance in comparison with that of Ni-P coating. The Ni-P-B₄C composite coating with heat treated at 400 °C exhibits high micro-hardness and good wear resistance, which the highest hardness is 1200 HV, the minimum wear weight loss is 0.12 mg and the lowest friction coefficient is 0.2054.

Abstract: Ni deposited Hydroxyapatite powder was prepared by electroless deposition technique without sensitization and activation treatments. The composition and phase of deposition were studied. The surface morphologies and composition of initial pure HA powder, as received Ni deposited HA powder and compacted Ni deposited HA powder after sintering were characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) respectively. The phases in the powder before and after sintering were investigated by x-ray diffraction (XRD). From the experiment, with the increase of reduction agent, the plating time becomes shorter and optimal concentration of reduction agent and powder ratio is 3:1. The result shows that Ni succesfully deposited on HA powder and confirmed by EDX result. The Ni grain size distribution of 75nm to 250nm can be clearly observed on the HA surface from the micrograph after sintering. Decomposition of hydroxyapatite into α-TCP (α tricalcium phosphate) and TTCP (tetracalcium phosphate) did not occur in nickel deposited HA before and after sintering. On the other hand, a sharp Ni peak were detected