Journal Article•
Structural Transformations in electroless Ni-P-B deposits
01 Jan 1994-Plating and Surface Finishing (American Electroplaters and Surface Finishers Society)-Vol. 81, Iss: 5, pp 96-100
TL;DR: In this paper, a mixture of microcrystalline nickel and amorphous phases was observed to be a mixture based on X-ray diffraction and transmission electron microscopy.
Abstract: Electroless Ni-P-B deposits with weight percentages of 0.72 P and 4.15 B; 1.87 P and 4.87 B, were observed to be a mixture of microcrystalline nickel and amorphous phases, based on X-ray diffraction and transmission electron microscopy. On annealing, Ni 3 P and Ni 3 B precipitated along with crystalline nickel in one step. The microhardness of the deposits showed typical precipitation hardening behavior, with hardness increasing from about 550 VHN in the as-deposited condition, to about 1000 VHN in the fully crystallized condition
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TL;DR: In this article, the effect of heat treatment, particle size and phosphorus content on the wear characteristics of composite electroless coating containing diamond particles was investigated and the results indicated substantial increase in wear resistance after the coated sample containing 9-10 wt% P content having fine diamond particle size is annealed around 350°C.
103 citations
TL;DR: In this paper, the effect of process parameters such as stabilizer concentrations and plating bath temperature of the electroless Ni-P on efficiency and crystallinity are investigated, and the integral breadth, crystallite size, microstrain and the relative proportions of amorphous and crystalline phases present in the coating are obtained using the X-ray diffraction technique.
59 citations
TL;DR: In this paper, an alternative coating technique by r.f. magnetron sputtering is applied to deposit Ni-Cu-P coatings to solve the problem of composition control in the conventional chemical solution method.
Abstract: Electroless nickel is widely used as a hard coating for many industrial applications due to its extreme hardness, uniform thickness, corrosion and wear resistance. For advanced industrial applications, it is essential to promote the crystallization temperature of Ni–P deposits. In this study, Cu is introduced in Ni–P to improve its thermal stability. An alternative coating technique by r.f. magnetron sputtering is applied to deposit Ni–Cu–P coatings to solve the problem of composition control in the conventional chemical solution method. The Ni–Cu–P coatings were deposited by r.f. magnetron sputtering on 420 tool steel substrates with Cu+Ni–P compound targets. A novel design of compound targets with Cu and Ni–P by consideration of the surface ratio of constituents exhibits a controllable composition in the deposited film. The compositions of the Ni–Cu–P coating can be modified by the original Ni–P deposits of the compound target along with the Cu area ratio in the compound target. The planar uniformity of the compositions of the as-deposited Ni-Cu–P films is also achieved. All the as-sputtered (70.18–82.26 at.%)Ni–(17.17–1.39 at.%)Cu–(12.65–16.35 at.%)P deposits reveal an amorphous structure. The hardness of as-deposited Ni–Cu–P coatings decreases with increasing Cu content. Nevertheless, the hardness of the Ni–Cu–P films is still greater than that of the substrate. After annealing, the structure of the amorphous Ni–Cu–P deposits will transform directly into the Ni–Cu alloy and the Ni3P phase. The as-deposited Ni–Cu–P films can be hardened by precipitation of the Ni3P phase and crystallization of Ni–Cu. The introduction of Cu into the ternary Ni–Cu–P deposits increases the crystallization temperature as compared with the binary Ni–P film. The annealing temperature associated with the occurrence of the peak hardness in the (82.26 at.%)Ni–(1.39 at.%)Cu–(16.35 at.%)P and (74.27 at.%)Ni–(12.65 at.%)Cu–(13.08 at.%)P films is approximately 365 and 380°C, respectively. It is shown that the thermal stability of the Ni–Cu–P films is enhanced by increasing the Cu content in the sputtered deposits.
23 citations
TL;DR: In this paper, the effects of temperature, pH, and time variations on the protective amount and quality of electroless nickel (EN) deposition on cast aluminium alloy (CAA) substrates were studied.
Abstract: The effects of temperature, pH, and time variations on the protective amount and quality of electroless nickel (EN) deposition on cast aluminium alloy (CAA) substrates were studied. The temperature, pH, and plating time were varied while the surface condition of the substrate was kept constant in acid or alkaline bath. Within solution pH of 5.0–5.5 range, the best quality is obtained in acid solution pH of 5.2. At lower pH (5.0–5.1), good adhesion characterised the EN deposition. Within the range of plating solution pH of 7.0 to 11.5, the highest quantity and quality of EN deposition are obtained on CAA substrate in solution pH of 10.5. It is characterised with few pores and discontinuous metallic EN film. The quantity of EN deposition is time dependent, whereas the adhesion and brightness are not time controlled. The best fit models were developed from the trends of result data obtained from the experiments. The surface morphologies and the chemical composition of the coating were studied using the Jeol JSM-7600F field emission scanning electron microscope.
4 citations
Cites background from "Structural Transformations in elect..."
...The ease of simultaneous deposition particulate matters within a matrix of EN has given birth to the discovery and the development of new composite coatings, which can be made with crystalline and/or amorphous structure having a wide range of compositions [5, 6]....
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Journal Article•
TL;DR: In this article, the authors gratefully acknowledge Professor B.W.Mao for use of AFM facilities at her laboratory, and they would also like to thank J.Tang for assistance with AFM measurements.
Abstract: Acknowledgments The authors gratefully acknowledge Professor B.W.Mao for use of AFM facilities at her laboratory. We would also like to thank J.Tang for assistance with AFM measurements.
2 citations