Electroless Plating Method

In order to reduce the thermal mismatch between the Pd alloy film and the porous substrate, metal porous supports (stainless steel, nickel, etc.) are used with an intermediate layer to reduce the intermetallic diffusion (with consequent poisoning) between the metal porous support and the Pd/Ag layer. The intermediate layer can be a ceramic or a porous Pd/Ag layer prepared by the bi-metal multi-layer deposition technique [17]. The resulting membranes demonstrate high operating temperature (over 500°C) and long-term durability. 

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Previous studies focusing on deposition of Cu [6, 15] or Ni [16] coatings and deposits on natural and synthetic graphics relied on an electroless plating method [25]. In this method many different chemical solutions are used in multiple steps to treat the graphite surface, such as... 

The electroless plating method described above was used to prepare membranes that contain cylindrical gold nanotubules, which span the complete thickness of the membrane. As before, polycarbonate filtration membranes with cylindrical, monodisperse pores (Poretics, 6 [im thick, pore dia. = 30 nm) were used as the templates. The inside diameter (i.d.) of the nanotubules can be varied by varying the plating time (Fig. 14). At sufficiently long plating times, Au nanotubules with i.d.s of molecular dimensions (<1 nm) are obtained [106],... 

On the other hand, wet process metal coating method was applied to the surface-modified nylon 12 particles (24). Nylon 12 particles modified by alumina or silica fine particles were given metallic coating by an electroless plating method. 

PTFE composite plating by the electroless plating method excels in its workability for producing hard coatings. Accordingly, plating material manufacturers generally... 

Y. Harada, K. Fushimi, S. Madokoro, H. Sawai, and S. Ushio, The characterization of via-filling technology with electroless plating method, J. Electrochem. Soc. 133, 2428, 1986. 

Osaka T et al (1990) High density perpendicular recording media by an electroless plating method. ITEJ Tec Rep VIR90-29 l-9... 

The applications and the research studies performed on this kind of reaction were realized by many scientists. In particular, a great literature is present on this issue concerning the use of palladium-based membrane reactors, as resumed briefly in Table 2.7, where CO conversion values obtained in MR and compared with the thermodynamic equilibrium ones of some scientific works are reported. In particular, among these works, Kikuchi et al. [115] demonstrated that, using a 20 pm layer of palladium-coated onto a porous glass tube produced by the electroless plating method, allows to obtain almost complete CO conversion. 

A Fe-Co-B catalyst system on Ni foam was prepared by a modified electroless plating method. Hydrogen production rate of the system was foimd as 221 mL min g p at 30°C. Activation energy was calculated as 27 kj moTF The relatively higher catalytic activity of the catalyst is related with its porous microstructure. This enhanced the accessibility of reactants to catalyst active sites. Catalyst coating was 12.5 mg cm (Ni foam) and the composition was 56.4% Co, 38.8 wt.% Fe and 4.8 wt.% B. BET specific surface area of the catalyst system was 9.7 m g F Also in the study, it was claimed that the maximum reaction rate was not observed at the beginning of the reaction due to the pore diffusion resistance and hydrogen desorp-tion/absorption equilibrium in the catalyst was in need of time. The catalyst system lost 30% of its initial catalytic activity after 3 cycle and 46% after 6 cycle [23]. 

Co-B on Ni foam support catalyst system was produced by low temperature electroless plating method. With this approach, maximum hydrogen production rate of 24 L min g at 30°C was achieved. The catalyst system was mixture of spherical particles and a thin nanosheet-like structure of 10 nm. Layered aggregates of these nanosheet-like morphologies were seen as smooth spherical particles of size 2-10 pm. Co/B ratio in the catalyst coating was 3.67 according to EDX results and 1.45 according to XPS... 

Mukaida, M., Takahashi, N., Hisamatsu, K., Ishitsuka, M., Kara, S., Suda, H., et al. (2010). Preparation for defect-free self-supported Pd membranes by an electroless plating method. Journal of Membrane Science, 365(1), 378—381. 

Onodera T, Suzuki S, Takamori Y, Daimon H (2010) Improved methanol oxidation activity and stability of well-mixed PtRu catalysts synthesized by electroless plating method with addition of chelate ligands. Appl Catal A Gen 379 69-76... 

From the aforementioned materials, the noble metals (Pt, Au, or Pd) are usually a preferred choice for IPMC electrodes due to their high electrical conductivity and electrochemical stability and availability in cation complex form that can be effectively used with electroless plating method. 

Figure 4.7 SEM images of a composite Pd-ceramic membrane prepared by the electroless plating method (a) cross-section (b) palladium surface. Reproduced from [16]. With permission from Elsevier.

Although deposition of tin is also possible through immersion and electroless techniques, these deposition methods are not considered here for component finishing due to the relatively high thickness requirements (typically > 8 pm). Also, high productivity is required for component finishing which makes immersion and electroless plating methods not feasible for this application. 

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