Optimisation of a Bath for Electroless Plating and Its Use for the Production of Nickel-Phosphorus-Silicon Carbide Coatings

YSZ Reinforced Ni-P Composite by Electroless Nickel Co-Deposition

“…In Ni-P-B4C EN system, particle composition in the matrix increased from 12 to 33 vol.% as the particle loading increased from 1 to 8 g/l (Vaghefi, Saatchi et al 2003). It was found that a particle loading more of than 15 g/l SiC in hypophosphite-reduced solution caused extensive bath foaming which reduced the plating rate (Kalantary, Holbrook et al 1993). …”

“…The addition of silicon carbide (SiC) powders with particle size ranging from 4-7 µm in varying EN solution conditions (composition, pH, temperature and time) showed an increase in SiC loading in the deposition but a reduction of the deposition rate and deposition weight (Kalantary, Holbrook et al 1993). Another study showed that co-deposition of SiC (1-5 µm) in sodium hypophosphite-reduced EN solution at pH 4.5-5.5, 80-90 o C with air agitation resulted in 25-30 vol.% SiC in the deposition (Li 1997).…”

“…In a study by Sheela & Pushpavanam (2002) on diamond EN co-deposition in hypophosphite-reduced solution showed that a vertical substrate position gave less than 20% particle incorporation compared to the horizontal position. Another study on Ni-P-SiC using hypophosphite-reduced solution with a particle loading of 25 g/l showed that the substrate held tangentially gave the highest particle composition in the matrix and a vertical position leading to uniform particle incorporation and adherence provided, that uniform agitation was used (Kalantary et al 1993). …”

“…A study showed that the structural characteristics and phase transformation of EN co-deposition incorporating Si3N4, CeO2 and TiO2 remained unchanged as from those of the conventional EN deposition. In general, various factors have been shown to affect the deposition of EN composites, including (1) particle catalytic inertness, (2) particle charge, (3) EN bath composition, (4) bath reactivity, (5) particle compatibility with the matrix, (6) plating rate, and (7) particle size distribution (Feldstein 1990 (Dai, Liu et al 2009); (Das, Limaye et al 2007) Silicon carbide SiC (Berkh, Eskin et al March 1996); (Kalantary, Holbrook et al 1993); (Lin, Chen et al 2006 Particle stability in this case could be the charge stability of the particles in the solutions. Particle stability determines the particle dispersion in the solution and particles' tendency for agglomeration or sendimentation.…”

“…Another study showed that co-deposition of SiC (1-5 µm) in sodium hypophosphite-reduced EN solution at pH 4.5-5.5, 80-90 o C with air agitation resulted in 25-30 vol.% SiC in the deposition (Li 1997). Aggressive agitation might cause substrate or deposition abrasion by other factors such as particle hardness, particle shape and size, particle loading and bath movement (Kalantary, Holbrook et al 1993). …”