Laser surface treatment of electroless Ni–P coatings on Al356 alloy

Laser surface modification of aluminium and magnesium alloys

“…this was attributed to the presence of elemental Ni; the fine Ni-Al intermetallic phases; and a Ni-rich aluminium solid solution in the surface layer. Razavi et al (2008) reported similar results, but indicated that if the electroless films are too thin or the traverse rate too low (and the interaction time consequently high), excessive alloying with Al occurrs, resulting in a reduced resistance to corrosion.…”

“…A hardness increase to 325 HV compared to 60-70 HV for the substrate was produced (Joshi and sundararajan, 1998). the use of Ni or Ni-based materials for alloying has been extensively investigated at least since the late 1980s (Kreutz et al, 1987;Jobez et al, 1989;shibata and Matsuyama, 1990), and interest in these has still not waned (Yang et al, 2005;Cui et al, 2008;Gordani et al, 2008;Razavi et al, 2008).…”

Ultrasonic irradiation assisted electroless Ni–P coating on magnesium alloy

“…It has been reported that the microstructure in the surface layer of metals and alloys could be refined to the nanometre level by means of surface mechanical attrition treatments such as milling, grinding and shot peening. 20,21 Here, cavitation induced streaming and microjetting, like mechanical attrition, can refine the Ni–P grains, slow down the growth of Ni–P grains and dislodge some loose Ni–P grains from the coating surface, leading to formation of thin but dense, fine and compact coating for the same deposition time as EP in static electrolyte. The effect of UI on the coating's ultimate thickness is the result of the above two opposing processes.…”

Study of Nd:YAG laser annealing of electroless Ni–P film on spiegel-iron plate by Taguchi method and grey system theory

“…Most of the electroless Ni-P films were annealed by conventional furnaces [9][10][11][12], and a few by laser [13][14][15]. In the conventional annealing process, the film and the substrate both are heated and cooled so that relatively much energy is needed and the interdiffusion and reaction between Ni-P film and substrate may take place.…”