A study on the microstructure and phase transformation of electroless nickel deposits

Effects of phosphorus content on the reaction of electroless Ni-P with Sn and crystallization of Ni-P

“…The microstructure of Ni-P is expected to vary depending on the P content: nanocrystalline for 4.6wt.%P, amorphous with some crystallites for 9wt.%P, and completely amorphous for 13 wt.%. [6][7][8][9][10] Differential scanning calorimetry (DSC) was used to study the interfacial reaction between Ni-P and Sn and the crystallization of Ni-P at a heating rate of 5°C/min in an N 2 atmosphere. Samples heated to 300°C and 450°C in the DSC were cooled down in air to room temperature, and the remaining Sn after the reaction was etched with 10vol.%HCl solution.…”

“…8 A transition point to an amorphous structure is not clear because Ni-P with 10.1wt.%P was reported to have 4-5-nm grains even though its electron diffraction pattern showed amorphous characteristics. 9 The crystallization temperature of a Ni-P film is also known to vary widely depending on P content: 300-450°C for 1.9-13.6wt.%P. [9][10][11] When a Ni-P film reacts with a Sn-Pb eutectic solder, some part of the film underneath the solder crystallizes into Ni 3 P (P-rich layer) around the reflow temperature (200-240°C).…”

“…9 The crystallization temperature of a Ni-P film is also known to vary widely depending on P content: 300-450°C for 1.9-13.6wt.%P. [9][10][11] When a Ni-P film reacts with a Sn-Pb eutectic solder, some part of the film underneath the solder crystallizes into Ni 3 P (P-rich layer) around the reflow temperature (200-240°C). This low-temperature reaction is called "solder reaction-assisted crystallization," 12 in contrast to the self-crystallization of Ni-P at a higher temperature.…”

Surface characterization of zincated aluminium and selected alloys at the early stage of the autocatalytic electroless nickel immersion process

“…Deposition with lower phosphorus concentration is characterized by the presence of crystalline and microcrystalline structure, which indicates that the number of phosphorus atoms is not sufficient to distort the nickel lattice. According to Agarwala and Agarwala [16] and Park and Lee [17], an increase in phosphorus content produces amorphous deposition due to the increase in lattice distortion caused by phosphorus atoms situated in the interstitial position of the nickel. It has been found that a number of crystalline non-equilibrium phases are present due to the compositional inhomogeneties prevailing in the Ni-P deposited layer.…”

Versatile algorithms for the computation of 2-point spatial correlations in quantifying material structure

“…Although a number of different measures of the spatial correlations in the microstructure are possible (e.g., lineal path functions [27][28][29][30] and radial distribution [30][31][32][33] functions), only the n-point spatial correlations (or n-point statistics) [15,16,18,19,30,[34][35][36][37][38][39] provide the most complete set of measures that are naturally organized by increasing amounts of structure information. For example, the most basic of the n-point statistics are the 1-point statistics, and they reflect the probability of finding a specific local state of interest at any randomly selected single point (or voxel) in the material structure.…”