The effects of the pretreatment process on the microstructure and coercive force of electroless Co-Ni-P alloy films deposited on PET substrates are examined
The results obtained are as follows.
1) Pretreatment conditions affected the induction time of plating, but did not affect the deposition rate
2) The grain size of the deposited Co-Ni-P films was affected by the activating time and by the concentration of the activator solution The grain size increased with a decrease in activating time.
3) The coercive force of the deposited film exhibited the maximum value (12×10⁴A/m) when the activating time was 5s

View full abstract

Electroless plating of Pd-P alloys from palladium-ethylenediamine complex solutions containing sodium phosphite as a reducing agent was investigated. The deposition process proceeded autocatalytically, as in the case using hypophosphite, but the phosphorus content of the deposits was much lower. The phosphorus content of the deposits increased with an increase in phosphite concentration.
In as-plated deposits with only a trace of phosphorus, X-ray diffraction data showed a crystalline structure, but with an increase in phosphorus content, the structure became microcrystalline. As-plated deposits containing 3.74wt% phosphorus showed a very diffused diffraction pattern, changing into sharp crystalline features of Pd and Pd₆P after heat-treatment at 300°C.
About 60∼80 per cent of consumed phosphite was utilized for alloy deposition, and the mechanism of this can be well explained by Van den Meerakker's proposal.

View full abstract

TiN films were deposited under various conditions onto SUS304 stainless steel substrates by a hollow cathode discharge (HCD) type ion plating process. The corrosion resistance of the TiN-coated specimens in the active region was estimated in aqueous solutions of sulfuric acid, mainly by an electrochemical method. Measurements of the anodic polarization curves showed that the critical current density for passivation of the TiN-coated specimens was smaller than that for specimens without a TiN coating, that is, that active dissolution was retarded by TiN coating. The cathodic reaction tended to be similarly retarded by TiN coating. The corrosion resistance of the TiN-coated specimens was further improved by Ti undercoating and TiC coating under the TiN coating layer. This is attributed to the fact that the Ti undercoating and TiC coating decreased the number of defects that penetrate through the coating layers to the stainless steel substrate, that is, increased the intercepting effect of the coating layers from its surroundings. The intercepting effect of the coating layer from the surroundings of the specimens treated at 300°C was superior to that of the specimens treated at 450°C. The effect of hydrogen on the crack morphology of the TiN films was remarkable, and in the case of TiN films put into a hydrogen surroundings, cleavage fractures occurred.

View full abstract

The contact resistance between silicon and evaporated AuGeSb/Cr/NiCr/Ni films was measured, along with the mechanical strength of thess contacts and the effect on contact resistance and mechanical strength of the presence of an AuGeSb layer between the silicon and the Cr/NiCr/Ni layer.
These films were applied to the collector electrodes of power transistors and good reliability was obtained.

View full abstract

The dendritic migration of copper on taped lead frames is reproduced experimentally by dipping paird lead samples in pure water (0.8MΩ, 20±3°C) and subjecting them to a DC current of about 100μA.
We found several effects of alloying elements and heat treatments for samples on migration. This migration model mechanism was suggested by investigating the microscopic structure of migration dendrites and analysing other supposable factors.

View full abstract