| 摘要 |
Prepn. is carried out in two stages (I) applying an electroless coating to an activated insulating substrate using a soln contng. (a) hypophosphite, (b) a Ni salt, (c) EDTA or one of its salts, (d) pyrophosphate and (e) an orthophosphate; (2) stabilizing the layer resistance thus obtained by heating. The conc. of (c) is 0-0.09 g mole/1 and that of (a), (b), (d) and (e) sufficient to obtain by dissociation into ions, 0.15-0.3 g ions/1 hypophosphite. 0.01-0,1 g ions/1 Ni, pyrophosphate 5-15 times the difference between the concn. of the metal and of(c), and 0.01-0.06 g ions/1 orthophosphate, any cpd. of (c) being at least 0.005 g mole/1 smaller than l g ion/1 Ni. Pref. (c) is used at a conc. of 0.005-0.09 g mole/1. The pH of the soln is 5-7 and is used at a temp of 40-90 degrees C. |
