The significance of process parameters in electroles Ni-P coating for fabrication of Ni-P/C-fibers precomposite
Jerzy Bieliński, Anna Broda, Rafał Kozera, Alicja Bielińska, Anna Boczkowska, Krzysztof J. Kurzydłowski
Quarterly No. 3, 2010 pages 206-212
DOI:
keywords: electroless Ni-P deposition, parameters of metallization of carbon fibers, MMCs precomposites
abstract The investigation of the electroless metallization of carbon fiber is presented here in aim to establish the significance of main process parameters steering the Ni-P alloy composition and deposition rate (thickness of coating). The role of bath composition (Ni-salt, reducer, complexing-buffering additive, stabilizer, wetting agent), pH value, temperature and deposition time, as well as kind of carbon fiber, were the object of investigation. The requirements for Ni-P/C-fiber/aluminum composite fabrication limited the P-content to 2÷3% and coating thickness to less then 1 μm. The metallization process, after proper carbon fiber pretreatment, was performed in baths containing: NiSO4, NaH2PO2, glycine, stabilizers and wetting agents. The pH was changed in range 4.5÷8.5, temperature 60÷80oC and deposition time from 5 to 60 min. As substrate for metallization the roving and fabric of Tenax produced carbon fibers (3÷24k filaments with 7 μm diameter), as well as mullite test samples was used. The results of experiments, at limited changes of pH in bath, indicated that the ratio of NiSO4/NaH2PO2 concentration is the main factor determining the P-content and the Ni-P deposition time is the best factor for fixing the coating thickness. The increase rate of Ni-P coating thickness depend also on the kind of carbon fiber roving.