Electroless metallization of α-alumina powders for preparation of low-phosphorus Al2O3/Ni-P composites
Jerzy Bieliński*, Alicja Bielińska*, Iwona Kulak*, Justyna Kuziak*,Jakub Michalski**, Katarzyna Konopka** *Politechnika Warszawska, Wydział Chemiczny, ul. Noakowskiego 3, 00-664 Warszawa **Politechnika Warszawska, Wydział Inżynierii Materiałowej, ul. Wołoska 141, 02-507 Warszawa
Quarterly No. 2, 2005 pages 52-57
DOI:
keywords:
abstract The investigation of the electroless metallization of alumina powders was presented in this work and namely from the low-phosphorus Ni-P deposition bath. So distinct reduction of P-content (even to 2÷3 wt.% range) allows the increase of the temperature in composite sintering process. The electroless metallization was carried on the alumina powders of α-Al2O3: Electro- corundum (grains 50÷75 μm) and corundum Martinswerk (1÷6 μm). The influence of the particular parameters of electroless metallization on the P-content in deposited Ni-P alloy coatings and on the metallic phase content in the Al2O3/Ni-P powder composite (rate of deposition) was determined. In investigated alkaline electroless nickel baths the concentration of Ni-salts, hyphophosphite, buffering/complexing compound (glycine), pH-value and temperature was the subject of changes. Statistical experiment design methods have been applied to characterize and compare the metallization process for different types of powders. The obtained Al2O3/Ni-P composite powders contained from 1 to over 20 wt.% of Ni-P and the P-content in Ni-P was in 2÷11 wt.% range. The possible role of parameters in composite deposition process have been discussed. The introductory structural and morphological characterization of the Ni-P coatings (ca 2% of P) and composite powders as well as sintered samples of Al2O3/Ni-P was carried on. Key words: electroless Ni-P deposition, powder substrates, Al2O3/Ni-P composites