Abstract
Nanoparticles of nickel can be synthesized from NiCl2．6H2O by hydrazine in alkaline solution in the presence of polymers ( PVP or PAA ) served as protective and stabilizing agents. In addition, either palladium or NaBH4 was added to promote the chemical reduction of nickel ion. In this thesis, the reaction temperature was always kept constant at 80℃, and the nickel ion concentration at 0.01M. Regardless of the polymer ( PVP or PAA ), when palladium was used as a nucleator, the conversion of nickel ion was only about 30%, if we try to keep nickel particle size under 100 nm. However, if NaBH4 was added instead, the conversion of nickel ion increased to 80%. Comparing the protective capability to nickel nanoparticles, PAA is better than PVP. By adding different amount of NaBH4 to nickel ion solution, we could get different nickel nanopatricles which is named NP-R=0.125、NP-R=0.375、NP-R=1.25. When these nanoparticles were made into thick films, our data showed that the film resistivity would decrease with sintering temperature. After sintering at 500℃, the film made from NP-R=0.375 nanoparticles exhibits a resistivity of 7.13 mΩ-cm. The SEM pictures indicated that films with good sintering quality have lower resistivity. As a result, the resistivity of the film made from NP-R=1.25 nanoparticles is higher than another two because of poor sintering results. Finally the oxidation rate constant of nanosized nickel powder is about 5.32 ×10-15 cm2╱s at 280℃ and 5.64 ×10-15 cm2╱s at 300℃. After the phosphating process, nickel powder with 4.27% phosphorous atoms on its surface exhibited delayed oxidation for at least 20 min at 300℃.