影响共电沉积过程中纳米Cr、Al粒子复合量因素初探

FACTORS CAUSING DIFFERENT CODEPOSITION CONTENTS OF Cr AND Al NANOPARTICLES DURING Ni ELECTRODEPOSITION

在Ni与纳米Cr粒子或Al粒子共电沉积过程中,发现Ni镀层复合纳米Al粒子要比复合纳米Cr粒子容易.电化学测试表明:两种粒子在镀液中阴极极化行为不同,加入纳米Cr粒子后,极化曲线正向偏移,阴极极化降低.而加入纳米Al粒子后,极化曲线负向偏移,阴极极化增大.进一步用HREM对镀层中纳米粒子进行原子尺度观测,发现两者表面皆存在几个纳米厚的氧化膜层,提出了纳米粒子表面氧化膜半导体类型不同而引起粒子在镀液中吸附阳离子能力的强弱不同,是影响纳米粒子复合量的重要因素.

It was found that Al nanoparticles were easier to be codeposited than Cr nanoparticles during co - electrodeposition of nickel with nanoparticles of Al or Cr. The cathodic polarization test shows that the codeposition of Ni-Cr nanoparticles reduced the cathodic polarization, however, a reverse result was obtained during the codeposition of Ni-Al nanoparticles. HREM investigation indicated the existance of a 3 - 5 nm Cr2O3 or Al2O3 film on the surface of Cr and Al particles respectively. It is proposed that the Cr2O3 film is a p - type semiconductor, which exhibits a weak adsorption of cations during codeposition, while the Al2O3 film is a n - type semiconductor, which has a strong adsorption of cations of nickel and hydrogen. The different adsorption ability of the two oxide films formed is the primary factor causing the various codeposition contents of Cr and Al nanoparticles.