绿斑本质的分析研究

Analysis of green spot's nature

目的:绿斑的本质难以揭示,普遍认为钎料是绿斑形成的根源,但相悖于其成因之理,它不溶于水。条件:试制生物小试样的条件因陋就简,采用空气炉中冶炼的合金雾化的金属小球和最简单的钎焊模式。分析:抓住绿斑的特性,即绿色小斑点有腐蚀性,根据金属小球中有黑色细小颗粒炉渣,在钎焊温度下,对熔化的Ni基粉末钎料其表面上微小区域中发生偏析的纯Ni产生化学反应的结果,生成NiCl2。植入术后形成NiCl2·6H2O,是绿斑形成的机制。只要工艺措施予以改变,绿斑就会永远消失。结论:使用粉末Ni基钎料+金属小球中夹杂氯化物小而黑的炉渣会产生绿斑,其他任何的条件下不会产生绿斑。

OBJECTIVE： The nature of green spot is difficult to reveal, it is generally believed that a source of the spot formed by brazing metal, but it is injustice, it cannot dissolve in water. CONDITIONS： Because conditions for making small biological test samples were simply and thrifty, we used small metal ball which was atomized in air-furnace and the most basic brazing process. ANALYSIS： One of the characters of green spot was corrosive. According to study concerning small particles of black furnace slag in the small metal ball, in the brazing temperature, the pure Ni segregation occurred in micro-regions of molten Ni-based brazing powder surface. The pure Ni had a chemical reaction to generate NiCl2, after implantation that will produce NiCl2-6H2O. That was the mechanism of green spot forming. As long as the process measures were changed, green spot would go forever. CONCLUSION： Using the powder Ni-based filler metal ＋ the small metal ball, small and black furnace slag mixed with chloride will cause green spots. The spots will not appear under any other conditions.