對奈米材料的應用而言，表面改質是一重要技術。奈米微粒因其具有高表面能而展現獨特的性質，因此研究奈米科技的重點之一，即在於控制奈米材料表面的特性。藉由表面改質可以製造分散良好且少結塊的奈米粉，亦可增加奈米粉的實用性，製造出應用性強的材料，在生物、化學及物理領域的研究，佔有舉足輕重的角色。
本研究係以化學方法施覆一層保護劑，在粉末表面改質，選用微米銀粉、鎳粉、以及奈米鈀銀及矽晶粒，研究改質粉末的燒結現象，而改質後的奈米矽粉亦觀察其光激發光機制。

根據紅外光譜分析，在粉末表面施覆硬脂酸或聚乙二醇可有效改變其表面官能基。而熱分析的結果發現，改質鎳及鈀銀粉的氧化量較一般未改質粉為低。燒結曲線也顯示，保護劑對粉末的燒結有抑制的效果。改質粉末的燒結性質因為表面能的降低以及保護劑包覆粉末而異於原始粉末。奈米矽粉的光激發光光譜因保護劑之包覆，改變其發光機制而改變光譜峰。

Surface modification is an important technology for applications of nanomaterials. Because the high surface energy is a unique property of nanoparticles, one of the key nanotechnologies is to realize and control the surface properties of nanomaterials. With modification, nanoparticles can be better dispersed and agglomeration is reduced. They may be converted to be more useful and powerful materials. Nanomaterials find many new applications in chemical, biological, and physical fields.
In this study, surface modification was made by a chemical method to cover a layer of protective agent ( stearic acid or polyethylene glycol )on the particle surface. Four kinds of starting materials, Ag and Ni microcrystalline powders, and Pd70Ag30 and Si nanoparticles, were studied. The sintering properties of normal and modified particles were investigated, and the light emission characteristics of normal and modified Si particles were also compared.

According to the FTIR spectra, the modification process was efficient to coat a layer of stearic acid (SA) on the powder surface. From the thermogravimetric analysis, the oxidation of powders after surface modification was reduced. The sintering curves showed that the protective agents could effectively suppress the sintering. The sintering behaviors of modified powders were different from those of normal powders, because the surface energy was decreased and the powder surface was protected by the agents. The photolumescence (PL) spectrum of modified Si nanoparticles was changed since the protective agent had modified the surface states, thus altering the light emission characteristics.

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