常用的奈米金屬粉體中，鐵粉是主要的項次之一，多用於高性能磁記錄材料、磁流體，吸 波材料、導電槳料、奈米導向劑與地下水污染物處理，奈米鐵粉具有易燃的特性，在鐵粉原料 製造過程使用超微粒研磨時，會產生部分奈米尺度粉體，當然也就具有燃燒的危險性，本文以 超微粒鐵粉實場研磨為例，以高速攝影機拍攝研磨操作發生之熱危害過程，能將結果視覺化， 以提供業者直接、簡單但具體的金屬粉塵熱危害發展程，以為熱危害防治之用。於實場操作中 先建立濕度、溫度、靜電與液態氮的操作特性，以便固定操作條件，並據以選定實驗所需之熱 危害操作條件，及熱危害在實體系統發生的位置作為實驗時感知器安裝位置之用，操作結果顯 示，未接地的研磨系統其靜電累積發生於絕緣之塑膠管，且風速高者靜電累積量比較大，再經 由調控液態氮流量、成品排風速度與進料性質等操作參數，觀察產生熱危害過程特性，成功定 位出危害點為4英吋排風塑膠管與旋風分離器入口交接處。
實驗發現，純粹以鐵粉進行超微粒研磨並未產生燃燒現象，但加入2% 35nm之奈米鈦粉 體，並將產品排風量增加到16m3/mm時即出現燃燒現象，研判應為奈米鈦金屬粉體增加了混合 粉體之可燃性，並在傳輸過程中因方向改變造成之摩擦、衝撞提供足夠能量所致；以高速攝影 機聚焦危害點，測得燃燒瞬間之火焰發展過程與溫度分布曲線；實驗結果亦發現採用液態氮冷 卻與鈍化措施，能維持鐵粉超微粒研磨之安全操作，由於全程為實廠操作，測試過程與結果對 業界將有實質幫助。

Nano-scale iron metal powder is commonly used in nano-industry. Such as magnetic recording materials, magnetic fluid absorbing materials, conductive paste, nano-directing agent and groundwater pollutant treatment . The flammable property of nano iron powder has been confirmed. Ultrafine grinding process will produce some nano-scale powder. In this paper, a practical ultrafine iron grinding process is toke as an example in this paper; to explore the thermal hazard developing process during grinding operation with visualizes treatment by using high speed camera. Provide direct, simple but specific metal dust thermal hazard development process in the ultrafine grinding operation, that the thermal scenario prevention purposes. First create the operating characteristics of humidity, temperature, static electricity and liquid nitrogen in practical operating field. For fixed operating conditions, so the conditions of manufacturing thermal hazards and thermal hazards occurred position is selected. Operating results of the grinding system is not grounded its static build-up occurred in the nonconductive plastic pipe, and blowing speed greater than the higher accumulation of static electricity. Further, the liquid nitrogen flow, the exhaust speed and feed products the nature of hazards observed during thermal hazard development. Successfully locate a hazard point of exhaust cyclone inlet junction of the 4" plastic pipe. Here we focus on high-speed camera measured the development of the combustion process and the moment of flame temperature distribution curve, also found that the use of liquid nitrogen cooling and passivation of iron ultrafine particles to maintain the safe operation of grinding. Combustion phenomenon appears when adding 2% 35nm in the nano-titanium powder, and the amount of exhaust products to 16m /min. That should be judged due to friction caused by collision raised In the changing direction of the transmission process. Because the procedure is the real plant operation, the testing process and results will be of material assistance to the industry.