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Ⅰ.绪言金属钨具有极高的熔点(3660°K),是最好的高温材料。在其多种用途中,最大的问题是缺乏韧性,在加工中由于其塑性-脆性转变温度较高,常因塑性不佳而报损。不少研究报告指出,使颗粒超细化能大大提高材料的强度和韧性,降低金属的塑性-脆性转变温度,从而改善金属的性能。金属钨粉的重要用途之一是用作制取硬取合金原料碳化钨。近年来出现的超细晶粒硬质合金,具有硬度、强变二者兼优的性能,是切削加工诸如钛合金、耐热钢、镍基和钻基合金等难加工新型材料的良好刀具。研制超细晶粒硬质合金,提高硬质合金质量,是我国急待解决的重大赶超课题。制造超细晶粒硬质合金的前提是要求制备出超细钨粉。目前国内外采用多种制备超细钨粉的方法,其中最引人注目的是六氯化钨氢还原法。六氯化钨氢还原法生产的钨粉,具有粒度超细、颗粒形状规整、粒度分布狭窄、化学纯度高及晶粒不易长大等特点,是其他工艺所不能比拟的。超细钨粉的研制成功,不仅为高质量超细晶粒硬质合金提供了好原料,还会在人造金刚石钻头,高比重合金、钨材、电触头,过滤器等方面,找到重要用途。
Ⅰ. Introduction Tungsten metal has the highest melting point (3660 ° K) and is the best high temperature material. Among its many uses, the biggest problem is the lack of toughness, due to its plasticity during processing - brittle transition temperature is higher, often due to poor plastic reported damage. Many studies have pointed out that the ultra-fine particles can greatly improve the strength and toughness of the material, reduce the metal plastic - brittle transition temperature, thereby improving the performance of the metal. One of the important uses of metal tungsten powder is to make tungsten carbide as a hard-alloyed material. In recent years, the emergence of ultrafine grained cemented carbide, with hardness, strength and stability of both the performance of the cutting is such as titanium alloy, heat-resistant steel, nickel-based and drill-based alloys and other difficult to process new materials, a good tool. The development of ultra-fine grain cemented carbide to improve the quality of cemented carbide is a major catch-up project to be solved in our country. The premise of manufacturing ultrafine grained cemented carbide is to require the preparation of ultrafine tungsten powder. Currently using a variety of methods to prepare ultrafine tungsten powder, the most notable is the tungsten hexachloride hydrogen reduction method. Tungsten hexachloride hydrogen reduction of tungsten powder produced with ultrafine particle size, particle shape regular, narrow particle size distribution, high chemical purity and grain growth is not easy, and other characteristics can not be compared. The successful development of ultra-fine tungsten powder not only provides good raw materials for high-quality ultrafine-grained cemented carbide, but also finds important uses in synthetic diamond bits, high-proportion alloys, tungsten materials, electrical contacts and filters .