【作者】 高帆；

【导师】 张连宝；

【作者基本信息】 北京工业大学 ， 材料学， 2004， 硕士

【摘要】 粉末冶金是冶金学的一个重要分支，而烧结工艺则是影响粉末产品质量的一个关键环节。进入二十一世纪，随着各项新技术的诞生及应用，现代工业得到了飞速发展，粉末冶金制品所占工业产品的比重也日益增大。这就对粉末冶金产品的质量和性能提出了更高的要求，本课题所探讨的空心阴极等离子快速高温烧结工艺就是利用空心阴极放电效应作为新的烧结手段，实现对难熔金属及陶瓷的高温、快速烧结。同时引入渗金属工艺，丰富铁基粉末的烧结方法。本课题从空心阴极的放电特性实验出发，探讨了空心阴极的点燃条件、放电电流和升温特性以及气压、电压对电流密度和温度的影响。结果表明：空心阴极点燃的基本条件是负辉区的交叠，通过负辉区内电子的振荡实现电流的放大，与普通平板阴极放电相比较，在放电电压 V、气压 P 等条件相同的前提下，圆筒形空心阴极能够拥有更大的输出电流。圆筒形空心阴极效应能够在短时间内实现温度的快速升高，可以根据该特点将其利用在快速升温的工程领域。通过对加入不同助剂的 AlN 陶瓷试样的烧结实验，探讨了制备高性能 AlN陶瓷材料的工艺参数，以及烧结工艺对微观结构及 AlN 陶瓷热导率的影响。结果表明：通过调节放电电压、气压等条件，可以充分控制空心阴极的输出功率，利用其大能量，高密度的等离子体，完成陶瓷材料的快速烧结；在 1700℃，保温 3小时的烧结条件下，添加 5.5wt% Y2O3－CaO－Li2O 的 AlN 烧结体具有最高 98.88％的相对密度，热导率可达到 93.8W/mK。在对铁基粉末的烧结实验中，同时进行离子渗金属复合处理。显微组织分析可以显示在不同的工艺参数条件下，烧结体的致密化过程。结果表明：通过对空心阴极工艺参数进行调整，可以在获得致密化铁基粉末烧结体的基础上于表面形成完整的合金化渗层。更多还原

【Abstract】 Powder Metallurgy is a very important branch of metallurgy. And the sinteringprocess always plays a key role which can affect the quality of the powder metallurgyproduct. Since we’ve step into the new century, the modern industry have got a bigdevelopment with the naissance of new technology. And the powder products countmore among the industry products. It puts forward the higher request about theproperty and the quality of the powder product. In this paper, it is discussed that theHollow Cathode Discharge can be used as a method in speedy and high temperaturesintering process which can be applied in high melting point metal and ceramicmaterial. And the saturating metal technics can be also added in the process. It willenrich the technique of iron powder sintering. In this paper, it is started from the discharging discipline of the Hollow CathodeDischarge. The lit condition, discharging current, and the rising temperature propertyare also discussed. It is followed that the pressure and the voltage influence thecurrent density and the temperature. The result shows that the basic lit condition is theoverlap of negative glow. The current can be amplified through the oscillation ofelecttrons. With the comparison of cylinder-shaped HCD and parallel plank HCD, thelatter can provide more powerful current under the same condition of voltage andpressure. And it can accelerate the rising of temperature which can be applied in thehigh temperature engineering area. With the sintering experiment of different additives AlN ceramic, it is discussedin this paper that the appropriate parameters can be very helpful in makinghigh-powered AlN ceramic. The result shows that with the adjustment of the sinteringparameters such as voltage and pressure, the output power can be well controlled. Andthe fast sintering can be achieved with the high density plasma. In short time, thesample can get compactness. According to the experiment, the relative density of theAlN sample can be 98.88％ and thermal conductive rate of the AlN sample canreach 93.8W/mK under the conditions of 5.5wt% Y2O3－CaO－Li2O addictive;1700℃;and 3 hours’holding time. In the experiment of sintering iron powder, alloying metal process is added. Themicrostructure can clearly indicate the steps of the samples’ densification process II<WP=6>摘 要during different parameters.The result shows that with the adjustment of the HCDparameters, iron powder can be sintered closely. And the integrate alloying layer canbe formed on the surface as well.更多还原