粉末的

The critical heating rate for different body radius was predicted by comparing the gas pressure when the peak degradation rate occurred with the threshold body strength which was determined by the diametric compression test of the green body during thermal debindering.

摘 要：以聚乙烯醇和NiFe2O4/Ni型金属陶瓷压坯为对象，采用热重分析研究PVA在N2气氛中的热脱脂行为，建立PVA热脱脂速率的数学模型，在此基础上，模拟并计算PVA分解产物气体在多孔粉末压坯内的压力构建情况；结合粉末压坯脱脂强度测试结果，分析粉末压坯在脱脂过程中压坯尺寸、粘结剂含量等因素对升温速率和脱脂时间的影响，获得不同半径尺寸压坯的极限升温速率。

Paper in magnetic patterns, pulp to join jiseizai powder, when paper pulp and magnetic powder is closed at magnetic Board shapes implantation magnetic anti-false paper, magnetic powder be 200 screen, and it should also be stain.

在成纸中有明显的磁性图案，纸浆中加入磁性材料粉末，当纸浆和磁性粉末就按磁板图案的形状植入磁性防伪纸中，磁性粉末，应经过200目筛，并还应染色。

There is much metal powder in liquid and the visitors can use magnets to attract them to the top of the container and then let go. When the powder slowly falls down in the liquid, it produce beautiful and diverse patterns like the one produced by ink drops in water.

在液体中有许多的金属粉末，观众可以手持吸铁石隔着容器把沉在底部的金属粉末吸引到上面来，然后一松手金属粉末就会缓缓落下，形成如墨滴溶解般美丽而又富有变化的图案。

The stability of sliding contact of metal impregnation carbonmaterial is worse than that of copper-base powder metallurgy material.

4浸金属碳材料的减摩性不如铜基粉末冶金材料的，其摩擦系数比铜基粉末冶金材料的摩擦系数大，其值分别大了14.4％—150％；同时，浸金属碳材料的摩擦稳定性也不如铜基粉末冶金材料的。

Moreover, the hot compressive deformation behavior of the RS/PM AZ91 magnesium alloy and AZ91 alloy matrix composite were also investigated, the conclusions are drawn as follows:1. The processing parameters of the atomization-twin rolls quenching technology were optimized as follows: the diameter of the nozzle 1mm, the wheel velocity 25m/s, the pressure of atomization gas 0.3MPa and Ar gas for melt injection 0.1MPa. The RS AZ91 alloy flakes exhibited fine and uniform microstructures. When the flakes were extruded at 673K, extruded velocity of 0.1mm/min and extrusion ratio of 25:1,the magnesium alloy rods with clean surface, uniform dimension and excellent mechanical properties were obtained.2. The RS AZ91 magnesium alloy powders prepared by atomization-twin rolls quenched technology exhibited fine equiaxed grains with the grain size of 1-3μm, the phase constituent included supersaturate solid solution phaseα-Mg and miner fineβ-Mg_(17)Al_(12) phase. The as-extruded materials also exhibited equiaxed grains with the size of 5-7μm and a large number of fineβ-Al_(12)Mg_(17) and fewer AlMg_2Zn phases were detected in the alloy.

本文还研究了快速凝固/粉末冶金AZ91镁合金热压缩变形流变应力行为，快速凝固/粉末冶金法原位生成Mg_2Si增强AZ91镁基复合材料，经过系统的研究，获得如下结论：1、雾化-双辊急冷法在下列工艺参数组合下：双辊线速度25m/s；喷嘴直径1mm；熔体压射压力0.1MPa；雾化气体压力0.3MPa。，可获得宏观尺寸细小、微观组织均匀细小、综合性能优良的的快速凝固AZ91镁合金细碎箔带，快速凝固箔带在挤压温度为673K、挤压速度为0.1mm/min，挤压比为25：1时，可获得的外表光洁、尺寸均匀、组织性能优异的镁合金棒材。2、雾化-双辊急冷法制备的AZ91镁合金粉末态为细小等轴晶组织，晶粒尺寸1-3μm，组织为α-Mg过饱和固溶体和微量的细小β-Mg_(17)Al_(12)相组成；粉末挤压棒材为等轴晶组织，晶粒尺寸5-7μm，组织中含有大量细小的β-Al_(12)Mg_(17)以及AlMg_2Zn析出相，室温力学性能，抗拉强度383MPa，屈服强度275MPa，断后伸长率7.5%。

Regardless to the research development or industrial application, nano metal powders are extensively discussed. Within these powders, the flammable and explosible nano aluminum, titanium and iron powders produce a great amount production and apply widely. Meanwhile, the surface/volume ratio of powders is increased significantly under nano scale, in which to enhance the ignition opportunity. Thus, the dust explosion hazard risk of nano powders could remarkable rise. In addition, the comparison of explosion phenomenon, test methods and quantification parameters between nano and micro scale is necessary to deeply investigate further. So that this project operates the explosion characteristic experiments to measure and determine such the maximum explosion pressure, minimum explosion concentration and explosion characteristic Kst value on above mentioned three nano metal powders. Expectantly, to provide the appropriate recommendations of safety prevention for nano dust explosion based on the experimental results.

奈米金属粉末无论是研究发展或是工业界应用，目前皆是广泛讨论研究之材料，其中，奈米铝粉、奈米钛粉以及奈米铁粉等可燃、爆性粉末，均有高额产量及大量应用领域，与此同时，在粉末粒径进入奈米尺度的情况下，粉尘比表面积大幅提升，增加此三种粉尘可被点燃的机会，因此，潜在的粉尘爆炸危害风险将广幅增加，另外，微米尺度粉尘爆炸的现象、测试方法以及量化参数是否具有相同的实验尺度基点，也需要深入探讨，故本次计画针对上述三种奈米金属粉末，进行三种不同粒径的爆炸特性参数实验，如最大爆炸压力、最低爆炸浓度以及爆炸特性参数Kst值之量测与计算，期能量化其粉尘爆炸特性，并据此提出适当的安全防护建议。

Project Content and Scale: To adopt a mixed production transmission device of micro glass powder such as axle bush, the anti-abuse movement capacity of gears can be raised 2-3 times, especially in the condition of high-temperature without lubricant .About 70% of the world automobile gear is made in the way of metal powder metallurgy. However, utilizing method of pure metal powder metallurgy may cause a fatal weakness, that is, because sinter oxide membrane will arise among crystal, this may lower its intensity.

项目内容和规模：采用微玻粉末混合生产的传动装置如轴瓦，齿轮其抗磨蚀能力提高2—3倍，特别在高温无润滑条件下优势更为明显，全世界70%的汽车齿轮是用金属粉末冶金为法制造的，但纯金属粉末冶金件有一个致命弱点，因颗粒间会产生烧结结氧化膜而降低强度。

It is discovered that the strength of flexible metal cloth decreased with the increasing of the powders'size (45-180μm). The tensile strength of the cloth decrease from 72PSI to 3. 8PSI with the powder size increasing from 45μm to (125180)μm.

研究了金属粉末颗粒形貌、尺寸和连接物含量对金属粉末柔性布连接强度的影响，发现随着金属粉末颗粒尺寸的变大(45—180μm)，柔性布的强度会降低。

The results show that: the tensile strength, flexural strength and flexural modulus increase by about 10.4%, 62.1% and 122.3% respectively when the mass fraction of the aluminum powder increases from 0 to 50%, while elongation at break and impact strength decrease by about 65.0 and 74.4% respectively; the tensile strength, elongation at break and impact strength all increase with decreasing the particle sizes of the aluminum powders.b Nylon-12 coated metal powders for the indirect SLS process were prepared by the dissolution precipitation process. The coated powders have only 1.0 wt% nylon-12, and their SLS green parts have sufficient strength for features as small as 1.0 mm to be built and post-processed and high dimensional accuracy. The green parts were subjected to the post processing processes including binder decomposition and infiltration of epoxy resin, and then the metal/polymer composite parts with relatively high strength and accuracy were formed.At present, micron-scale inorganic fillers have been widely used to reinforce nylon SLS parts.

将该法制备的尼龙12覆膜金属粉末用于以下两个方面：a使用铝粉增强尼龙12的SLS成形件，通过溶剂沉淀法制备尼龙12覆膜铝复合粉末，研究了铝粉含量及粒径对SLS成形件性能的影响，结果表明：铝粉分散均匀，并与基体有良好的界面粘接；当铝粉含量从0增加到50wt％时，成形件的拉伸强度、弯曲强度、弯曲模量分别提高10.4％、62.1％和122.3％，冲击强度和断裂伸长率下降65.0％和74.4％，耐热性及尺寸精度也得到提高；断裂伸长率、冲击强度及拉伸强度均随着铝粉粒径的减小而增大。b使用溶剂沉淀法制备了间接法SLS用尼龙12覆膜金属粉末，该覆膜粉末中聚合物粘接剂的含量仅为1.0 wt％，其SLS初始形坯具有较高的精度以及足够满足后处理要求的强度，最小精细结构的尺寸达1.0 mm。

Results showed that at a given position on the storage vessel surface, the hoop strain was increased with a higher packing fraction of alloy powders during the cyclic hydriding/dehydriding reactions. This resulted from a larger amount of pulverized fine powders generated by a larger packing fraction of alloy powders.

结果显示，在储氢罐表面之特定位置上，其切线方向应变随著粉末填充率提高而增加，这是由於较高的粉末填充率产生较多的粉碎细小粉末所导致。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。