The suitable conditions of ultrasonic/ultraviolet（US/UV） nano-Fe~0 Fenton-like process for the treatment of high-concentration complex heavy metal wastewater were studied,and the removal mechanism of chemical oxygen demand （COD） and complex heavy metals by this process was ex‐plored.The experimental results show that under the action of US/UV,nano-Fe~0 Fenton-like process can treat the complex heavy metal wastewater with COD concentration of 1738.86 mg/L,total chromi‐um of 473.14 mg/L,total nickel of 43.35 mg/L and total copper of 8.53 mg/L.When the pH value is 3,the temperature is 65℃ and the oscillation speed is 150 r/min,the optimum condition of nano-Fe~0 is 9.6 mg/L.After reaction for 20 min with 1 mL/L of H 2 O 2 ,the removal rates of COD,total chromium,total nickel and total copper were 96.75%,99.99%,99.94% and 99.57% respectively.Compared with the traditional Fenton method,the reaction rate was speeded up,the reaction time was shortened by 66.6%,the removal efficiency was improved by 10%,and the sludge amount was reduced by 13%.Af‐ter repeated use of nano-Fe~0 for three times,the removal rate of complex heavy metals is still above 50%,which shows that nano-Fe~0 has good reusability.Therefore,nano-Fe~0 has a good application pros‐pect in the treatment of high-concentration complex heavy metal wastewater

烧结钕铁硼永磁材料自诞生以来,极大地提升了应用设备的性能,同时也拓展了许多新的应用领域.而近年来,新能源汽车、工业自动化、风力发电和人工智能机器人等领域的蓬勃兴起,对该磁体的矫顽力、热稳定性和耐蚀性等性能又提出了更高的要求.为此,生产研究人员多采用工艺优化、表面涂覆和合金化的方法,改善其实际应用性能.重稀土镝或铽的添加,表面镀锌、镍是较为常用的,而近年来也出现了采用合金与化合物扩散改性的研究,也可以达到比较好的效果.本文综述了这种方式改性的研究进展,概述了常用的化合物种类和这些化合物对于磁性能、耐蚀性能和热稳定性的提升情况,并对采用合金与化合物扩散改性烧结Nd-Fe-B合金的研究进行了展望.

烧结Nd-Fe-B磁体的磁性能及微观组织结构与其制备工艺尤其是烧结回火工艺密切相关.为此,制备了超高矫顽力的Nd-Fe-B烧结磁体,分析了回火工艺对其微观结构及磁性能的影响.结果表明,烧结Nd-Fe-B磁体的主相晶粒尺寸及形状主要由烧结工艺决定,高低温两级回火工艺会改善磁体晶界富Nd相分布,使其更均匀和连续分布在主相晶粒周围,有助于提高磁体的矫顽力.对于IVU16真空波荡器用高矫顽力烧结Nd-Fe-B磁体,经高低温两级回火后磁体Hcj提高了9.3％.

在Y3Al5 O12前躯体纳米粉末的制备过程中,容易引起团聚,或者带入杂质而降低其纯度,且其粒度均匀性也可能受到影响,这些缺陷是大多数合成方法都在一定程度上存在的.而YAG透明陶瓷和掺杂YAG发光材料等必须要用高纯、超细并且团聚少的粉体.为此,探索采用一种基于sol-gel法的快燃技术来制备Y3Al5O12前躯体纳米粉末,并将其与传统sol-gel法得到的结果对比.研究表明,两种方法获得的YAG物相纯度基本一致.但是,快燃技术制备的YAG粉末形状单一,颗粒之间的连接较为松散,以软团聚为主,且颗粒粒径偏差小,其平均粒度为63 nm;而传统sol-gel法合成的YAG粉末形状不规则,种类多,颗粒之间连接较为紧密,较多的呈现硬团聚特征,且颗粒粒径也有较大的偏差,其平均粒度约为85 nm.因此,可以将快燃技术用于合成YAG及其他类似的陶瓷前躯体粉末.

采用硫酸复盐沉淀法、草酸二次沉淀法和磷酸盐沉淀法从烧结Nd-Fe-B废料中回收Nd2O3,先以硫酸或草酸对工业生产的Nd-Fe-B废料进行预处理,钕离子经碱化、酸溶解后,再分别采用草酸或碳酸铵沉淀而与铁分离,最后经煅烧得到Nd2O3粗产品.借助扫描电镜观察Nd2O3粉末形貌,并通过EDTA滴定确定Nd2O3产品的纯度并计算回收率.结果 表明,不同方法制取的Nd2O3粗产品纯度和回收率相差较大,Nd2O3纯度为74％～92％,总回收率为24％～29％,粒径为3～200 μm,形状不规则,分散性较高,且颗粒表面和内部有很多细孔,多为蓬松状.综合考虑工艺流程的复杂程度以及Nd2O3纯度和回收率,硫酸复盐沉淀法在烧结Nd-Fe-B废料回收Nd2O3的实际应用中较有优势.

YAG(Y3 Al5 O12)具有优异的物理化学性能,被广泛用作激光和其它发光基质材料.制备透明的YAG陶瓷对粉体有着极高的要求,为了能够制备出性能极其优异的YAG陶瓷粉体,人们开发出了许多方法.本文综述了近年来YAG粉体制备的研究,介绍了常用制备YAG粉体材料的方法,对各种制备方法的优缺点进行了总结.

采用一种基于溶胶-凝胶法的快燃技术来合成钇铝石榴石(YAG,Y3Al5O12)前驱体纳米粉体,并将其与传统溶胶-凝胶法所制样品进行比较.结果表明:两种方法获得的YAG物相纯度基本一致.但是,快燃技术合成的YAG粉末形状单一,颗粒之间的连接较为松散,以软团聚为主,且颗粒粒径偏差小,其平均粒度为63nm;而传统溶胶-凝胶法合成的YAG粉末形状非常不规则,种类繁多,颗粒之间的连接较为紧密,较多的呈现硬团聚的特征,且颗粒粒径也有较大的偏差,其平均粒度约为85nm.

Iron foil is the important target material for the experimental research of state equation .Its micro structure has great influence on the quality of target and the results of physics experiment .The cold rolled iron foil was selected as raw material which was used in the preparation of target .It was hot-pressed at different temperatures in vacuum for 60 min first .And then ,microcrystalline size ,strain ,grain size ,preferential orienta-tion and residual stress of these samples were measured and characterized .Based on it , the trends of the above parameters were analyzed .Furthermore the evolution process of micro structure was discussed .The results indicate that the samples undergo recovery , recrystallization and grain growth sequentially with the increase of temperature .The recovery is the predominant mechanism at the temperature below 550 ℃ .In this stage , microcrystalline grow s up ,the residual stress decreases ,and the shape and preferential orientation keep stable . When the temperature exceeds 550 ℃ , the recrystallization completes and the samples enter into the stage of grain growth .The micrometer-sized equiaxed grains replace the fibrous tissue in the original sample ,and its preferential ori-entation obviously transforms .The abnormal grain growth phenomenon does not appear in all samples .

采用失重法研究了非均一形状的烧结NdFeB磁体样品在不同温度、不同浓度的蒸馏水、河水、硫酸、氢氧化钾溶液、氯化钾溶液中的腐蚀情况,并根据样品具体形状估算出表面积,从而得到不同条件下样品的平均腐蚀速率.结果表明,样品在酸介质中的腐蚀速率较快,且腐蚀速率随酸溶液浓度升高而增大;而低温、高浓度的碱和盐溶液对样品的腐蚀性较弱;蒸馏水对样品的腐蚀性大于自来水.

The magnetic properties of sintered Nd-Fe-B alloy are excellent which enlarges its application scope. However,it has several defects,imcluding low toughness,high brittleness,poor shakeproof and shock resistance, which restrict its application in the high accuracy instrument and high velocity electrical machine.Therefore,resear-ches on its fracture mechanisms and toughening techniques is important.The latest research achievements on fracture mechanism of Nd-Fe-B alloy are summarized.The primary fracture mechanism in the alloy is the intergranular frac-ture,but defects can increase the probability of transgranular fracture.On the other hand,toughness of the alloy might be enhanced by element addition and process improvement.However,these methods did not improve the me-chanical properties fundamentally.As a result,further researches should be conducted in order to find more effective toughening methods.

在制备烧结Nd-Fe-B的过程中加入少量废弃Nd-Fe-B磁体,并相应减少Nd、Fe、B原料的投料量,再经过成形、烧结和后加工工序制成样品;对含废料与不含废料的Nd-Fe-B样品的粉末粒度、微观结构和磁性能进行了测试和比较分析.结果显示,含废料样品的粒度集中性略低于不含废料样品,且有少部分颗粒粒径超过100 μm,而二者的微观结构基本一致,且随着老化温度升高,磁通量均有所减小,热变化规律相同.

Research status and development trend of Al/Fe connecting technology were introduced in China and other country.The advantage and limitation were analyzed.The influences of temperature,holding time,the pressure of diffusion bonding on microstructure of Al/Fe joint were mainly expounded.Finally,research direction of Al/Fe vacuum diffusion bonding was forecasted.

烧结Nd-Fe-B合金加工过程中会产生10%~30%的边角料、成型中可能的氧化粉末、烧结过程失误的废品及使用后的产品等,其中含有大量的Fe与丰富的稀土元素。一般研究主要的注意力集中在稀土元素的回收,也有部分仅针对Fe元素的回收利用研究,而对其他元素丢弃或者采用另外的方式处理,造成材料、资源的浪费,工艺成本亦相应增加。为综合利用有限资源,在（Pr Nd）xB1.05Al0.5Nb0.3Fe98.15-x合金的制备过程中,采用物理手段添加一定含量的废弃Nd-Fe-B磁体,从而制备出合格产品,并与不添加废弃磁体的（Pr Nd）xB1.05Al0.5Nb0.3Fe98.15-x合金进行对比研究。结果表明,经X射线衍射（XRD）分析,在废料少量添加的情况下,二者的物相相似,且经50℃老化处理1 h后,两种样品磁通量分别降低了0.51和0.52 Wb,经70℃处理1 h后,降低了0.96和0.95 Wb,再经90℃处理1 h后,又分别降低了0.80和0.82 Wb。相对于无废弃Nd-Fe-B磁体的样品,添加废料样品粉末颗粒较粗,比表面积较小,离散性稍大,但是其块体样品的微观结构基本一致。

以Y(NO3)3·6H2O、Al(NO3)3·9H2O、硝酸铵和柠檬酸为原料,采用凝胶燃烧法合成YAG粉体.采用XRD、SEM、激光粒度仪测试手段对YAG粉体进行表征.通过正交实验对凝胶燃烧法合成YAG粉体的主要工艺参数进行了优化,得出在现有条件下的最佳工艺参数为T=270℃,pH=2,CA/M=7/6,N/CA=2/4.

The proper connection ways for some materials,which need to be bonded each other,should be selected according to their size,shape,type and structure,and it is special to the small fine thin films. So in this paper,the ways,such as the physical vapor deposition technology,the precise rolling technology,the brass solder technology,the friction welding technology and the diffusion welding technology,etc. were summarized,especial-ly their applicability,merits and demerits,pointing out that the diffusion welding technology is more adaptable to the small fine thin films,whose development prospect was also expected.

钇铝石榴石(YAG)具有优异的机械和光学性能,在包括激光基质材料等领域内均有较好的用途.但是制备这种质量良好的多晶陶材料,首先必须要有高纯度、超细而均匀的前躯体粉末.在制备此粉末的过程中,需要面对和解决诸多问题,比如原材料、制备方法的选取和相应工艺的优化以及创新、所获得粉末的团聚以及解团聚等.本研究分析了近年来YAG前躯体粉末制备中的若干问题,相应提出了可能的解决办法和途径.

以硝酸铝(Al(NO3)3·9H2O)和硝酸钇(Y(NO3)3·6H2O)为原料,碳酸氢铵(NH4HCO3)为沉淀剂,PEG 1000为分散剂,采用改进共沉淀合成了钇铝石榴石(YAG)前驱体粉末.用热重分析仪、粒度测试仪、X射线衍射仪等分析了粉末的结构和性能.结果表明,改进共沉淀能制备纯度较高的YAG相;陈化时间对YAG粉体材料的结构和性能有一定的影响,当陈化时间为12h时,制得的YAG粉体纯度较高,粒径分布较为均匀,其比表面积达到了367.79 m2/kg,中位径为7.52 μm.

In order to establish a succession law of every phase in sintered Nd–Fe–B magnets marked as 38/38H/38SH/38UH, four alloys of Nd33−x Dy x Al0.7Nb0.6Cu0.1B1.05Febal. (at%) were investigated after smelting processing, sintering processing, high-temperature tempering processing, and high- and low-temperature tempering processing. It is found that the four phases: the Nd2Fe14B matrix phase, Nd-rich phase, B-rich phase, and defect phase can be inherited by means of the subsequent processing. These phases might have the special constitution and appearance in the different states. Magnetic properties also have succession law. In every processing except smelting one, the values of remanence and maximum energy product hardly alter, but the value of coercive force increases gradually.

分别以柠檬酸、乙二醇、甘氨酸为燃烧剂,采用溶胶-凝胶燃烧法合成YAG粉末,并用热重/差热仪、X射线衍射仪、红外吸收光谱仪等对其进行表征.结果表明:在溶胶-凝胶燃烧法制备YAG粉末的过程中,柠檬酸为最适宜的燃烧剂,以乙二醇和甘氨酸作燃烧剂时所需结晶温度偏高,且以甘氨酸作燃烧剂制备的YAG粉末中存在YAM和YAP等中间相.以柠檬酸为燃烧剂时,YAG前驱体完全转变为纯YAG相的临界温度约为900℃,将其在900℃以上温度下煅烧2h后,即可得到纯度较高的YAG粉末.

研究了采用高压加速老化试验机对HD工艺和普通工艺制备的两种(PrNd)xAl0.12Nb0.2Cu013B1.05-Fe98.5-x合金样品在温度为130℃,压强为0.22 MPa,湿度为95％的极端环境条件下处理168 h后的失重情况,通过磁化特性自动测量仪检测了其老化前后的磁性能,用激光粒度仪测试了其原始粉末粒度,并用Matlab软件对两种样品的SEM微观结构照片中富Nd相的含量进行了分析.结果表明,两种样品的富Nd相含量有区别,普通工艺制备样品为7.63％,而HD工艺制备样品为7.80％,且磁性能也较好,粉末平均粒度较小,前者却相对较大.此外,二者的平均失重率分别是-3.5386 mg·cm-2和-0.1645 mg·cm-2.另一方面,经过失重试验后,前者的剩余磁通密度Br降低了0.74％,后者仅仅降低了0.64％,两者的内禀矫顽力Hej也分别降低了2.28％和1.14％,方形度Hk/Hb分别降低了24.9％和0.10％,最大磁能积(BH)max降低了2.84％和2.06％.