微量SiO2对钍钨合金烧结性能的影响

介绍了钍钨产品生产工艺的历史和现状,说明了中频烧结钍钨合金的现实意义。试验采用在钍钨粉末中添加微量石英粉的方式,降低烧结温度,提高烧结密度,实现了中频烧结,并且满足了后续加工工艺的要求。     

大尺寸三元复合稀土钨坯条烧结工艺研究

对大尺寸（Φ20 mm）三元复合稀土钨坯条的烧结工艺进行了研究。通过在低温阶段（≦1 800 ℃）增加烧结时间、高温阶段（≧2 000 ℃）增加烧结时间、高温阶段增加保温平台的方法进行烧结。结果表明：对于在1 800 ℃以下，烧结时间短容易形成大孔洞及出现“烧生现象”造成密度低，而在高温烧结阶段延长烧结时间稀土元素扩散挥发现象严重，造成坯条内稀土元素分布不均匀，通过在低温阶段增加烧结时间，高温阶段增加保温平台缩短保温时间的方式可以抑制稀土元素的扩散和挥发密度达到18.2 g/cm3。     

环保型稀土钨电极坯条制备技术研究

本文针对环保型稀土钨电极坯条高效低能耗制备技术进行研究,对钢模压制和等静压压制进行了对比试验,并对垂熔烧结和中频烧结进行了对比试验。结果表明：等静压压制坯条——中频烧结方式制备的坯条密度、组织更均匀,减少原材料消耗2.3%,并在后续加工过程中有效避免内部裂纹的产生。此法生产可实现批量操作,比单根操作效率明显提高,电能消耗降低70%以上,为环保型产品的规模推广应用提供了技术支撑。     

环保型稀土钨电极坯条制备

对钢模压制和等静压压制稀土钨电极坯条进行对比试验,并比较垂熔烧结和中频烧结的效果。结果表明,等静压压制—中频烧结方式制备的坯条密度、组织更均匀,减少原材料消耗2.3%,电能消耗降低70%以上,加工性能及产品合格率较传统工艺更高。制得的稀土钨电极,30 A以上引弧成功率100%,所得焊缝平整,焊接效果优良。     

多元稀土钨线材轧制致密化及退火分析

通过使用二辊轧机,采用一火八道次的热轧制工艺进行多元稀土钨合金线材开坯,对开坯后的多元钨合金线材进行退火处理。利用扫描电子显微镜(SEM)、能谱、光学显微镜、显微硬度计等表征分析轧制致密化过程,轧制、退火对钨线材组织性能的影响。研究结果表明:轧制过程中烧结孔发生变形、闭合,最终在剪切力的作用下消失,多元稀土钨线材密度增加,在轧制温度1 650℃,保温时间30min,轧制速度170m/s下进行轧制,孔隙度由6.50%减少至4.61%,钨线材密度由17.84g/cm3增加到18.12g/cm3;轧制组织中的晶粒在轧制方向上伸长,形成相互挤压、重叠的加工态组织,热轧过程主要发生动态回复过程,在晶粒内部形成胞状亚结构;在1 100℃至1 300℃退火保温时仅发生回复并未再结晶,在1 400℃保温60min发生再结晶,晶粒未完全长大,在1 600℃退火保温60min时,再结晶过程完成。     

烧结温度对3D打印B30铜镍合金制品力学性能影响的研究

为了避免传统熔炼法制备合金易产生枝晶偏析的问题,以球型的铜粉和镍粉为实验材料,经过机械混合的合金粉末与聚乙烯醇(PVA)溶液按照质量比为526的比例混合制得合金金属粉末浆料。通过3D打印制备了B30铜镍合金的样件坯体,并通过脱脂和烧结得到合金样件。研究了在不同的烧结温度下制件的密度、拉伸强度和收缩率的变化规律。结果表明,样件的表面随着烧结温度的升高逐渐趋近于镍的颜色,样件的密度、拉伸强度和收缩率都出现了随着烧结温度的升高先快速上升后缓慢上升的现象,并在烧结温度为900℃时样件的收缩率、密度和拉伸强度都出现了增速减慢的现象。样件在烧结温度为1 150℃时的收缩率达到最大值3.45%,密度达到最大值5.05g/cm3,拉伸强度达到40.26MPa。     

不同压制条件下铜基粉末的致密化研究

研究铜基粉末在不同压制条件下压坯密度与相对密度的变化.结果表明,添加少量石墨有利于提高压坯的相对密度,当石墨含量超过1%时,以片状形貌存在的石墨大大增加了与铜基体的孔隙,相对密度急剧下降.相同压力下,温压压制的压坯密度明显高于冷压压制,在压制压力为500～600MPa时,密度提升达0.24g/cm3.对所研究的铜基粉末,最佳烧结温度和压制温度分别为920℃和130℃.     

钛粉烧结工艺参数控制研究

为得到适宜的钛粉烧结工艺参数,从而制备出全致密高性能的钛粉末冶金件,研究了烧结温度、保温时间和升温速率对烧结坯收缩率和相对密度的影响。结果表明:烧结试样的收缩率及相对密度随烧结温度、保温时间升高而增大,随升温速率减小而增大。提高烧结温度可以降低烧结坯孔隙率、减少残余孔隙尺寸,但可能导致材料力学性能下降; 保温时间达到4 h后,孔隙逐步扩散、长大和湮灭,大孔隙消失; 较低升温速率有利于组织内部缺陷消失、内应力释放和气孔消除。综合考虑烧结效率、烧结炉温度极限、烧结组织控制、烧结试样收缩率、烧结试样相对密度和节约能源等因素,选择烧结温度1200 ℃、保温时间4 h、升温速率5 ℃/min。     

重介质旋流器SiC陶瓷衬里及其力学性能的研究

为探索制备高性能的重介质旋流器SiC耐磨衬里,制备了不同β-SiC添加量、不同烧结温度的SiC陶瓷试样,从体积密度、抗弯强度、维氏硬度、显微结构四个方面对试样进行了比较和分析。试验结果表明:当烧结温度为2 220℃,β-SiC添加量为10%时,烧结体体积密度、抗弯强度和维氏硬度最高,分别达到3.128 g/cm3、399.6 MPa和27.5 GPa。     

烧结工艺参数对金属注射成形In713C合金力学性能的影响

对采用水气联合雾化制备的In713C高温合金粉末进行注射成形,系统研究了烧结温度及保温时间对合金的密度、硬度及抗拉强度等性能的影响.结果表明:随着烧结温度的提高和烧结时间的延长,试样的密度、硬度及抗拉强度先升高后降低;在烧结温度为1290℃、保温时间3h的最佳烧结条件下,注射成形In713C合金试样的密度为7.82g/cm3、硬度43.6HRC、抗拉强度1056 MPa、屈服强度775 MPa、延伸率7.6%.     

Current situation and future trend of China rare earth luminescent material industry

<正>Rare earth luminescent material is one of the most important application sectors of rare earths.China enjoys the exceptional advantage to develop rare earth luminescent material for its abundant rare earth resources.After several decades'endeavor,China's rare earth luminescent material industry,headed by rare earth phosphor for lamp and LED and high efficient rare earth energy-saving light source,has been gradually developed into a scale industry.China has become a major production base of rare earth phosphor for lamps and rare earth     

China rare earth market review

正June 1~10,2014Rare earth market remained weak.Quoted price of rare earth products was similar to that in May.There was no sign of recovery in downstream market.The market of NdFeB magnetic materials and phosphor was depressed.Catalyst,polishing powder and ceramic industries remained inactive.Demand from downstream industry was soft.Consumers purchased on their needs.Suppliers had strong intention to sell.Prices of rare earth products     

Annual Report analysis of Chinese rare earth-related listed companies in 2013

<正>Chinese rare earth-related listed companies have published their 2013 annual reports.It can be understood from their reports that production and operation activities of Chinese rare earth-related companies were still heavily affected by macro economy and industrial policies.They basically followed the steps of national economy.In 2013,world economy recovered slowly but the economy     

Market opportunities and challenges for rare earth polishing powder

正1.Status of rare earth polishing powder Rare earth polishing powder with high content of cerium oxide began to replace iron oxide for glass polishing and became one of the key materials in glass polishing process since 1940.Compared with traditional iron oxide,rare earth polishing powder has many advantages,such as fast polishing rate,high polishing quality and long service life.It can achieve good surface quality and improve operation conditions.For example,in lens polishing,the polishing work that cerium     

Baotou Research Institute of Rare Earths developed a new RE alloy preparation technology

正Pyrometallurgy Laboratory of Baotou Research Institute of Rare Earths had independently developed a new preparation technology of rare earth alloy for NdFeB.The alloy can remarkably enhance the coercivity of NdFeB magnet but also evidently reduce the production cost of the magnet.The new master alloy was prepared in the kA pilot-scale electrolytic cell by the independent technology.The rare earth master alloy can be used as the raw material for NdFeB.Compared     

Market and recycling of NiMH battery

<正>Market status and future trend of NiMH battery1.Global market of small NiMH battery Global market size of small NiMH batteries declined year on year since 2011.The trend will continue to 2018,at the rate of 5%to 10%annually.Demand for small NiMH batteries will be stable gradually.Many electrical apparatuses are powered by the built-in lithium battery today,which is the main reason for the shrunk market of small NiMH batteries.But,for some products,small NiMH     

China rare earth market review

正September 1-10,2014 Affected by the National Day holiday,rare earth transaction was stagnant and the market showed a weak steady state.As there was no good news for downstream market,some products with flat demand would likely rally slightly for some time to     

2014 second batch of rare earth quota released

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矿用防爆轴流对旋主要通风机叶片ANSYS模态分析及应用

高效节能矿用防爆对旋主要通风机的叶片是主要通风机运行的关键部件,叶片在运行时不断受到气流的作用力,从而使叶片产生振动,当叶片振动的频率与叶片的固有频率接近时,容易产生共振从而导致叶片的断裂。一旦叶片断裂时,对主要通风机的安全运行产生致命的影响,从而导致矿山、化工等企业发生重大事故,将会产生不可估量的损失。基于有限元分析软件ANSYS,对高效节能矿用防爆轴流对旋主要通风机叶片进行模态分析及产生对应的六阶模态频率,对主要通风机叶片的运行频率、固有频率及产生的共振问题进行了原理分析,并且解决了叶片频率共振的问题,从而为主要通风机叶片结构设计提供理论依据,并对主要通风机叶片的安全运行提供保障。     

2013 NdFeB export analysis

<正>China totally exported nearly 24,000 tonsof NdFeB products during 201 3,including 18,825 tons of permanent magnet,valued USD 1.34 billion at an average price of 71.4 USD/kg;3,277 tons of NdFeB magnetic powder,valued USD 1 01 million at an average price of 30.9 USD/kg;1,334 tons of strip casting ribbon,with total export value of USD 74million at an average price of 55.3 USD/kg;and 586