机械活化-放电等离子烧结FeAl/Al2O3复合材料

利用机械活化-放电等离子烧结的方法,将Fe-Al-Al2O3粉末经机械活化后快速烧结,得到致密且晶粒细小的FeAl/Al2O3,块体复合材料.研究表明,在球粉质量比13:1、转速170r/min、球磨时间25h的球磨条件下,Fe-40%(原子数分数)Al-10%(质量分数)Al2O3粉体中的纳米级Al2O3颗粒,在细化和活化Fe、Al金属粉末的同时,还能有效地阻止金属粉末在烧结前合金化生成金属间化合物.在烧结压力40MPa、烧结温度1 050℃、加热时间15min、保温时间10min的工艺条件下,制备的FeAl/Al2O3复合材料的相对密度达96.4%.     

机械合金化制备纳米晶Fe-Si合金的研究

采用Fe-6．5％Si合金粉与Si-22％Fe合金粉末，经机械合金化制备了Fe-13．95％Si固溶体合金。由碰撞频率、速率与球磨工艺条件的理论关系推导出了球料比的最佳值。利用XRD、SEM和EDX手段对球磨后的Fe—Si粉体进行了结构、形貌及成份表征。结果表明：混合粉体球磨12h可实现机械合金化，合金化的粉体为α—Fe（Si）过饱和固溶体，颗粒尺寸为0．5～15μm，显微组织为纳米晶结构，平均晶粒尺寸约为18nm。     

包裹型SiO2/Al复合粉体的制备及烧结性能研究

为了克服金属陶瓷两相分布不均、界面不润湿和难以烧结致密等难题,采用球磨技术将增强相均匀包裹在基体材料表面,研究包裹型SiO₂/Al复合粉体的球磨制备工艺及其烧结性能,提高金属陶瓷的综合性能。结果表明,随着球磨时间的延长,SiO₂/Al复合粉体的比表面积先增大后减小,球磨6 h获得的复合粉体比表面积最大,达到8.1 m2·g?1。随着球料比的增大,SiO₂/Al复合粉体的比表面积先增大后减小,说明SiO₂包裹在Al粉表面的量呈现先增多再减少的趋势。随着球磨转速的增大,SiO₂/Al复合粉体比表面积先增大后减小。随着烧结温度的提高,SiO₂/Al金属陶瓷表面硬度先增高后降低,在烧结温度为900 ℃时,SiO₂/Al金属陶瓷的表面硬度达到最高。球磨时间为6 h,球料比为2:1,球磨转速为360 r·min?1,烧结温度900 ℃可以获得性能较佳的SiO₂/Al金属陶瓷。     

专利信息

正一种零膨胀超细纳米晶Mn3(Cu0.5Ge0.5)N块体材料的制备方法本发明公开了一种零膨胀超细纳米晶Mn3(Cu0.5Ge0.5)N块体材料的制备方法,属于新型功能材料和粉末冶金技术领域。首先以Mn2N0.86粉、Cu粉和Ge粉为原料,利用放电等离子烧结方法,合成出微米级晶粒尺寸的Mn3(Cu0.5Ge0.5)N块体材料;然后进行球磨处理,使球磨后的粉末具有完全的非晶结构;最后,将球磨后的粉末在氮气保护下进行放电等离子烧结,获得具有零膨胀     

基于正交设计与BP神经网络优化制备纳米WC-MgO复合粉末

采用高能球磨对WC粉和MgO粉进行球磨制备纳米WC-MgO复合粉末。为获得晶粒尺寸较小的纳米复合粉末,运用正交实验设计结合BP神经网络优化球磨工艺参数。以磨球直径、球磨转速和球料比为正交实验设计因子,每个因子各取4个水平,以WC-MgO复合粉末的晶粒尺寸为目标因子,编制3因素4水平正交设计表。结合BP神经网络强大的自学习和函数拟合功能,以正交设计表中3因素为网络输入层,以晶粒尺寸为网络输出层,建立BP神经网络优化模型,并通过该模型进行预测和优选,得到最佳的高能球磨工艺参数。即磨球直径10mm、球磨转速324r/min、球料比6.45:1。此时,WC-MgO复合粉末的晶粒尺寸为18.51nm,与预测值18.23nm的相对误差为1.51%。     

W-10%TiC复合材料的制备与力学性能研究

采用高能球磨手段制备了W-10%TiC(质量分数, 下同)纳米复合粉体, 并采用热压方法烧结成致密块体, 研究了高能球磨、烧结温度、烧结时间及烧结压力对复合材料致密度和力学性能的影响. 结果表明: 高能球磨后, 复合粉体的颗粒形状近似球形, 粒径均匀, 平均粒径为100 nm, 并且纳米复合粉体的烧结温度大大降低, 其原因是粉体的颗粒细小、扩散系数高、表面能高等性质及球磨过程中少量Fe, Ni杂质的引入. 对所制备纳米粉体而言, 较合适的烧结工艺为: 1700 ℃, 30 Mpa压力下烧结60 min, 在此工艺条件下制备的复合材料的致密度达到98.4%, 抗弯强度和断裂韧性分别达到: 681 Mpa, 6.24 Mpa·m1/2.     

球磨时间对放电等离子烧结合成Ti_3SiC_2纯度的影响

本文采用原料配比为3Ti/Si/2C/0.2Al(摩尔比)的单质混合粉体为原料,进行机械合金化(MA)和随后的放电等离子烧结(SPS),以制备高纯Ti3SiC2陶瓷,研究了球磨时间对放电等离子烧结制备Ti3SiC2的影响。结果表明,机械合金化混合粉体后,粉体颗粒明显细化。球磨10h,单质混合粉体会发生化学反应,生成TiC,Ti3SiC2混合粉体。继续球磨至20h,生成物混合粉体会显著细化。球磨时间对SPS烧结合成Ti3SiC2有显著的影响。球磨10h,即反应刚刚完毕,最有利于SPS合成致密高纯的Ti3SiC2,球磨时间较短(5h),对Ti3SiC2陶瓷的烧结促进作用不显著,而反应后继续延长球磨时间至20h,会降低烧结体中Ti3SiC2的纯度。采用球磨10h的粉体为原料,经850℃放电等离子烧结可获得纯度高达96%(质量分数,下同)的Ti3SiC2疏松块体,烧结温度提高到1100℃,可获得纯度为99.3%、相对密度高达98.9%的TiSiC致密块体。     

球磨工艺对MoSi_2机械合金化过程的影响

通过对Mo、Si混合粉末的机械球磨 ,研究了球磨工艺对MoSi2 机械合金化过程的影响。结果表明 ,在球料比均为 5∶1、10∶1和 30∶1的情况下 ,采用硬质合金球体球磨Mo、Si混合粉末比采用不锈钢球体球磨易于生成MoSi2 (t) ;而在球料比为 2 0∶1时 ,采用硬质合金球体球磨Mo、Si混合粉末与采用不锈钢球体球磨生成MoSi2 (t)的时间相当。     

合金元素对机械合金化和放电等离子烧结Ti-Nb基合金显微组织的影响

β-Ti型结构的钛基材料在生物材料领域具有广泛的应用前景。本文采用机械合金化法和放电等离子烧结制备β-Ti型Ti-Nb基合金,研究不同Nb,Fe含量对合金显微组织及力学性能的影响。利用扫描电镜(SEM)、X射线衍射仪(XRD)和透射电镜(TEM)等手段分析合金的显微组织变化情况。结果表明:机械合金化过程中,粉末的平均粒度减小,当球磨时间超过60 h时粉末易发生团聚。当球磨转速为300 r/min,球料比为12:1,Ti和Nb的质量分数分别为64%和24%时,球磨100 h后制备的粉体材料中具有一定体积的非晶相。该粉末在1 000℃下通过放电等离子烧结(SPS)制备具有均匀细小的球状晶粒组织的Ti-Nb合金,其强度、伸长率和弹性模量分别为2 180MPa,6.7%和55 GPa。通过控制Nb,Fe的含量,可以促进β-Ti相形成,获得高强度和低杨氏模量的Ti-Nb合金。     

球磨工艺对Al2O3/Mo复合材料组织的影响

针对原位自生Al2O3增强钼基复合材料晶粒较大的问题,采用溶胶-凝胶与高能球磨相结合的方法细化复合材料晶粒,并利用SEM、XRD对不同球磨工艺所制备Al2O3/Mo复合粉末及复合材料的组织进行了观察和分析。结果表明:随着球磨时间的延长,Al2O3/Mo复合粉末颗粒由球状变为层片状再成为细小的球状,颗粒大小由约1.5μm细化为约500nm,其中的钼晶粒不断细化;高球料比所得粉末的分散性和破碎细化程度较好;转速提高使得粉末颗粒的尺寸均匀程度降低,且伴有结块现象,不利于粉末的细化。在球料比5∶1、转速300r/min、球磨时间60h条件下获得的复合粉末,经压坯烧结可制备出Al2O3颗粒为纳米级的钼基复合材料。     

China's Major Non-ferrous Metals Imports & Exports

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Zinc Production by Province in 2014

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80% of Chinese Firms Purchasing Overseas Mines Ended up in the Red

<正>Minmetals Resources acquired the world’s largest copper mine under construction for USD5.85 billion.One after another,listed companies Jien Nickle,China Molybdenum and Chihong Zinc and Germanium raised money to get involved in overseas mining projects…SOEs and private enterprises are engaged in a frenzy of overseas mine purchasing.A reporter with Economic     

Copper Processing Profit Dropped Sharply,Copper Consumption Will Face Impact in the Second Half of the Year

正Judging from China’s copper consumption field,the biggest consumption unit is electric power,which accounts for 47%of total consumption;it is followed by light industry sector,including household electrical appliance,machinery,durable goods and hardware etc,which accounts for 22%of total consumption;followed by transportation field,     

Central Geological Prospecting Fund Newly Added 16.47 Million Tonnes of Bauxite in 2013

正In 2013,the Central Geological Prospecting Fund(CGPF)Project newly discovered 15 ore fields,including 3 large above ore fields,and 5medium sized ore fields.The reporter learned from the recently published"Annual Report of Central Geological Prospecting Fund Project(2013)"that,from 2006 to 2013 the CGPF     

Manufacturers of Copper Tube for Central Air Conditioner Use Face Mounting Pressure in the Final Quarter of the Year

正This year,the investment growth rate of real estate industry continued to slow down,sold area of commercial housing also dropped significantly,which brought huge pressure to the domestic air conditioning manufactures.In the first half of the year,by relying on high growth in national financial expenditure,along with investment in public infrastructure     

Xinjiang Ranks No.1 in Production of Primary Aluminum in China

正Kang Yi,Honorary Chairman of China Nonferrous Metals Industry Association,said recently at the Forum on Development of the Non-ferrous Metals Industry in Central and Western China held in Zhengzhou that,as more and more electrolytic aluminum factories in Xinjiang came into operation,the electrolytic aluminum output of Xinjiang had reached2,275,000 tons in the first 7 months this year,     

Shenhuo Coal Industry and Electricity Power Completed800,000 t/a Aluminum Project in Xinjiang

正"Xinjiang project has been completed according to schedule,but total completion and total start of production are two different concepts,after completion it still needs a gradual process of reaching production target."On the morning of November 3,Shenhuo Coal Industry and Electricity Power told investors the above statement on the investor interaction platform.     

Guangdong Metal Transaction Center has Become the Second Largest Precious Metal Transaction Platform Nationwide

正The reporter learned from Guangdong Province Precious Metal Transaction Center that in 2013the Center maintained healthy development momentum,and had become the second largest precious metal transaction platform in China in terms of market size;currently Guangdong is quickening steps of financial innovation for the Center,aiming to build a transaction center with international core competitiveness.     

Seven Rare Earth Projects Involving Close to 3 Billion Yuan Investment Landed In the HighTech Zone

正On May 22,Baotou Rare Earth Industry Cooperation Consultation MeetingProject Agreement-signing Ceremony was held in Ningbo,nearly 40 enterprises from Ningbo,Guangdong,Hunan,and Shanxi participated in project consultation.After multi-lateral communication,agreements were signed for a total of 7 rare earth projects successfully.