熔体吹气发泡法制备泡沫铝合金研究

泡沫金属是近年来发展起来的一种新型材料。文章采用熔体吹气发泡法制备出了孔径为5．0—8．3mm，壁厚为0．040—0．076mm，密度为0．19—0．40g／cm^3，孔隙率为85．2％—93．0％的Al—Si泡沫铝合金，并着重讨论了发泡温度、气体流量、SiC粉末体积百分含量对泡沫铝合金形成的孔径和壁厚的影响关系。     

粉末冶金发泡法制备泡沫铝工艺研究

泡沫金属是近年来发展起来的一种新型结构功能材料.采用粉末冶金发泡法制备出孔隙率为45%-85%、平均孔径＜5mm的多孔泡沫铝合金试样,并用极差分析法讨论了发泡温度、保温时间和发泡剂的状态对泡沫铝合金的孔隙率的影响,得到了最佳制备工艺条件.     

金属发泡微孔材料

金属发泡微孔材料是近年来发展的一种功能型多孔金属材料，它具有高孔隙度、重量轻、透气性好、消音、绝热和不燃烧等优点。多孔金属材料就孔径大小可分为三类：大于50pm的为粗孔材料，2～50pm的为中扎材料，小于Zpm的为微孔材料。孔隙率大于60％的称为高孔隙率材料。用常规的粉未冶金方法制造多孔金属材料难以达到高的孔隙度，但采用发泡和金属纤维烧结方法，孔隙率最高可达到98％，而它的比重仅为原来未发泡金属的1／7～1／50。多孔金属材料的孔隙率和孔径大小可根据选择的原材料以及制造条件加以控制。目前，国外一些厂家根据各种金属材…     

压制压力对多孔TiAl合金孔结构及过滤性能的影响

以Ti、Al混合粉末为原料，通过反应烧结制备TiAl金属间化合物多孔过滤材料，分析压制压力对孔隙率、最大孔径及渗透系数的影响。结果表明：随着压制压力从90MPa增加到375MPa时，总孔隙率呈“急剧减小-平缓减小-平缓减小-平缓减小”的变化趋势，开孔隙率呈“急剧减小-平缓减小-显著增大-急剧减小”的变化趋势，最大孔径呈“急剧减小-减小-减小-减小”变化，而渗透系数呈“急剧减小-平缓减小-平缓增大-急剧减小”的变化。综合考虑压制压力对孔隙率、最大孔径及渗透系数的影响，当压制压力为250MPa时，TiAl合金烧结坯具有较大的开孔隙率、较小的孔径和较大的渗透系数。改变颗粒之间的间隙大小及数量，从而影响反应造孔和孔隙长大，是压制压力影响孔隙率、最大孔径的机制。     

真空渗流铸造法制备泡沫镁合金材料的试验研究

用制备泡沫铝合金常用的NaCl作为填料，在脱溶过程中，由于氯离子对镁基体的严重腐蚀导致镁基体骨架完全溃散，最终得不到泡沫镁合金材料；采用MgSO4作为填料，镁基体被腐蚀的程度显著降低，制备出了孔隙率大于70％、孔径小于1．4min的泡沫镁材料，但存在发生爆炸的可能性，用CO2作保护性气体能抑制这种现象的发生。用泡沫铝和干砂作透气底板可获得形状完整且高度可控的泡沫镁合金。     

粉末烧结法制备多孔Ti-6Al-7Nb合金的工艺优化

以Ti粉、Al粉和Nb粉为原料,采用粉末烧结法制备多孔Ti-6Al-7Nb合金,利用正交试验考察了混料时间、压制压力、烧结温度、烧结时间对孔隙率的影响。结果表明,各因素对孔隙率的影响主次顺序为:烧结温度烧结时间压制压力混料时间。结合骨科植入所需材料的孔隙率和孔径分布情况确定最优工艺参数为:混料时间4 h,压制压力100 MPa,烧结温度1 100℃,烧结时间2.5 h,采用最优工艺制备的多孔Ti-6Al-7Nb孔隙率为32%,孔径尺寸集中分布于5~12μm范围。     

钛合金纤维多孔材料制备及压缩性能

为降低钛及钛合金制品的成本，以钛锭表面切削下来的钛屑（切削纤维）为原料，经过清洗、剪切、压制、高温约束烧结等工序制备成钛合金纤维多孔材料，观察材料微观结构，分析压制压力和孔隙率之间的关系，并研究烧结温度、纤维宽度、孔隙率对钛合金纤维多孔材料压缩性能的影响规律。结果表明，钛合金纤维多孔材料内部均为通孔，随着压制压力的增加，钛合金纤维多孔材料的孔隙率随之降低。纤维宽度为2 mm，孔隙率为56.0%，烧结温度为1200℃条件下制得的钛合金纤维多孔材料平台应力达17.34 MPa。本文实现了原材料零成本制备钛合金纤维多孔材料，可用于阻尼减振、冲击防护等领域。     

浅析造孔剂含量控制对生物多孔钛材的影响

以碳酸氢铵为造孔剂,TiH_2粉为原料采用粉末冶金法,经过粉末混合、粉末压制、脱脂制备生物多孔钛材。研究碳酸氢铵(质量分数:0%、10%、20%、30%)对制备生物多孔钛材的孔隙率、孔径分布和屈服强度的影响。结果表明,碳酸氢铵在10%时,多孔钛孔隙率为32.4%,100~200μm的孔径约占面积总量的80%以上,屈服强度为208.1 MPa。     

粉末烧结溶解法制备多孔镍及其结构特性

为了制备镍多孔过滤材料,本文以镍粉为原料,以K2CO3为造孔剂,采用烧结溶解法制备了不同孔隙率镍多孔试样。本文讨论了造孔剂体积分数、压坯压力、烧结温度对样品孔隙率、孔径和透气度的影响,以及孔隙率与抗压强度的关系。研究表明:当造孔剂添加量在10%～40%时,样品孔隙率θ为27. 8%～52. 4%。当压坯压力在100～400 MPa时,随压力增大样品孔隙率、孔径和透气度均降低;烧结温度在1000～1250℃时,随烧结温度升高,孔径和透气度先增大后缓慢降低,在1150℃出现峰值。当造孔剂体积分数为30%,压制压力200 MPa时,烧结温度为1150℃时,所制备多孔镍孔隙率为40. 56%,最大孔径为26. 7μm,透气度255. 01 m3·(h·kPa·m2)-1,抗压强度为24. 12 MPa。     

泡沫铝制备工艺的试验研究

用TiH_2作发泡剂,采用粉末冶金工艺研制出了孔隙率达60％以上,密度在0.9g/cm~3以下的泡沫铝金属材料。试验结果表明:采用本工艺可制备各种形状和规格的泡沫铝,其孔径大小、分布和孔隙度可调控。这种方法制备的泡沫铝具有较好的机械阻尼、吸能减震、吸声隔声和电磁屏蔽性能。     

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.