中国超细和纳米晶WC-Co硬质合金的研究开发概况

概述了我国超细和纳米晶W C-Co硬质合金的研究开发现状。我国在制备超细晶硬质合金100nm左右的纳米级粉末原料(W C,W C-Co复合粉末)的批量化生产技术及烧结过程中抑制W C晶粒长大等关键技术方面已取得重要进展,可批量生产0.4～0.6滋m级超细晶硬质合金。添加新型VC基二元晶粒生长抑制剂可实验室制备W C平均晶粒度70nm的纳米晶硬质合金并获得优异性能。在此基础上,对生产技术的重点方向进行研究开发,推动我国超细晶硬质合金向产业化发展的基础条件已趋于成熟。     

纳米硬质合金的研究进展

概述了纳米晶WC-Co硬质合金的研究开发现状与进展。重点介绍了纳米硬质合金粉末常用的制备方法和烧结技术。同时，对我国超细晶粒硬质合金工业化技术开发的重点方向提出了具体看法。     

超细硬质合金中添加抑制剂的研究进展

生产超细硬质合金的关键是粉末的制备和压坯的烧结，并且超细硬质合金在烧结过程中容易引起晶粒长大。有关研究表明在超细硬质合金中添加抑制剂可以有效地控制硬质合金中晶粒的长大。近几年以来国内外对超细硬质合金中添加抑制剂进行了大量的研究。所以，本文就超细硬质合金中添加抑制剂的作用机理、种类、方法，以及抑制剂对超细硬质合金组织和性能的影响进行了综述。     

超细WC-Co硬质合金研究综述

从超细WC-Co硬质合金的原料、晶粒长大抑制剂、制备工艺和过程机理等方面,综合评述了近年来国内外关于超细WC-Co硬质合金的研究成果。     

纳米/超细晶WC-Co类硬质合金的研究进展

制备纳米/超细晶WC-Co类硬质合金的两大关键因素是优质纳米/超细晶WC-Co复合粉末的制备和烧结过程中晶粒长大过程的控制。从纳米/超细晶WC-Co复合粉末的制备技术和纳米/超细晶硬质合金的烧结技术两方面,综合评述了近年来国内外的研究进展,并展望了纳米/超细晶硬质合金的发展前景和今后研究开发的重点。     

以紫钨为原料制备超细WC-Co硬质合金

超细硬质合金具有高硬度、高耐磨性等优异性能,保证超细硬质合金的晶粒度小而且均匀的一个关键因素就是以粒度细小、分布均匀的超细WC粉末为原料。超细WC粉末的制备过程中,常用的氧化物原料为蓝钨,以紫钨为原料的制备工艺报道较少。采用相同的工艺,分别以蓝钨和紫钨为原料制备出超细WC粉末,并采用相同工艺制备出超细硬质合金,对两种产品性能进行对比,发现以紫钨为原料制备出的超细硬质合金晶粒度小,强度和硬度高,具有较好综合性能。     

Co含量对超细YG类硬质合金结构及性能的影响

制备了不同Co含量的超细硬质合金YG6和YG8,通过对试样进行表面形貌观察和物理力学性能测试,研究了Co含量对超细YG类硬质合金力学性能及组织结构的影响。在超细硬质合金的表面采用CVD法制备了TiCN-Al_2O_3-TiN多层复合涂层,对涂层合金进行微观结构观察、硬度和切削性能测试,探讨不同Co含量合金制备的刀具的切削性能。实验结果表明:随着Co含量的增加,WC晶粒更致密,没有发生晶粒异常长大,硬质合金硬度略有下降,相对磁饱和强度和抗弯强度增加,断裂源较少。Co含量低的硬质合金刀具磨损更严重,切削性能下降,刀具失效快。     

超细/纳米硬质合金及晶粒长大抑制剂的研究

超细／纳米WC-Co硬质合金由于其优越的性能而获得更加广泛的应用,从而成为近年来各国政府研究学者及厂矿企业十分关注的热门话题。本文综述了国内外在超细／纳米硬质合金及晶粒长大抑制剂方面的研究进展。重点介绍了超细／纳米WC-Co复合粉末的制备技术和新的烧结工艺以及晶粒长大抑制剂的种类、添加方式和作用机理。     

烧结工艺对低Co超细晶硬质合金性能的影响

低Co超细晶硬质合金具有比常规的超细晶硬质合金更高的硬度、耐磨性、红硬性,在精密机械、加工刀具、特种耐磨材料及零件、拉拔模具等领域有其独特的优势和广泛的应用。本文以超细WC粉和球形Co粉为原料,采用真空烧结或低压烧结制备低Co超细晶硬质合金。采用低压烧结技术可成功制备出硬度为2110 HV30,矫顽力为55.7 kA/m,抗弯强度为2 250 MPa的低Co超细晶硬质合金。采用SEM、金相显微镜、维氏硬度计、矫顽磁力仪、材料实验机等研究烧结工艺对合金显微组织和物理机械性能的影响。结果表明:提高烧结温度或采用低压烧结,可以使低Co超细晶硬质合金中的孔隙度减少,强度提高。低压烧结制备的合金晶粒度大于真空烧结制备的合金晶粒度,但是采用真空烧结制备的合金中易出现WC晶粒异常长大现象。     

超细晶WC-Co硬质合金用纳米钴粉的研究现状与展望

粘结剂原料钴粉在制备超细晶WC-Co硬质合金中的作用至关重要.采用超细/纳米级粒度的球形钴粉不仅可以降低合金的烧结致密化温度从而抑制WC晶粒异常长大,同时能够减少球磨混合时间、改善合金中的钴相分布,有助于获得高性能的超细和纳米晶WC-Co硬质合金.总结了近年来超细和纳米晶WC-Co硬质合金用钴粉的国内外研究开发状况,介绍了采用液相沉淀-氢还原法制备球形纳米钴粉的取得的实验成果,指出该法是生产超细和纳米晶WC-Co硬质合金用纳米钴粉的一种行之有效的新工艺路线.     

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.