挤压法制取银-石墨纤维型触头材料

本文介绍了一种新型的银-石墨纤维型触头材料。叙述了它的挤压、切片、脱碳等工艺。与常规工艺制取的材料相比,该材料不但物理性能、电寿命大为提高,而且保持了抗熔焊性好的优点。对于既要求有可靠的抗熔焊性又要求有较长电寿命的自动开关。是较为理想的触头材料。由于电寿命提高和触头尺寸减小,节银效果明显。     

AF1410超高强度钢硬质合金加工刀具的磨损机理

AF1410超高强度钢是具有难加工特性的新型结构材料,通过设计正交实验,研究涂层硬质合金刀具切削AF1410超高强度钢的切削力和刀具寿命,分析达到磨钝标准的硬质合金刀具前、后刃面的磨损形貌,以及刀具磨损机理。结果表明,刀具寿命随铣削深度和铣削速度增大而线性减小,随着每齿进给量和铣削宽度增加,刀具寿命下降趋势逐渐放缓甚至略有增加。刀具磨损分为3个阶段:磨合阶段—稳定磨损期—快速磨损阶段,在快速磨损阶段刀具磨损迅速增加,直到刀具失效。前、后刃面均发生刀具材料的严重剥离,同时粘结大量AF1410钢屑。刀具涂层失效的主要机理为磨粒磨损,刀具基体主要失效机理为扩散磨损和粘结磨损。     

新型Ag-5%C电接触材料的制备及其电弧磨损特性的研究

采用将高能球磨、还原剂液相喷雾化学包覆及粉末冶金相结合配以适量碳纳米管做为纤维增强体的工艺 ,制备出新型的Ag 5 %C(质量分数 )电接触材料。该材料具有优异的烧结致密性 ,烧结复压密度可达理论密度的 99.9%,而传统机械混粉工艺及国外发展的烧结挤压工艺同类材料仅能达到 97.0 %～ 98.4%;其硬度达到 64 5MPa ,大大超过同类触头 ;该新型材料由于C在基体中的均匀分布以及高烧结致密性 ,具有很好的导电性能 ,其电导率达到了 3 8 0m·Ω- 1 ·mm- 2 ,远超机械混粉工艺而接近烧结挤压工艺。经由ASTM触头材料试验机进行电磨损分断对比试验 ,发现与常规机械混粉同类触头相比 ,该材料同等条件下电弧磨损量小得多 ,且具有优异的电弧磨损特性 ,其电弧磨损量随分断次数呈指数小于 1的指数函数规律上升 ,即到分断后期其材料损耗量趋于稳定 ,有效抑制了触头分断电涡流磨损现象 ,这种优异的电弧磨损特性对于提高其材料耐电弧磨损性能具有重要意义。该材料有望成为一种可替代烧结挤压和机械混粉同类材料的新型Ag/C触头材料     

Ag-Fe_7铆钉制造工艺

CJ10系列接触器,过去使用纯银触头,不仅体积大,耗银量大,且抗电磨损性能差。自七十年代起,国内开始研究用于CJ10系列接触器的触头材料。AgFe7触头材料是其中之一种.经过长期使用证明,对     

QJ—01型摩托车电起动继电器触头的研制

受摩托车配套企业改脚踏起动为电起动的委托,我们对电起动继电器的“心脏”——触头部件进行开发研制。 1 触头材料的研制继电器触头是摩托车电起动系统中的关键部件,其性能的好坏直接影响到起动器的使用寿命。由于摩托车起动频繁,触头上瞬间电流较大,容易积聚热量。工作环境比较恶劣,用紫铜或普通钢合金无法胜任,必须研制一种     

真空常温下空间用铜基粉末冶金摩擦材料的摩擦学行为及可靠性寿命

在真空常温下,对空间摩擦副进行大负荷服役条件(400 N)可靠性寿命摩擦循环试验,考察空间用铜基粉末冶金摩擦材料的摩擦磨损特性,探讨摩擦材料的可靠性寿命并揭示其摩擦磨损机理。结果表明:铜基摩擦材料在真空常温大负荷摩擦循环试验条件下,摩擦磨损过程可分成三个阶段:第一阶段(1~1 400次试验),摩擦因数由0.28增加到0.61,并趋于稳定,磨损机理以磨粒磨损为主;第二阶段(1 400~2 700次试验),摩擦因数稳定在0.61左右,磨粒磨损和粘着磨损并存;第三阶段(2 700次试验后),摩擦因数逐渐下降,磨损机理转变为较强的粘着磨损和疲劳磨损,材料表现为失效,整个试验过程中,摩擦因数稳定系数均高于0.9。研究表明,研制的铜基摩擦材料在真空常温条件下可满足转位机构和空间机械臂等的可靠性需求。     

真空开关用触头材料

综合介绍德国第１５届阿尔贝特－凯尔电接触研讨会报导的真空触头材料最新的研究进展。讨论集中在用模拟真空开关试验装置对钨基、碳化钨基、铜格等触头材料的分断能力、电弧烧损、截止电流的研究结果以及分析解释。     

智能框架断路器用触头材料

论述了应用于我国最新设计制造的智能框架断路器上的触头材料工艺研究试验，通过大量试验，制成了高性能预烧钨骨架银钨触头和银镍石墨触头。经大电流电弧烧损和电磨损模拟试验，确定了较佳的动静触头品种，经装机型式试验证明，采用ＡｇＷ５０／ＡｇＮｉ２５Ｃ２非对称配对触头，满足了新路器的各项性能指标，短路分断能力达３８０Ｖ，６５ｋＡ，６６０Ｖ，５０ｋＡ，并具有显著的节银效果。     

微合金元素对新型铜基合金触头的作用研究

将新型铜基合金触头材料应用在PR194汽车继电器的触头上,研究了新型铜基合金触头材料中微量的Ni,Mo,Co等合金元素对触头性能的影响。结果表明:Ni以稳定的第二相Ni3Ti均匀地分布在基体中,提高了触头的抗氧化能力和耐热能力;Mo以高熔点、高硬度的单相Mo颗粒稳定地存在于熔融体中,提高了触头材料的抗电弧侵蚀能力,并降低材料的电弧摩损;而Co富集在触头表面Mo质点相上,有利于提高电触头材料的耐电弧性能、抗粘结性以及耐磨损性能。而在阻性负载实验中形成的Cu,Ag固体相、Cu-Ni相提高了材料的灭弧能力,形成的颗粒状Cu,Ag,Ni氧化物使合金的抗材料转移能力得到提高。这些微量元素的加入显著提高了触头综合性能,使得该触头的接触电阻在试验前小于50 mΩ,进行寿命实验后小于100 mΩ,电气寿命达到1×105次,产品质量合格。     

碳纳米管增强纳米晶Ag-5% C电接触材料研究

通过高能球磨结合还原剂液相喷雾化学包覆技术，配以适量碳纳米管作为纤维增强体制备得到纳米晶Ag-5％C（质量百分含量）包覆粉。与常规Ag-5％C机械混粉相比，在相同粉末冶金工艺下制备的触头力学物理性能测试表明，该碳纳米管增强纳米晶Ag-5％C电接触材料各项性能均比机械混粉触头优异。该材料有望成为一种可替代烧结挤压和机械混粉同类材料的新型AG/C触头材料。     

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.