复合电镀制备WC@W-Cu复合材料的组织与性能

W-Cu复合材料因具有低膨胀系数、高强度及较好的导电导热性能而广泛用作电子封装、电极、电触头和炮弹的罩壳等材料。W-Cu复合材料传统制备方法在致密化、微观组织的均匀性等方面难以兼顾,导致材料的导电导热性能不足,难以满足现代电子工业的要求。本研究以W粉及W粉表面碳化得到的WC@W粉为原料,采用复合电镀技术制备了W-Cu和WC@W-Cu复合材料。结果表明,W-Cu复合材料表面粗糙,微观组织存在孔洞,而WC@W-Cu复合材料晶粒细化,微观结构组织均匀、致密。WC@W-Cu复合材料的W含量(质量分数)为43.6%,硬度(HV)达2050 MPa,相对密度为99.3%,电导率可达54.6MS/m。采用WC@W纳米粉,电镀制备的WC@W-Cu复合材料不仅增加了W含量,明显提高了硬度,而且在相对密度和导电性方面也优于W-Cu复合材料。     

AlN覆钨对AlN/W-Cu复合材料组织和性能的影响

采用溶胶凝胶法对AlN粉体进行表面覆W后，将其与适量W粉混合，经压制、预烧结，制得多孔AlN/W骨架，再熔渗Cu后制备出不同AlN含量(0～8%)的AlN/W-Cu复合材料。考察了AlN含量对于烧结体微观组织、力学性能和热学性能的影响，并与由未覆钨AlN粉体制备的AlN/W-Cu复合材料进行对比。结果表明，采用溶胶凝胶法可在AlN颗粒表面均匀制备覆W层，其界面结合良好。覆钨AlN/W-Cu复合材料的相对密度、硬度、抗拉强度以及热导率均优于未覆钨AlN/W-Cu复合材料的。AlN/W-Cu复合材料的相对密度、抗拉强度及热导率随AlN含量的增加而降低，而硬度随AlN含量的增加而上升。当AlN含量为2%时，覆钨AlN/W-Cu复合材料的综合性能最佳，相对密度达到97.69%，显微硬度达到277HV，热导率达到205.54 W/(m·K)。     

活化烧结制备W-Cu复合材料及其性能

研究添加元素Ni对W-Cu复合材料组织和性能的影响。利用预混粉、机械球磨和活化液相烧结法制备不同Ni含量W-Cu复合材料,采用电子扫描显微镜、X射线衍射仪、激光导热仪等对复合材料的显微组织、物相、热导率、热膨胀系数和硬度进行检测与分析。结果表明:当W-Cu复合材料中不添加Ni元素时,W颗粒团聚形成闭合孔隙,液相Cu无法有效填充孔隙,导致W-Cu组织分布不均匀。随着Ni含量逐渐增加,钨颗粒尺寸不断增大,Cu相将W颗粒包覆;当Ni含量增至5%时,Cu相分布呈网状结构,复合材料组织的均匀分布。在性能方面,随着Ni元素含量的增加,W-Cu复合材料的致密度从83.91%提高到95.59%,硬度由229HV提升至304HV,各温度下热导率和热膨胀系数均有所下降。     

W-Cu复合材料制备新技术与发展前景

W-Cu复合材料具有热膨胀系数低、导电性好、导热性好、高熔点、高硬度以及良好的抗电弧烧蚀性能,在机械加工、电气工程以及电子信息领域被广泛用作电极材料、电接触材料、电子封装材料及靶材等越来越受到国内外的关注。传统粉末冶金方法制备的W-Cu复合材料致密度低、组织结构粗大且均匀性差,严重影响材料性能。采用纳米复合新技术制备的W-Cu复合材料具有很大的技术优势:粉末纳米化使得粉末的烧结活化能大大降低,其烧结活化能在1 420℃时仅为42.1 kJ/mol和29.1 kJ/mol,远低于纯W相同温度范围内的587.9 kJ/mol,同时纳米复合使得W与Cu发生了固溶,从而使得复合粉末表现出良好的烧结活性。采用纳米复合制备的细晶W-Cu复合材料具有非常优异的综合性能,其原因在于经烧结后获得高的致密度和组织结构均匀细小。     

真空热压烧结W(50)/Cu-Al_2O_3复合材料的性能研究

采用真空热压烧结工艺制备W(50)/Cu-Al2O3复合材料,观察了其显微组织,测试了其致密度、硬度、抗弯强度和导电率。结果表明:W(50)/Cu-Al2O3复合材料组织致密;致密度和硬度优于Cu-50%W,致密度可达99.8%,显微硬度达135 HV。而导电率为46%IACS,略低于W-50%Cu复合材料。抗弯强度为291.3 MPa,弥散铜钨合金室温弯曲断裂主要以弥散Cu相的撕裂为主,伴随有W-Cu界面的分离和部分W晶粒的解理断裂。     

高性能钨-铜复合材料制备与性能研究进展

钨-铜(W-Cu)复合材料具有优异的物理和力学性能,如良好的导电导热性、较低的热膨胀性、高硬度和强度,被广泛应用于电力、电子、核电工业、军工与航天等领域.W和Cu元素的熔点相差较大且互不反应,无中间相析出,因此粉末冶金是W-Cu复合材料制备的传统方法.近些年来,为获得更高性能的复合材料,一些新的方法被运用于制备W-Cu...     

热压温度对石墨烯铜基复合材料组织及性能的影响

采用粘结混粉、真空热压烧结的方法制备石墨烯铜基复合材料,研究了不同热压温度对石墨烯铜基复合材料物相与组织形貌、致密度、导电性、导热性及力学性能的影响。结果表明:石墨烯在铜基体中实现了均匀分散,且两者界面结合紧密。随着热压温度的升高,复合材料的致密度、导电性、导热性及力学性能均先升高后降低。当热压温度为900℃时,制备的复合材料致密化高,孔隙率低,综合性能最优异,复合材料的致密度、导电率、导热率、显微硬度、屈服强度、抗拉强度分别为98.2%、93.2%IACS、411.0 W·m-1·K-1、85.3 HV、128.8 MPa、253.8 MPa。     

Structure and Properties of W-Cu/AlN Composites Prepared via a Hot Press-Sintering Method

采用高能球磨技术制备W-30%Cu（质量分数）纳米晶粉体,再通过球磨混粉的方法添加不同质量分数的纳米AlN颗粒,然后采用热压烧结法得到W-30Cu/x%AlN复合材料。研究并比较了纳米AIN的加入对材料组织结构、物理以及力学性能的影响。结果表明,W-30Cu/x%AlN复合材料都有较致密和均匀的组织结构,AlN的添加,细化了烧结体中W颗粒;纳米AlN颗粒的添加提高了复合材料的硬度,但是随着A1N纳米颗粒含量的增加,基体晶界上的增强相颗粒分布过多,而使材料的抗弯强度有所下降;少量纳米AlN颗粒(≤1%)的添加有利于W-Cu复合材料的热导率提高,随AIN添加量的增加,复合材料的电阻率升高,电导率下降。     

粒度配比法制备近全致密W/Cu20复合材料

选用A、B两种不同粒度的W粉,调节A、B钨粉的比例,并与Cu粉直接混合,配制成W/Cu20(质量分数%,下同)混合粉末,经热压制备了近全致密的W-Cu复合材料。显微组织观察表明,随着小粒度W粉配比的增加,大W颗粒形成的孔隙逐渐减少,而小W颗粒形成的孔隙逐渐增加。当W粒度配比为80%A+20%B时,形成较为致密的堆积结构。在合适的工艺条件下(烧结温度1060℃、压力85MPa、保温3h),所制备的W/Cu20复合材料其相对密度达到98.6%,Cu相沿大W颗粒和小W颗粒的边界呈现网状分布。     

W-Ni/Yb2O3复合材料的制备及烧结性能研究

本文首先采用化学镀获得Ni-Yb2O3复合粉体,然后通过机械球磨制备了不同成分的W-（0.2、0.5、1、2）wt% Ni/Yb2O3复合粉末,最后在1600℃下烧结3h获得了W-Ni/Yb2O3复合材料。采用场发射扫描电子显微镜(FE-SEM)研究分析了Ni-Yb2O3复合粉体形貌、W-Ni/Yb2O3复合材料表面形貌。测定了W-Ni/Yb2O3复合材料相对密度、显微硬度和热导率。实验结果表明,W-Ni/Yb2O3复合材料的相对密度和显微硬度随着Ni-Yb2O3含量增加而增加,Ni-Yb2O3的加入促进了钨基材料的烧结致密化;同时,添加Ni-Yb2O3复合粉使钨基材料的晶粒得到细化,但对钨基材料导热性起到降低的作用。     

Electrical breakdown characteristic of a Ce-doped W-Cu contact material

W-Cu composite powder doped with Ce (1.5 wt.%) was prepared by mechanical alloying (MA), and the W-Cu contact material was fabri-cated by hot pressing sintering in an electrical vacuum furnace. The microstructure, electric conductivity, hardness, and breakdown voltage of the Ce-doped W-Cu alloy were measured and compared with a conventional W-Cu alloy prepared by powder metallurgy. The results show that microstructural refinement and uniformity can improve the breakdown behavior and the electric arc stability of the Ce-doped W-Cu contact material. Also, the Ce-doped W-Cu contact material shows the characteristic of spreading electric arc, which is beneficial to electric arc erosion.     

Characterization of W80Cu20 alloy sheet prepared by hot-rolling

Multi-pass hot-rolling technique was used to fabricate W80Cu20 alloy,and its properties were characterized in this paper.Results show that the W-Cu alloy sheets with a thickness of 0.5 mm and a relative density of99.87%can be successfully made using this new technique at 800℃.In hot-rolling process,Cu phases are closely surrounded by W particles under the rolling stress to form a network microstructure,thus making significant increase in electrical and thermal conductivity up to53.00%and 24.44%,respectively.Transverse and longitudinal hardness of the W–Cu sheets significantly increase due to the enhanced densification and deformation strength.Similar to that of the raw materials,three fracture types were observed in the hot-rolled materials,i.e.,ductile fracture of Cu binding phases,trans-granular fracture of W phases,and W–W interfacial fracture.     

Influence of additives and concentration of WC nanoparticles on properties of WC−Cu composite prepared by electroplating

The effects of additives (polyethylene glycol (PEG), sodium dodecyl sulfate (SDS)) and WC nano-powder on the microstructure, relative density, hardness and electrical conductivity of electroplated WC−Cu composite were investigated. The preparation mechanism was also studied. The microstructure of samples was analyzed by XRD, SEM, EDS, TEM and HRTEM. The synergistic effect of PEG and SDS made the WC−Cu composite more compact during the electroplating process. The hardness of WC−Cu composites increased with the increase in WC content, while the electrical conductivity decreased with the increase in WC content. The density of samples tended to increase initially and then decreased with increase in the additive content. When the electroplating solution contained 10 g/L WC nano- powder, 0.2 g/L PEG and 0.1 g/L SDS, the WC−Cu composite exhibited hardness of HV 221 and electric conductivity of 53.7 MS/m. Therefore, the results suggest that WC−Cu composite with excellent properties can be obtained by optimizing the content of additives and WC particles.     

Fabrication and properties of a novel ZnO/Cu composite

A novel Cu matrix composite reinforced by ZnO particulates has been prepared via a powder metallurgy technique. Resultant materials were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS) techniques. Microscopic observation exhibits a homogenous distribution in Cu matrix of ZnO particulates, and the analysis of bending fracture surface reveals a relative good interfacial bonding. Performance tests indicate that the hardness of the composite has been significantly enhanced, while the electrical conductivity remains at a fairly high level. Both ZnO content and fabrication processes can obviously affect the properties of the composite. With increasing the mass fraction of ZnO, the relative density and electrical conductivity decrease monotonously, while the hardness exhibits non-monotonous change. Repressing and re-sintering process lead to increased relative density, electrical conductivity and hardness. While the process of plastic deformation results in further increased density and hardness, but decreased electrical conductivity.     

Ti2SnC质量分数对铜基复合材料显微组织及性能的影响

为了制备强度高导电性能优异的铜基复合材料,以三元层状导电陶瓷Ti2SnC作为增强相,通过直热法粉末烧结技术制备Ti2SnC/Cu复合材料。研究了在烧结温度800℃、成型压力45MPa、保温时间30min、真空度50Pa的成型条件下,质量分数分别为0、5%、8%、10%的Ti2SnC增强相对复合材料的显微结构、硬度、抗拉强度、抗冲击韧性和导电率等性能的影响。结果表明:Ti2SnC的质量分数为5%时,综合性能最优,致密度和导电率分别达到94%、39%IACS,抗拉强度248MPa,硬度为88.7HBS,可适用于受电弓滑板。     

金刚石粒径及含量对超音速激光沉积金刚石/Cu复合涂层微观结构及性能的影响

目的研究不同金刚石粒径及含量对超音速激光沉积金刚石/Cu复合涂层微观结构及性能的影响。方法利用超音速激光沉积技术制备金刚石/Cu复合涂层。采用扫描电镜和摩擦磨损测试对涂层的显微组织结构和磨损性能进行了分析,用激光闪烁法测量复合涂层的热导率。结果金刚石均匀分布在复合涂层中,原始粉末中金刚石体积分数从30%增加到50%时,复合涂层中金刚石颗粒的面积占比仅从14.01%升至16.79%,远低于金刚石颗粒在原始粉末中的含量。400目金刚石/Cu复合涂层的平均热导率为296 W/(m·K),摩擦系数为0.551;800目金刚石/Cu复合涂层的平均热导率为238 W/(m·K),摩擦系数为0.545。结论原始粉末中金刚石配比的增加并未对复合涂层中金刚石含量的提升有显著作用。金刚石/Cu复合涂层的热导率随着增强相颗粒含量的增加而降低,随着增强相颗粒粒径的增大而提高。不同粒径金刚石颗粒的添加能显著降低Cu涂层的摩擦系数,且小粒径金刚石颗粒的添加使复合涂层的摩擦系数更低和更稳定,从而使其具有更小的磨损量和磨痕宽度,表现出较优的耐磨损性能。     

添加剂对新型AgTiB2触头材料微结构和性能的影响

以乙二胺为溶剂采用微波溶剂热法合成铜铟镓硒(CIGS)粉体,研究了反应温度、表面活性剂对合成产物物相及形貌的影响.采用X射线衍射仪、扫描电镜及X射线能谱仪对产物的物相、形貌及组成进行表征.结果表明:在反应温度为230℃(反应时间为2 h)条件下可以获得物相单一,颗粒尺寸较小的CIGS粉体.在基准溶液中加入表面活性剂十二烷基硫酸钠(SDS)后对合成产物形貌有明显改善作用,粉体分散性较好,呈圆球状且粒径较小,为100～200 nm.