Electroless copper-phosphorus coatings with the addition of silicon carbide (SiC) particles

Cu-P-silicon carbide （SiC） composite coatings were deposited by means of electroless plating.The effects of pH values,temperature,and different concentrations of sodium hypophosphite （NaH2PO2·H2O）,nickel sulfate （NiSO4·6H2O）,sodium citrate （C6H5Na3O7·2H2O） and SiC on the deposition rate and coating compositions were evaluated,and the bath formulation for Cu-P-SiC composite coatings was optimised.The coating compositions were determined using energy-dispersive X-ray analysis （EDX）.The corresponding optimal operating parameters for depositing Cu-P-SiC are as follows：pH 9;temperature,90oC;NaH2PO2·H2O concentration,125 g/L;NiSO4·6H2O concentration,3.125 g/L;SiC concentration,5 g/L;and C6H5Na3O7·2H2O concentration,50 g/L.The surface morphology of the coatings analysed by scanning electron microscopy （SEM） shows that Cu particles are uniformly distributed.The hardness and wear resistance of Cu-P composite coatings are improved with the addition of SiC particles and increase with the increase of SiC content.

Finite element simulation of the micromachining of nanosized-silicon-carbide-particle reinforced composite materials based on the cohesive zone model

A finite element method based on the cohesive zone model was used to study the micromachining process of nanosized silicon-carbide-particle(SiCp) reinforced aluminum matrix composites. As a hierarchical multiscale simulation method, the parameters for the cohesive zone model were obtained from the stress-displacement curves of the molecular dynamics simulation. The model considers the random properties of the siliconcarbide-particle distribution and the interface of bonding between the silicon carbide particles and the matrix.The machining mechanics was analyzed according to the chip morphology, stress distribution, cutting temperature, and cutting force. The simulation results revealed that the random distribution of nanosized SiCp causes non-uniform interaction between the tool and the reinforcement particles. This deformation mechanics leads to inhomogeneous stress distribution and irregular cutting force variation.

Fabrication and densification enhancement of SiC-particulate-reinforced copper matrix composites prepared via the sinter-forging process

The fabrication of copper （Cu） and copper matrix silicon carbide （Cu/SiCp） particulate composites via the sinter-forging process was investigated. Sintering and sinter-forging processes were performed under an inert Ar atmosphere. The influence of sinter-forging time, temperature, and compressive stress on the relative density and hardness of the prepared samples was systematically investigated and subsequently compared with that of the samples prepared by the conventional sintering process. The relative density and hardness of the composites were enhanced when they were prepared by the sinter-forging process. The relative density values of all Cu/SiCp composite samples were observed to decrease with the increase in SiC content.

Microstructure and mechanical properties of SiC-particle-strengthening tri-metal Al/Cu/Ni composite produced by accumulative roll bonding process

In this study, a multilayer Al/Ni/Cu composite reinforced with Si C particles was produced using an accumulative roll bonding(ARB) process with different cycles. The microstructure and mechanical properties of this composite were investigated using optical and scanning microscopy and hardness and tensile testing. The results show that by increasing the applied strain, the Al/Ni/Cu multilayer composite converted from layer features to near a particle-strengthening characteristic. After the fifth ARB cycle, a composite with a uniform distribution of reinforcements(Cu, Ni, and SiC) was fabricated. The tensile strength of the composite increased from the initial sandwich structure to the first ARB cycle and then decreased from the first to the third ARB cycle. Upon reaching five ARB cycles, the tensile strength of the composite increased again. The variation in the elongation of the composite exhibited a tendency similar to that of its tensile strength. It is observed that with increasing strain, the microhardness values of the Al, Cu, and Ni layers increased, and that the dominant fracture mechanisms of Al and Cu were dimple formation and ductile fracture. In contrast, brittle fracture in specific plains was the main characteristic of Ni fractures.

Effect of Al2O3sf addition on the friction and wear properties of (SiCp+Al2O3sf)/Al2024 composites fabricated by pressure infiltration

Aluminum(Al) 2024 matrix composites reinforced with alumina short fibers(Al_2O_(3sf)) and silicon carbide particles(SiC_p) as wear-resistant materials were prepared by pressure infiltration in this study. Further, the effect of Al_2O_(3sf) on the friction and wear properties of the as-synthesized composites was systematically investigated, and the relationship between volume fraction and wear mechanism was discussed. The results showed that the addition of Al_2O_(3sf), characterized by the ratio of Al_2O_(3sf) to SiC_p, significantly affected the properties of the composites and resulted in changes in wear mechanisms. When the volume ratio of Al_2O_(3sf) to SiC_p was increased from 0 to 1, the rate of wear mass loss(K_m) and coefficients of friction(COFs) of the composites decreased, and the wear mechanisms were abrasive wear and furrow wear. When the volume ratio was increased from 1 to 3, the COF decreased continuously; however, the K_m increased rapidly and the wear mechanism became adhesive wear.

C/Ti/Cu interfacial reaction in SiCf/Cu composites

Continuous SiC fiber reinforced copper matrix （SiC~/Cu） composites were prepared by fiber coating method, and Ti6A14V interlayer was introduced as an interfacial modification coating to improve the interfacial bonding strength. The interfacial reaction characteristics were investigated by transmission electron microscopy （TEM）. The results show that nearly all the titanium atoms reacted with the carbon coating of SiC fibers to form two layers of TiC. Also, a thin copper layer that is sandwiched between these two layers was detected. No Ti-Cu interfacial reaction product was observed. The formation process of the interfacial reaction along with its mechanism was discussed.

铝酸盐体系中氧化时间对碳化硅颗粒增强铝基复合材料微弧氧化膜层的影响

[目的]探究氧化时间对碳化硅颗粒增强铝基(SiC_(p)/Al)复合材料微弧氧化膜层的影响。[方法]选用铝酸盐体系作为电解液,对SiC_(p)/Al复合材料进行微弧氧化处理,分析氧化时间对膜层组织结构、物相、厚度、粗糙度、结合力、电绝缘性及耐蚀性的影响。[结果]随着氧化时间延长,膜层逐渐变得连续均匀,厚度增加。若氧化时间过长,膜层会出现层叠现象,形成大尺寸微孔及裂纹,且生长速率越来越低。膜层结合力随氧化时间延长先增大后减小,在60 min时最大,达到39.85 N。氧化时间为10 min时,膜层的电绝缘性及耐蚀性最优,100 V和500 V电压下的绝缘电阻分别达到3.11×10^(12)Ω和1.41×10^(12)Ω,腐蚀电位为-0.6298 V,腐蚀电流密度为1.332×10^(-7)A/cm^(2)。[结论]SiC_(p)/Al复合材料表面微弧氧化膜层的连续性、均匀性及生长速率均与氧化时间有关。需选择合适的氧化时间,才能制备出连续、均匀且综合性能优异的膜层。

SiC复合陶瓷增韧研究现状

SiC陶瓷具有优良的性能,被广泛应用于各领域,但因韧性不足而制约其作为结构材料的应用,故提升其韧性已成为研究热点和焦点。因此,综述了颗粒、晶须、纤维和低维纳米材料(碳纳米管和石墨烯)等不同增强相增韧SiC复合陶瓷的研究现状,期望为今后SiC陶瓷的增韧研究提供参考。

有机硅单体合成用复合铜粉催化剂的研究

采用硅粉与氯甲烷,于直管式固定搅拌床反应器中合成甲基氯硅烷,通过计算二甲基二氯硅烷(M2)的选择性和硅转化率,评价3种复合铜催化剂的催化性能。结果表明,自产复合铜粉C的催化性能相对较佳,采用复合铜粉C的体系在整个反应期间的M2选择性均值为91.89%,硅转化率为59.24%。复合铜粉C具有更薄、更细、比表面积更高、松装密度更低、粒度更细的特点,有利于其在甲基氯硅烷合成反应中与硅粉形成更多的活性中心。

SiC粉末粒径及其预处理方法对Ni–SiC复合电镀层组织结构的影响

针对活塞杆高温、高压、高速运动的服役环境,提出对其表面进行Ni–SiC复合电镀,以提高活塞杆的耐磨损和耐腐蚀性能。研究了粉末粒径及其预处理方法对Ni–SiC复合镀层表面粗糙度、微观形貌和SiC微粒复合量的影响。结果表明,所得Ni–SiC复合镀层的外观均良好,微观组织均匀且SiC微粒弥散分布于其中,与45钢基体间结合良好、无缝隙。在SiC粉末预处理方法相同的情况下,随着SiC粒径由2μm增大到10μm,SiC的复合量呈现先缓慢后快速再缓慢增大的变化趋势。而在SiC粒径相同的情况下,表面活性剂十二烷基磺酸钠处理的SiC微粒在镀层中的复合量最高,无水乙醇处理的次之,盐酸处理的最低。

复合电铸制备Cu/SiC_p复合材料的工艺

采用复合电铸工艺制备碳化硅颗粒 (Si Cp)增强铜基复合材料 ,重点研究了添加剂、颗粒粒径、电流密度、施镀温度、搅拌强度等工艺参数对 Cu/ Si Cp 复合材料中 Si Cp 含量的影响 .结果表明 ,优化各工艺参数可有效促进 Si Cp 与铜离子的共沉积 ,提高复合材料中增强固体颗粒的含量 .在此基础上研究开发了一种可有效促进 Si C颗粒与铜共沉积的混合添加剂 ,可获得 Si Cp 含量较高的Cu/ Si Cp复合材料 .

铜基封装材料的研究进展

具有高导热性的铜基封装材料可以满足大功率器件即时快速大量散热的要求,是一种重要的封装材料。综述了Cu/Mo、Cu/W传统铜基封装材料和Cu/C纤维、Cu/Invar(Mo、Kovar)/Cu层状材料、Cu/ZrW2O8(Ti-Ni)负热膨胀材料及Cu/SiC、Cu/Si轻质材料等新型铜基封装材料的性能特点、制备工艺与问题。指出轻质Cu/Si复合材料将是铜基封装材料中一个新的具有前景的研究方向。

SiC_P/Mg复合材料的界面结构

采用真空压力浸渍法制备了碳化硅颗粒增强铸造镁合金（ＺＭ５）复合材料，碳化硅颗粒的平均尺寸为４μｍ，体积分数为４５％。通过透射电镜（ＴＥＭ）、能量色散谱仪（ＥＤＳ）研究了这种复合材料的ＳｉＣＰ／Ｍｇ界面微结构。实验结果表明：碳化硅颗粒与镁基体的界面结合紧密，界面区域存在合金元素铝的偏聚，并形成块状和细针状γ（Ｍｇ１７Ａｌ１２）相，这种γ相提高了界面结合强度。在ＳｉＣＰ／Ｍｇ界面区域存在高密度的位错缠结，这将对复合材料整体强度的提高作出贡献。另外，在有些ＳｉＣＰ／Ｍｇ界面上观察到氧化镁微晶层以及较大的氧化镁颗粒。

SiC微粒填充铸型尼龙复合材料的研究

对ＳｉＣ微粒填充铸型尼龙（ＭＣ尼龙）复合材料进行了研究，试验结果表明：材料制备的工艺流程对其力学性能有明显的影响，使用钛酸酯偶联剂对颗粒进行表面处理比硅烷偶联剂（ＫＨ５５０）更有效．随着填料含量的变化材料的力学性能发生变化，填料质量分数大约在５％时具有最好的综合性能．

碳化硼颗粒增强Cu基复合材料的研究

研究了用表面涂覆含钛金属涂层的碳化硼颗粒增强 Cu基复合材料 [B4Cp/(Ti B2 +Ti N) /Cu],并与未经涂覆的 B4C颗粒增强 Cu基复合材料 (B4Cp/Cu)进行了对比。实验结果表明 ,前者的致密度和电导率比后者好。磨损实验结果表明 ,使用有涂层颗粒的复合材料的耐磨性比无涂层颗粒的好。通过对复合材料界面和磨损表面的电镜观察表明 ,B4C颗粒经过涂覆处理后 ,改善了复合材料的界面粘结性能 。

缺陷控制与ZTM／SiC_p复合陶瓷的强度

采用湿化学法制备超细莫来石和氧化锆粉末，添加微米碳化硅粉料后，再进行充分均匀混合，经压滤成型获得均匀、致密、缺陷小的坯体，研究了不同热压工艺条件对复合陶瓷强度的影响。实验发现适当降低热压温度和延长保温时间有利于强度提高，由于材料的微观结构处于较佳状态，缺陷获得有效控制，多种强化机制有效发挥，材料最大强度达到：室温为８１０ＭＰａ，１０００℃下为５３６ＭＰａ，这比目前国内外文献所报道的莫来石基颗粒复合材料的强度数据有较大突破。此外分析了微米颗粒对超细陶瓷基体强化的机制。

柔性防刺涤纶/碳化硅织物的制备及其防刺性能

针对目前市场上的防刺服价格高、柔韧性差、难以在军民领域得到普及的问题,通过在涤纶机织物上涂覆不同粒径的碳化硅(SiC)颗粒制得了一种柔性防刺复合材料,涂覆方式分为单次涂覆和双次涂覆。通过扫描电子显微镜观察和多层动态穿刺性能测试研究了SiC颗粒大小和涂覆方式对该复合材料防刺性能的影响,并且分析了6层单面双层涂覆方式制备的柔性防刺复合材料的耗散吸能模式。结果表明:采用180 μm SiC颗粒制得的复合材料防刺性能最好;当采用双次涂覆方式时,采用单面双层涂覆方式制得的复合材料防刺性能优于采用双面单层涂覆方式;单面双层涂覆方式制备的复合材料主要有2种能量耗散模式。

电沉积制备铜基复合镀层的研究进展

兼具工艺成本低、工艺流程简单和工艺柔性好等优势的电沉积技术,是制备单元/多元金属基复合镀层的工艺方法。以电沉积制备铜-非金属化合物复合镀层和铜-金属微粒复合镀层为主题,选取制备工艺、参数条件优化及性能表征等方面作为切入点,分别进行概述。

无压浸渗法制备碳化硅颗粒增强铝基复合材料工艺研究

用有预制型的无压浸渗法制备了体积分数高达75%的碳化硅颗粒增强铝基复合材料。研究了各工艺参数对复合材料制备过程与性能的影响。结果表明:SiO2氧化膜、N2气氛和充分的保温时间有利于浸渗;浸渗温度选择1000℃比较合适;M g的质量分数为10%时浸渗能顺利进行。

镍基纳米SiC-Al_2O_3复合电刷镀层的组织及性能

在45#钢基体上制备了n-Al2O3/Ni和n-SiC–Al2O3/Ni复合刷镀层,采用能谱仪(EDS)、X射线衍射仪(XRD)、扫描电镜(SEM)和T-11球盘式磨损试验机等设备对比研究了2种复合刷镀层的组织及性能。EDS分析结果表明,n–Al2O3/Ni复合刷镀层中纳米颗粒特征元素Al的质量分数为5.65%,n-SiC–Al2O3/Ni复合刷镀层中纳米颗粒特征元素Al的质量分数为5.63%,Si元素的质量分数为4.86%。SEM分析结果表明,与n-Al2O3/Ni复合刷镀层相比,n-SiC–Al2O3/Ni复合刷镀层的表面更加平整,组织更加细化。n-SiC–Al2O3/Ni和n-Al2O3/Ni复合刷镀层的显微硬度分别为587HV和555HV,n-SiC–Al2O3/Ni复合刷镀层的耐磨性是n-Al2O3/Ni复合刷镀层的1.7倍。