超细WC-10%Co复合粉体的激光熔覆工艺特性

为了研究化学镀法制备的WC-10%Co复合粉体的激光熔覆工艺特性,用体视显微镜和扫描电镜对采用不同激光熔覆工艺参数熔覆复合粉体制备的涂层表面形貌进行观察,探讨了激光熔覆工艺参数对熔覆层与基体结合状况的影响,分析了采用优化工艺制备的复合熔覆层的耐磨性能及其截面组织形貌.研究发现,当激光功率为2.0～2.4 kW、扫描速率为4.1 m/min、光斑直径为3 mm时,制备的WC-10%Co熔覆层与基体形成冶金结合,基体耐磨性能大大改善.     

Preparation and Properties of W-15Cu Composite by Electroless Plating and Powder Metallurgy

用化学镀和粉末冶金的方法制备出W-15Cu复合材料。首先用化学方法对W粉表面预处理,然后在其表面化学镀铜。得到的复合粉末用图谱进行表征。发现用化学镀的方法制备出的W-15Cu复合粉末纯度非常高,且W颗粒均匀、被Cu致密的包覆着。呈现出包状结构。这种复合粉末表现出优异的压制性能,压坯分别在300, 400, 500, 600 MPa的压制压力下成形。压坯在1250 ℃温度下保温90 min烧结后,从其断口形貌可以发现W颗粒没有明显的长大,且W颗粒表面特征并没有发生改变,仍然表现出预处理后的表面特征。对烧结体的相对密度、硬度、抗弯强度和电导率同样进行了表征     

Assessing Small Hole Plating Capabilities

A series of Hadamard designed experiments were used to evaluate the high aspect ratio plating capabilities and opportunities for extending that capability at the Tektronix Forest Grove Circuit Board Manufacturing Division. The investigation employed IPC-A-39 artwork to explore the effects of various factors in the electroless copper, electrolytic copper, and tin plating processes on electrical opens in small holes. Failed through holes were also examined using standard metallurgical techniques. The results showed: 1) The tin etch resist was the primary source of failures within the Tektronix plating process.

2) Higher current density in the bright acid tin process and replacing bright acid tin with matte tin significantly reduced the number of failures.

3) None of the factors tested for the electroless copper process had any impact on the number of failures.

     

化学镀模板法制备纳米镍金属管

主要研究了以纳米碳纤维为模板,利用化学镀工艺制备镍纳米管的方法.该方法包括模板的预处理、化学镀、去模板以及对终产物的还原处理.利用场发射扫描电子显微镜(SEM)观察不同阶段的产物表面形貌,利用透射电子显微镜(TEM)观察终产物形貌,利用粉末-X射线衍射(XRD)对终产物成分进行表征.结果表明,利用纳米碳纤维为模板通过化学镀的方法可以获得镍纳米管.     

工业缝纫机梭床耐磨性研究

分析了缝纫机梭床磨损失效原因。论述了Ni-P化学镀表面技术应用于缝纫机梭床上的可行性。借助扫描电镜、能谱仪、磨损试验机、显微硬度计等设备对化学镀层的表面状态、组织结构及性能进行综合分析。结果表明，Ni-P化学镀层的硬度、耐磨性远远高于碳氮共渗层。其中Ni-P-SiC化学复合镀层的性能最好。同时对化学镀层的高硬度、高耐磨性进行了分析说明。     

Cu@Ag包覆粉体的SPS烧结及其致密机理研究

采用化学镀法制备Cu@Ag包覆粉体,并利用放电等离子烧结技术(SPS)对其进行烧结,利用扫描电子显微镜、透射电子显微镜研究包覆粉体、烧结样品的微观结构,对烧结样品的物相、致密度及其致密化机理进行表征与分析。结果表明,化学镀法制备的Cu@Ag粉体表面存在高纯的包覆层。在较低的烧结温度下可以得到致密度高的Cu-Ag烧结块体,温度升高,Cu-Ag烧结块体的致密度逐渐升高,550℃时,致密度达到极大值96.76%。分析认为,得益于Cu@Ag粉体的包覆结构,在低温下,铜颗粒表面的纳米银的颈缩促进了烧结;在高温下,Cu、Ag间的固溶进一步促进了烧结。     

Preparation of flake AgSnO2 composite powders by hydrothermal method

Silver-tin oxide composite powders and silver powders were synthesized by hydrothermal method using NHs to complex Ag^＋, SO3^2- to reduce Ag（NH3）2^＋ and Na2SnO3 as the source of tin. The powders were characterized by XRD, SEM and EDX. The results show that there are macroscopic and microscopic differences between two kinds of powders. Spherical silver powders are 3μm in diameter, and silver-tin oxide composite powders are mainly flake of about 0.3μm in thickness. Silver crystal in silver-tin oxide composite powders is preferentially oriented in the （111） crystallographic direction and its oriented index is 2.581. Crystal lattice parameter of silver crystal of silver tin-oxide composite powders is 0.409 34 nm, larger than 0.408 68 nm of silver powders. The XPS analysis shows that silver in silver-tin oxide composite powders is metallic silver and tin oxide in silver tin-oxide composite powders has the red shift for Sn^4＋（3d（5/2）） and O^2-（1s）.     

化学镀对掺杂态聚苯胺粉体电磁性能影响分析与表征

用NiSO4·6H2O和CoSO4·7H2O为主盐、NaH2PO2·H2O为还原剂,在高氯酸掺杂聚苯胺( HClO4-PANI)粉体表面化学镀覆Ni-Co-P合金镀层,用扫描电镜分析粉体形貌,利用同轴网络传输反射法,测定了镀覆后聚苯胺粉体的电磁参数,分析了化学镀对其电磁性能的影响,以期制备出以导电聚苯胺为基体的复合轻质...     

Synthesis and microwave characterization of Co-SiC core-shell powders by electroless plating

Co-SiC core-shell powders were prepared by electroless plating. Scanning electron microscopy （SEM） revealed that Co-SiC core-shell powders were of nearly sphere-like shape and were about 0.3 pan. X-ray powder diffraction （XRD） patterns showed that the cobalt powder was hexagonal crystallite. The complex dielectric constant and the complex permeability of Co-SiC core-shell powders-paraffin wax composite were measured by the rectangle wavegnide method. It showed that the dielectric loss was less than 0.1 and the magnetic loss was about 0.2 in 8.2-12.4 GHz for prepared Co-SiC core-shell comoosite oowders.     

化学镀的研究进展及发展趋势

化学镀能够有效增强基体材料的表面性能,拓展其应用范围,在许多领域具有广泛的应用前景。综述了化学镀的基本原理、处理方法及施镀工艺,详细讨论了化学镀的研究进展。归纳了化学镀层的种类及应用技术,主要包括化学镀镍、化学镀铜、化学镀钴、化学镀银、化学镀锡、化学镀金等。分别讨论了各类化学镀的研究进展、优势、劣势及应用范围。在此基础上归纳了化学镀存在的问题,主要为对能源的消耗和对环境的污染,引起了人们的广泛关注。化学镀技术发展呈现多元化的趋势,主要集中在激光增强化学镀、超声波化学镀、粉体化学镀、多层化学镀、稀土化学镀、复合化学镀。化学镀未来的发展方向一是原有化学镀工艺的进一步完善和提高,二是具有商业价值的新领域以及超功能性新材料所带来的化学镀技术新应用。     

稀土永磁材料表面超声波化学镀层性能研究

为了提高稀土永磁材料表面的防腐蚀性能,通过化学镀的方式对稀土永磁材料进行表面处理.根据稀土永磁材料表面疏松多孔的特性,将超声波技术引入到化学镀工艺中,利用孔隙率测试、扫描电子显微镜、热震试验、电化学测试、盐雾试验及湿热试验等检测手段,对镀层的孔隙率、形貌、结合力以及镀层的耐腐蚀性能进行了分析,并将超声波化学镀层与常规化学镀层的性能进行了比较.研究结果表明:超声波技术的应用能有效地降低化学镀层的孔隙率,提高镀层的结合力和耐腐蚀性能.     

不同形状钨粉化学镀铜的研究

通过化学镀法制备铜包钨复合粉末,研究不规则形状的钨粉以及经等离子球化处理的球形钨粉的化学镀铜。结果表明,对于颗粒形貌不规则棱角分明的破碎钨粉,经化学镀包覆后粉末没有明显的棱角,表面粗糙。而经等离子球化处理后球形度较高的球形粉,颗粒表面存在缺陷,化学镀后粉末的球形度没有明显的变化,化学镀层在其表面沉积均匀,且钨粉表面质量得到改善,不存在表面缺陷。化学镀后复合粉末在600℃下进行氢气退火处理后,镀层上的粗糙的表面变得平滑,镀层中的空隙明显减少,形成了一层均匀致密的铜层包覆在钨颗粒表面。     

Synthesis and characterization of Ni–P coated hexagonal boron nitride by electroless nickel deposition

Electroless plating has been receiving a steady progress over the last decade on the modification of the surface properties of ceramic materials in order to produce composite coatings with unique characteristics for critical tribological systems. In this work, an electroless nickel deposition process was used to deposit nickel-phosphorous (Ni–P) coating on hexagonal boron nitride (h-BN) particles via hypophosphitereduced acid bath solution. The substrate particles were initially subjected to series of pre-treatment operation in order to ensure that the particles are cleaned and catalytically active prior to electroless plating. The characterization of the as-received and Ni-coated powder was studied through scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy and field emission scanning electron microscopy (FESEM). The result reveals that the pretreatment of h-BN powder provides substrate particle surfaces with coarse and roughened structures which are normally considered suitable for Ni–P deposition. Moreover, the result of the EDX analysis confirms the existence of nucleating agents and Ni–P coating on the surface of the treated h-BN powder. The cross-sectional microstructure of the coated powder shows that the h-BN particles were embedded in a continuous matrix layer of Ni–P deposit. The EDX mapping profiles further indicate that the deposited Ni–P alloy mass was uniformly distributed on the surface of the Ni–P codeposited h-BN particles (Ni–P–h-BN). The successful development of Ni coated h-BN powder will raise the potential of h-BN as a high-performance coating material.     

Preparation of nickel-coated tungsten carbide powders by room temperature ultrasonic-assisted electroless plating

In this paper nickel (Ni)-coated tungsten carbide (WC) composite powders have been synthesized by ultrasonic-assisted electroless plating with a simplified pretreatment at room temperature as the conventional sensitization and activation steps have not been employed. The growth mechanism of Ni layers and surface morphologies and composition of initial WC powders, pretreated WC powders and Ni-coated WC powders were analyzed by field emission scanning electron microscopy, and energy dispersion spectrometry. The results shows that uniform Ni-coated WC composite powders were successfully synthesized without conventional sensitization and activation steps by ultrasonic-assisted electroless plating at room temperature. The growth mechanism of Ni layers appears as follows: the surfaces of pretreated WC powders appear step-like defects which act as activated sites. Nucleation and the growth of nickel grains take place on the activated sites of pretreated WC powder, and the process repeats continuously on the lath particles with reticulate structure on the as-coated surfaces of previously deposited Ni-cells, finally Ni cells grow up and merge into a layer.     

化学沉积 Ni-P-荧光粉复合镀层及其性能研究

目的以铜合金为基体,采用化学镀技术制备Ni-P-荧光粉复合镀层。方法在化学镀镍液中加入荧光粉微粒,在不同条件下施镀,并对不同工艺参数下获得的镀层的表面形貌、结构和荧光特性进行研究。结果化学沉积Ni-P-荧光粉复合镀层的沉积方式为颗粒堆积,镀液中荧光粉的浓度和镀液的pH值对镀层中荧光粉的含量有影响。荧光粉微粒的加入使得镀层表面色泽变暗,外观较粗糙。对复合镀层进行荧光分析发现,激发光谱在激发波长450~560 nm范围内存在荧光峰,发射光谱在发射波长420~500 nm范围内存在荧光峰。结论采用合理的工艺参数可以获得Ni-P-荧光粉复合镀层,且镀液pH=5.0时,荧光效果最佳。     

反应合成银氧化锡电接触材料导电性能研究

采用反应合成技术和传统粉末冶金技术制备银氧化锡(AgSnO2)电接触材料。对AgSnO2块体材料进行导电率测试和X射线衍射分析，对块体材料及冷拉拔的AgSnO2线材进行显微组织分析(扫描电镜、透射电镜)。研究结果表明：采用反应合成技术可以在银基体中合成尺寸细小、界面新鲜的SnO2颗粒，制备AgSnO2电接触材料；反应合成法制备的AgSnO2材料中，微米级的SnO2颗粒系由纳米级的SnO2颗粒聚集而成；反应合成法制备的AgSnO2电接触材料较传统粉末冶金法制备的AgSnO2电接触材料具有更高的导电性；采用反应合成法制备的AgSnO2电接触材料由于改变了Ag和SnO2的结合状态使材料的加工性能和导电性能同时得到改善和提高。     

表面活性剂对镍-磷-纳米氧化铝复合镀的影响

研究了阴离子型表面活性剂(十二烷基苯磺酸钠、十二烷基硫酸钠)和阳离子型表面活性剂(三乙醇胺)对镍-磷-纳米氧化铝复合镀性能的影响.讨论了表面活性剂的种类、加入量对沉积速度、镀层的硬度和耐磨性能的影响.通过扫描电镜(SEM)观察各种复合镀层形貌,利用能谱仪(EDS)测量镀层中纳米A l2O3粒子的复合量.结果表明:纳米复合化学镀液中两种阴离子型表面活性剂的较佳加入量均为50 mg/L,阳离子型表面活性剂较佳加入量为100mg/L;采用阳离子表面活性剂时所得镀层的纳米粒子复合量较大,镀速快,耐磨性能好且纳米氧化铝分散较均匀;相比化学镀N i-P和微米A l2O3复合化学镀N i-P工艺所得镀层,纳米复合镀层具有较高的硬度和较好的耐磨性.     

Ti3SiC2陶瓷颗粒表面超声波化学镀铜

钛碳化硅（Ti3SiC2）陶瓷导电材料有许多优异的性能，其摩擦系数甚至比石墨更低，完全可以取代石墨用来制备性能更加优良的铜基电接触复合材料，但是由于其与铜基体之间的浸润性不是很好，研究了利用超声波化学镀覆技术在Ti3SiC2颗粒表面均匀镀上一层连续的铜镀层。通过扫描电子显微镜对铜镀层表面形貌的观察表明：通过严格的镀前预处理工艺的优化设计以增加活化点，对传统镀液配方的调整以降低镀速，能够成功的在Ti3SiC2颗粒表面均匀镀覆一层铜微粒，改善了Ti3SiC2和铜基体间的润湿性，从而增强二者之间的界面结合力。     

氧化铝陶瓷基板化学镀铜工艺优化

目的化学镀铜是氧化铝陶瓷基板金属化的一种重要手段,为了进一步优化氧化铝陶瓷基板化学镀铜工艺,研究了化学镀铜液配比(尤其是镀液中铜离子和甲醛含量)对氧化铝陶瓷覆铜板微结构和导电性的影响。方法在对氧化铝陶瓷基板经过前期处理后,采用化学镀铜法在基板上镀铜。采用X射线衍射仪、光学显微镜对氧化铝基板上的化学镀铜层物相和形貌进行观察。采用覆层测厚仪、四探针测试仪对化学铜镀层的膜厚和方阻进行测量。结果 XRD结果表明,不同配比镀液得到的化学镀铜层均具有较好的晶化程度,镀液中甲醛和铜含量较低的镀液可制备出晶粒更为细小的化学镀铜层。甲醛和铜离子含量均较高时,沉积速度过快,使镀铜层的均匀性和致密性不佳。但当甲醛含量较高、铜离子含量较低时,沉积速度适中,从而获得了均匀性和致密性较好的镀铜层,同时这种镀层具有良好的导电性。结论采用表面活性化学镀铜工艺,当镀液中甲醛浓度为0.25 mol/L和硫酸铜质量浓度为1.2 g/L时,无需高温热处理,即获得了均匀性和致密性俱佳的铜镀层,可满足覆铜板的使用要求。     

Electroless nickel deposition on silane modified bamboo fabric through silver,copper or nickel activation

Palladium-free process for the electroless nickel deposition on bamboo fabric (BF) has been developed. The process is based on 3-aminopropyltrimethoxysilane (APTMS) chemically grafted onto BF via a simple etchless method. Hence, Ni/BF composites can be obtained in three steps, namely: (i) the grafting of APTMS onto BF, (ii) the silver (Ag⁰), copper (Cu⁰) or nickel (Ni⁰) activating of the BF surface, and (iii) the nickel metallization using electroless plating bath. IR, XPS, XRD and SEM were used to characterize each step of the process. The nickel coating through silver activation has a smoother surface, higher electrical conductivity and better electromagnetic interference shielding effectiveness (EMI SE) by comparing to the other two activation samples. Magnetic property of the Ni/BF composites was measured, and composite from Ni activation has a larger saturation magnetization than the two left composites. All the nickel coatings via different metal activations are adhered firmly to the BF substrates, as determined by a standard adhesive Scotch®-tape test.