盐浴法金刚石表面镀铬研究

在盐浴条件下,研究了金刚石表面镀铬工艺,用XRD和SEM研究了表面镀Cr金刚石的相结构和表面形貌,测定了镀铬后金刚石的强度。结果表明镀铬后金刚石表面形成良好的碳化物镀层,且金刚石强度提高。初步探讨了金刚石表面碳化物镀层提高金刚石及其工具性能的原因。     

Fabrication and characterization of copper-diamond particles

The electroless copper deposition on both pure and Cr-coated diamond particles was studied to produce copper/diamond composites for electronic packaging materials. The particles were characterized and the mechanism of product formation was investigated through scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectra (XPS). The particle coating thickness was measured using optical micrographs. The diamond particles got uniform coating thickness of copper crystals layers. This method provided an excellent base for the fabrication of metal-based composites using cheap equipments, and was less time consuming, nature friendly and economical compared with other methods of diamond surface metallization.     

STUDY ON SURFACE OF DIAMOND PARTICLE BY CHEMICAL CU-CLADDING AND ITS APPLICATION IN DIAMOND WHEEL

In this paper,a method that a layer of Cuwas cladded on the surface of diamond particle by an apprro-priate chemically Cu-cladded process was put forward.Themethod can adjust the thickness of cladding by one step ormultiple steps.The composition and structure of Cu-claddeddiamond were analyzed with help of XRD,SEM and EP-MA.The results show that copper was homogeneously dis-persed on the surface of diamond particle by this method,thedeposited copper is loosely dispersed by one step cladding pro-cess,and the copper is tightly organized by multiple stepscladding process.Copper presents crystalline,and a smallamount of oxygen and iron exits in copper layer.Wearing testshows that the wear-resisting property of Cu-cladded dia-mond wheel is superior to that of general diamona wheel,andthat of diamond of which Cu-cladded thickness is depositedmore thickly by multi-steps cladding process is better.     

Preparation and properties of the Ni-Al/Fe-Al intermetallics composite coating produced by plasma cladding

A novel approach to produce an intermetallic composite coating was put forward.The microstructure,microhardness,and dry-sliding wear behavior of the composite coating were investigated using X-ray diffraction (XRD),scanning electron microscopy (SEM),energy dispersive spectrum (EDS) analysis,microhardness test,and ball-on-disc wear experiment.XRD results indicate that some new phases FeAl,Fe0.23Ni0.77Al,and Ni3Al exit in the composite coating with the Al2O3 addition.SEM results show that the coating is bonde...     

大面积金刚石膜生长过程中的缺陷和内应力

采用甲烷和氢气作为气源,在直径为50 mm的抛光单晶硅片上,利用新型微波等离子体化学气相沉积(MPCVD)装置制备出金刚石膜.用扫描电子显微镜观测金刚石膜的表面形貌,利用激光Raman光谱表征金刚石膜的质量以及X射线衍射检测金刚石膜的成分和晶界缺陷.结果表明V(CH4)/V(H2)为1%,基片温度为845℃时,生长金刚石膜的质量较好,并且具有完整的晶体形貌,但是扫描电子显微镜图×5 000倍时,观察到金刚石膜中明显的晶体缺陷存在,同时X射线衍射图表明金刚石膜的内应力较大.     

Dry wear behaviors of wear resistant composite coatings produced by laser cladding

Using different proportional mixtures of Ni-coated MoS2, TiC and pure Ni powders, new typical wear resistant and selflubricant coatings were formed on low carbon steel by laser cladding process. The microstructures and phase composition of the composite coatings were studied by SEM and XRD. The typical microstructure of the composite coating is composed of multisulfide phases including binary element sulfide and ternary element sulfide, γ-Ni, TiC and Mo2C. Wear tests were carried out using an FALEX-6 type pin-on-disc machine. The friction coefficient and mass loss of three kinds of MoS2/TiC/Ni laser clad coatings are lower than those of quenched 45 steel, and the worn surfaces of the laser cladding coatings are very smooth. Because of high hardness combined with low friction, the laser cladding composite coating with a mixture of 70% Ni-coated MoS2, 20%TiC and 10% pure Ni powder presents better wear behaviors than the composite coating with other powder blends. The composition analysis of the worn surface of GCr15 bearing steel shows that the transferred film from the laser cladding coating to the opposite surface of GCr15 bearing steel contains an amount of sulfide, which can change the micro-friction mechanism and lead to a reduced friction coefficient.     

Behavior of NiCrAIY coating on the TC6 titanium alloy

A NiCrAlY coating was deposited on the TC6 titanium substrate by arc ion plating (AIP). The structure and morphologies of the NiCrAlY coating were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the influence of vacuum heat treatment on the element diffusion behavior was studied. The results showed that the γ'-Ni3Al phase was precipitated on the NiCrAlY coating after heat treatment. The Ni3(Al,Ti), TiNi, and Ti2Ni intermetallic layers appeared at the interface from the outside to the inside at 700°C, and the thickness of the intermetallic layers increased with the increase in temperature. At 700°C Ti and Ni were the major diffusion elements, and the diffusion of Cr was observed when the heat treatment temperature increased up to 870°C. The violent inward diffusion of Ni at 950°C resulted in the degradation of the NiCrAlY coating.     

Properties of plasma sprayed NiCrAlY (ZrO_2 Y_2O_3) coating on refractory steel surface

1INTRODUCTION1Cr18Ni9Ti,i.e.188austeniticstainless steel,isakindofausteniticrefractorysteelwidely appliedinmanyfields,containingahighcontentofCrthatcanimproveheatandoxidationresistances,andalsoNicapableofformingastableaustenitic structure.However,suchstee…     

Laser cladding of Ni-based alloy on copper substrate

The laser cladding of Ni1015 alloy on Cu substrate was prepared by a high power continuous wave CO2 laser. Its microstructure was analyzed by optical microscope （OM）, scanning electron microscope （SEM）, and X-Ray diffraction （XRD）. The average microhardness of the cladding coating was Hv 280, which was almost three times of that of the Cu substrate （Hv 85）. OM and SEM observations showed that the obtained coating had a smooth and uniform surface, as well as a metallurgical combination with the Cu substrate without cracks and pores at the interface. With the addition of copper into the nickel-based alloy, the differences of thermal expansion coefficient and melting point between the interlayer and cladding were reduced, which resulted in low stresses during rapid cooling. Moreover, large amount of （Cu, Ni） solid solution formed a metallurgical bonding between the cladding coating and the substrate, which also relaxed the stresses, leading to the reduction of interfacial cracks and pores after laser cladding.     

常压微波等离子射流脱碳处理有机工业废气

在自行设计的常压微波等离子体射流装置上进行了丙酮模拟有机工业废气的脱碳实验,得到了纳米碳粉。利用Raman光谱、XRD、SEM、TEM和EDAX对制得的碳粉的结构和形貌进行了分析。体积分数62.5％的有机废气在等离子体射流的作用下得到的固态碳粉以微晶石墨结构为主,含有少量的微晶金刚石结构．TEM分析表明石墨晶体为颗粒状和层状结构．该技术可用于有机废气的脱碳处理和纳米碳粉的回收利用。     

等离子喷涂参数对镍基合金涂层组织及冲蚀磨损性能的影响

采用SEM、XRD、LSCM和冲蚀磨损试验机研究了等离子喷涂参数(氢气流量HFR、喷涂电流I)对Ni60涂层组织与冲蚀磨损性能的影响。结果表明,Ni60涂层主要由γ-Ni、Ni3B、Cr2B、CrB、M7C3、M23C6相构成;增加HFR、I有利于减小涂层中层片厚度,增加涂层结晶度、平均晶粒尺寸、微观应变量及残余应力,提高涂层显微硬度及抗冲蚀磨损性能。但过大的HFR、I(15ft3/h、600A)导致涂层孔隙率增加,显微硬度及抗冲蚀磨损性能降低。等离子喷涂参数HFR=12.5ft3/h、I=500A时,在小角度冲蚀条件下,Ni60涂层具有更高的抗冲蚀磨损性能。     

自蔓延高温合成软磁Ni-Zn铁氧体的研究

采用自蔓延高温合成法合成了 Ni0 .4 Zn0 .6 Fe2 O4 ,研究了反应温度、燃烧波速率与放热系数 k值之间的关系。并通过 XRD、SEM、VSM等测试手段对产物的形貌、物相、结构及性能进行了分析 ,结果表明当放热系数 k=0 .6时 ,反应比较完全 ,合成产物颗粒大小均匀 ,产物具有较高的比饱和磁化强度和低的矫顽力     

镀铜金刚石树脂砂轮的研究

通过选择合适的化学镀铜工艺在金刚石表面镀覆一层金属铜，该方法可以调节镀层厚度，可一次镀也可多次镀。通过ＸＲＤ、ＳＥＭ、ＥＰＭＡ等分析手段对镀铜金刚石进行了分析，结果表明：一次镀镀层形貌松散，多次镀镀层形貌紧密，镀层铜呈晶态，并含有少量的氧和铁等杂质。磨削结果表明：镀铜金刚石砂轮其耐磨性明显优于普通金刚石砂轮，多次镀铜铜含量较高的金刚石更适合于制造树脂砂轮     

熔融Zn液对金属Ni腐蚀机理的影响

为了研究金属Ni在熔融锌液中的失效机理,将纯Ni金属和利用等离子喷涂技术制备的Ni涂层试件分别在530℃锌液中浸蚀不同时间,并制备得到金相试样.利用扫描电子显微镜和能谱仪观察腐蚀层的组织形貌和相成分变化,利用X射线衍射仪检测了腐蚀层中的生成相.结果表明,通过反应扩散Ni与Zn在腐蚀层以层状形式生成了不同化合物,从而逐渐消耗金属并将最终导致其失效.此外,纯Ni金属在锌液中的腐蚀速率为0.006 04 g/(cm2·h).     

Fe41Co7Cr15Mo14C15B6Y2合金涂层的激光制备及显微组织研究

利用激光熔覆和激光重熔的方法在低碳钢表面制备了原位生成颗粒增强铁基涂层.用X线衍射(XRD)、扫描电镜(SEM)对其相结构和微观组织进行了研究,重点分析了重熔层的组织形态和形成机制.结果表明:制备的涂层无气孔和裂纹,整个涂层的厚度为0.6~0.7 mm,重熔层厚度为50~80 μm;熔覆层主要是方向比较紊乱的树枝晶组织,重熔层内形成了细小的等轴晶组织;重熔层最高显微硬度达到了1056 HV.     

电镀法制备Ni-W合金镀层的耐盐雾腐蚀性能

利用电镀法在N80钢表面制备了Ni-W合金镀层,用SEM、EDS分析了镀层表面与界面形貌以及化学元素的分布,通过XRD测试了镀层物相的组成。在5% NaCl溶液中测试了镀层盐雾腐蚀能力,分析了Ni-W镀层抗盐雾腐蚀机理。试验结果表明,镀层厚度约40m,主相为Ni-W,Ni和W以金属形式存在于镀层中;经过高温热处理后,镀层与基体发生了化学元素扩散现象,形成冶金结合;盐雾腐蚀后镀层表面腐蚀物为Fe的氧化物和氯化物,基体无腐蚀现象发生。     

镍基纳米碳管/二氧化钛复合镀层的制备及性能

为了改善金属基材的表面性能,以钛铁矿为原料,利用微波等离子体化学气相沉积法制备了纳米碳管/二氧化钛复合粉体.采用复合电泳电沉积法在不锈钢基体表面制备了镍基纳米碳管/二氧化钛复合镀层;利用扫描电镜、X射线衍射仪、数显维氏硬度计和电化学测试等手段研究了纳米碳管/二氧化钛复合粉体对复合镀层结构和性能的影响.结果表明纳米碳管/二氧化钛复合粉体的加入有效地减小了复合镀层中镍的晶粒尺寸,促进了金属镍沿(111)晶面择优取向生长,改变了镍的电沉积层结构,提高了镀层的硬度,改善了镀层的耐腐蚀性能;在复合粉体的作用下,复合镀层的硬度与纯镍镀层相比提高了110%,腐蚀电位正移了23mV,腐蚀电流密度减少了0.991微安/平方厘米.     

Properties of plasma sprayed NiCrAlY+(ZrO2+Y2O3) coating on refractory steel surface

NiCrAlY+(ZrO₂+Y₂O₃) thermal barrier coating was prepared on the surface of refractory steel 1Cr18Ni9Ti with plasma spraying technique. The phases and microstructure of the thermal barrier coating were determined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the bonding between thermal barrier coating and substrate is sound. The surface hardness of 1Cr18Ni9Ti reaches up to 1 000 HV, but that of substrate is only 300 HV. The patterns sprayed with CoNiCrAlY+(ZrO₂+Y₂O₃) ceramic coating have a good heat insulation effect at 800 °C for heat insulation temperature difference reaches 54 °C, which increases the operating temperature and service life of refractory steel. Foundation item: Project (5040202140) supported by Scientific Research Common Program of Beijing Municipal Commission of Education     

金刚石表面化学镀Ni-P的研究

对金刚石表面化学镀Ni-P工艺进行了研究，用X射线衍射仪进行了物相鉴定，结果表明：高P化学Ni-P镀层为非晶态，热处理后镀层转变为Ni3P晶态结构．同时证明：Ni-P镀层与金刚石没有发生界面反应．扫描电镜分析表明：Ni-P镀层与金刚石之间的结合状态良好；研究对镀液成分控制和施镀工艺进行了分析．     

超音速火焰喷涂WC-10Co4Cr 涂层组织及耐磨耐蚀性研究

采用超音速火焰喷涂工艺在不同喷涂距离下制备了WC-10Co4Cr涂层,并对其组织结构及耐磨耐腐蚀性能进行了研究。利用金相显微镜、扫描电子显微镜、X射线衍射仪分析了涂层的组织结构和相组成,并测试了涂层显微硬度、孔隙率;对涂层磨损表面进行了观察分析,探讨了涂层的失效形式。结果表明,喷涂距离对涂层的组织结构及耐磨性具有一定影响。适当增加喷涂距离,粒子由于在焰流中停留时间增加而使熔化程度加大,撞击基体后扁平化现象明显。因此,涂层的致密度、耐磨性、耐腐蚀性都有所提高。当喷涂距离为380mm 时,涂层呈现出较好的耐磨性及耐腐蚀性。