Corona Generation and Deposition of Metal Nanoparticles on Conductive Surfaces and Their Effects on the Substrate Surface Texture and Chemistry

ABSTRACTThin Me-DLC films with different metal contents have been deposited by ECR-CVD (Electron Cyclotron Resonance Chemical Vapour Deposition). Before the growth process, metal nanoparticles were scattered over the substrate surface by dipping it into a dispersion previously sonicated. The concentration of the dispersion (150, 300, 500 and 5000 ppm) controls the metal content into the carbon coating. The morphology of the deposited samples was analysed by SEM (Scanning Electron Microscopy). The metal content in the carbon films has been evaluated by SIMS (Secondary Ion Mass Spectroscopy). The incorporation of low amounts of metal nanoparticles into the hard carbon coating produces an outstanding improvement in the durability of the layer, as detected by pin-on-disc tests. For an optimum chromium content of 300 ppm of nanoparticles in the dispersion, the grown layer exhibits a noteworthy higher wear resistance respect to that of the DLC reference film. More precisely, in this case, the Cr-DLC coating undergoes ten times longer wear process than the reference DLC coating. However, it is important to indicate that in samples grown using more concentrated dispersions (> 300 ppm), a rapid deterioration of the coating is produced and short lifetimes have been detected, attributed to the large contribution of metal to the transfer layer.

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Charge Transfer to Metal Nanoparticles Bouncing from Conductive Surfaces

Aerosol Science and Technology ◽

10.1080/02786826.2014.955566 ◽

2014 ◽

Vol 48 (10) ◽

pp. 1059-1069 ◽

Cited By ~ 2

Author(s):

S. Rennecke ◽

A. P. Weber

Keyword(s):

Charge Transfer ◽

Metal Nanoparticles ◽

Conductive Surfaces

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Electron microscopy studies of plasma-sprayed materials

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100074276 ◽

1983 ◽

Vol 41 ◽

pp. 70-71

Author(s):

K.R. Subramanian ◽

A.H. King ◽

H. Herman

Keyword(s):

Plasma Spraying ◽

Substrate Surface ◽

Flame Temperature ◽

Ceramic Coatings ◽

Metallic Substrates ◽

Hot Plasma ◽

Almost All ◽

Plasma Sprayed ◽

Hostile Environments ◽

Plasma Spraying Process

Plasma spraying is a technique which is used to apply coatings to metallic substrates for a variety of purposes, including hardfacing, corrosion resistance and thermal barrier applications. Almost all of the applications of this somewhat esoteric fabrication technique involve materials in hostile environments and the integrity of the coatings is of paramount importance: the effects of process variables on such properties as adhesive strength, cohesive strength and hardness of the substrate/coating system, however, are poorly understood.Briefly, the plasma spraying process involves forming a hot plasma jet with a maximum flame temperature of approximately 20,000K and a gas velocity of about 40m/s. Into this jet the coating material is injected, in powder form, so it is heated and projected at the substrate surface. Relatively thick metallic or ceramic coatings may be speedily built up using this technique.

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Feasibility of Molecular Structure Determination With a High Resolution Electron Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100101438 ◽

1968 ◽

Vol 26 ◽

pp. 338-339

Author(s):

T. A. Welton

Keyword(s):

Electron Microscope ◽

Substrate Surface ◽

Helical Axis ◽

Base Plane ◽

Resolution Electron ◽

High Resolution Electron Microscope ◽

High Degree ◽

Degree Of Order ◽

Purine Pyrimidine

An ultimate design goal for an improved electron microscope, aimed at biological applications, is the determination of the structure of complex bio-molecules. As a prototype of this class of problems, we propose to examine the possibility of reading DNA sequence by an imaginable instrument design. This problem ideally combines absolute importance and relative simplicity, in as much as the problem of enzyme structure seems to be a much more difficult one.The proposed technique involves the deposition on a thin graphite lamina of intact double helical DNA rods. If the structure can be maintained under vacuum conditions, we can then make use of the high degree of order to greatly reduce the work involved in discriminating between the four possible purine-pyrimidine arrangements in each base plane. The phosphorus atoms of the back bone form in projection (the helical axis being necessarily parallel to the substrate surface) two intertwined sinusoids. If these phosphorus atoms have been located up to a certain point on the molecule, we have available excellent information on the orientation of the base plane at that point, and can then locate in projection the key atoms for discrimination of the four alternatives.

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Morphologies of Nonadherent Al2O3 and Matching Substrate Surfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010009587x ◽

1972 ◽

Vol 30 ◽

pp. 524-525

Author(s):

C. S. Giggins ◽

J. K. Tien ◽

B. H. Kear ◽

F. S. Pettit

Keyword(s):

Electron Microscopy ◽

Oxide Scale ◽

Oxidation Resistance ◽

Substrate Surface ◽

Morphological Features ◽

Thermally Induced ◽

Oxide Spallation ◽

Oxidation Resistant ◽

Induced Stresses ◽

Substrate Surfaces

The performance of most oxidation resistant alloys and coatings is markedly improved if the oxide scale strongly adheres to the substrate surface. Consequently, in order to develop alloys and coatings with improved oxidation resistance, it has become necessary to determine the conditions that lead to spallation of oxides from the surfaces of alloys. In what follows, the morphological features of nonadherent Al2O3, and the substrate surfaces from which the Al2O3 has spalled, are presented and related to oxide spallation.The Al2O3, scales were developed by oxidizing Fe-25Cr-4Al (w/o) and Ni-rich Ni3 (Al,Ta) alloys in air at 1200°C. These scales spalled from their substrates upon cooling as a result of thermally induced stresses. The scales and the alloy substrate surfaces were then examined by scanning and replication electron microscopy.The Al2O3, scales from the Fe-Cr-Al contained filamentary protrusions at the oxide-gas interface, Fig. 1(a). In addition, nodules of oxide have been developed such that cavities were formed between the oxide and the substrate, Fig. 1(a).

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