DOCSLIB.ORG

(2-8-0 ?Ea-01-Ke 3,574,658 United States Patent Office Patented Apr

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
(2-8-0 ?Ea-01-Ke 3,574,658 United States Patent Office Patented Apr April 13, 1971 M. M. FULK ETAL 3,574,658 DRY-LUBRICATED SURFACE AND METHOD OF PRODUCING SUCH SURFACES Filed Dec. 22, 1967 INVENTOR. MARION M. FULK By JOHN E. SCHRODT (2-8-0 ?ea-01-ke 3,574,658 United States Patent Office Patented Apr. 13, 1971 2 In general, the binder-secured dry lubricant is a step 3,574,658 DRY.LUBRICATED SURFACE AND METHOD OF in the right direction, but is a complicated treatment with PRODUCING SUCH SURFACES many shortcomings. Marion M. Fulk, Livermore, Calif., and John E. Schrodt, It is an object of the instant invention to provide dry Boulder, Colo., assignors to Bal Brothers Research lubricated bearing surfaces which are operable over very Corporation, Boulder, Colo. broad temperature ranges. Filed Dec. 22, 1967, Ser. No. 694,028 Another object of the instant invention is to provide int. CI. B05b 17/00, B24c I/10 a process by which dry lubricants may be applied in a U.S. C. 117-8 16 Claims superior manner to standard size, off-the-shelf parts. O Still another object of the instant invention is to pro vide a process for applying dry lubricants to surfaces of ABSTRACT OF THE DISCLOSURE virtually all configurations or geometry. Dry lubricant such as molybdenum disulfide is applied Yet still another object of the instant invention is to to a solid surface by interposing the lubricant between the provide a dry-lubricated surface having a low coefficient surface and a force generating means such as a peening 15 of friction and rate of wear which is not subject to particle particle, preferably by applying the lubricant initially to flaking. the particle, and then fusing the lubricant to the surface by Still yet another object of the instant invention is to bringing the force to bear upon the surface, and peened provide a dry-lubricated surface having an extremely low surfaces having dry lubricant impacted or fused thereon. vapor pressure in order that the lubricating qualities may 20 be maintained in a vacuum. Yet another object of the instant invention is to pro The instant invention relates to a method of applying vide a method by which dry lubricants may be easily and dry lubricants to surfaces and to surfaces so treated. More readily applied with consistent superior results. specifically, this invention relates to a method of applying A further object of the instant invention is to provide a a dry lubricant by interposing the lubricant between the 25 means of preventing direct metal-to-metal contact between surface and a peening particle and to surfaces having a moving parts. dry lubricant impacted or fused thereon by a peening Another object of the instant invention is to provide a proceSS. method by which dry lubricants may be applied to poly Dry lubricants have been known for some time. How mers and soft metals which degrade at relatively low tem ever, until recently, such lubricants were of the type 30 peratures. represented by graphite and useful only in applications in Other objects and advantages of the instant invention which low lubricating quality and tenacity were required. will be apparent from the following discussion and draw With the relatively recent recognition of the outstanding IngS. lubrication qualities of molybdenum disulfide type lubri According to the instant invention, dry lubricants are cants, the possibility of treating surfaces with a dry 35 applied to Surfaces by impacting them thereon to cause lubricant to obviate the need for running in a liquid lubri the lubricant to fuse to the surface. A rather troublesome cant has been recognized. Unfortunately, this possibility and less desirable method of accomplishing this is by has not yet been achieved although dry lubrication has burnishing or rubbing a dry lubricant into the surface. been achieved to a limited extent. However, this is clearly a time-consuming and cumber One of the first applications of molybdenum disulfide 40 Some process. Though worthwhile results have been ac type dry lubricants was as a dispersion in ordinary oil complished with the burnishing approach, the results are baths, such as an automobile crank case or transmission. markedly inferior to those accomplished by the preferred While such machinery has proven to be more resistant to embodiment of the instant invention. wear when the oil was drained for dry-bearing testing pur Preferably, the dry lubricant is impacted upon the sur poses relative to a similar test with machinery lubricated 45 face by interposing it between the surface and a peening only by the oil per se, there has been substantial evi particle. A peening particle, of course, travels at high dence that the free dispersion of dry lubricant also tends speeds and impacts with very high localized pressures upon to act as an abrasive. This is probably due to the fact the surface. This has been found to securely adhere and that the particles do not all become “plated” or applied fuse the dry lubricant to the surface and produce a most in a lubricating manner but act as discreet, nonlubricating, 50 Superior dry-lubricated surface. Peening in itself is a desir i.e., abrasive, particles when in a dispersion. Even the dry able and Worthwhile process which induces surface com lubrication obtained permitted operation only for a some pression and hardening thereby minimizing the possibility what longer time before seizure. of Surface cracking. Thus, the peening application of a Another more complicated and somewhat successful 55 dry lubricant not only adheres the lubricant to the surface process involving dry lubrication is that in which the dry in a Superior manner, but also improves the basic quality lubricant is admixed with a resin binder and applied to of the surface as a bearing surface. surfaces to be lubricated. This process requires undersized Burnishing and peening are illustrative of the force parts since the binder and lubricant add a noticeable in generating means which may be used to impact the dry crease in dimensions to the part. Also, the binders usually 60 lubricant upon the surface. used must be baked at relatively high temperatures to It has been found most advantageous and economical cure the binder and gain the required strength therefrom. to initially adhere a dry lubricant to a peening particle. However, since the binder is normally organic in nature, This is done by merely admixing the peening particles, operating temperatures of the thus lubricated surface are which are often quite small in size, with the dry lubricant. limited by the decomposition temperature of the binder, 65 The coated peening particles are then propelled at the which is usually substantially lower than that at which surface at a very high velocity. Upon impacting with the the lubricant or surface will fail. Since the binder and surface, the dry lubricant is forced onto the surface and lubricant produce a definite, finite coating, it is not un fused thereto. usual for film particles to loosen during operation. These Dry lubricants are, as is well known in the art, solid particles are of rather substantial size and can cause 70 materials which facilitate movement between contacting jamming and extreme wear in bearings, cams, and other surfaces by providing lubrication. close tolerance-bearing surfaces. Typical of the dry lubricants useful in the instant inven 3,574,658 3. 4 tion, are molybdenum disulfide, tungsten disulfide, tita ing the surface using microspheres propelled by a high nium disulfide, molybdenum diselenide, tungsten diselen velocity air blast. The two treated surfaces were formed ide, niobium diselenide, and molybdenum ditelluride. As into discs and tested in a vacuum by rotating the discs will be recognized by those skilled in the art, the method with pins of equal area and loading bearing thereupon. It of the instant invention is applicable to a number of dry was found that surface B, treated by the peening process, lubricants. The results obtainable with the preferred em displayed a resistance to wear six times that displayed by bodiments of molybdenum disulfide and tungsten disul surface A which was treated by the burnishing process. fide, have been superior. The operating conditions of the instant invention are EXAMPLE II not critical and, other than the step of interposing the dry O Two 303 stainless steel surfaces were treated in man lubricant between the peening particle and the surface, ners identical to that of Example I. It was found that the are essentially the same as the well known and conven peened surface displayed wear properties superior to the tional requirements for ordinary peening of a surface. burnished surface by a factor of 60 when tested in a That is, temperature is not a critical factor and the oper WaCl. ation is merely continued until the entire surface has been Further, it was noted in both of the examples that thoroughly peened. Peening apparatus utilizing micro the wear properties of the peened surfaces improved dur spheres is preferred in order that the surface roughness ing testing while the burnished surfaces degraded. This is of the bearing surface is not objectionable. The micro attributed to the galling of the burnished surfaces because spheres, or balls, make only a very small impression upon of insufficient lubrication while the peened surfaces merely the surface and do not materially roughen it. Apparatus polished because of proper lubrication. which propels the balls with air has been found useful. Cutting apparatus using this propulsion mechanism is EXAMPLE III operable with microspheres substituted for the conven Spur gears of 303 stainless steel having 3/8 inch face tional abrasive. The minor depressions which do result were dry-lubricated by coating molybdenum disulfide on are often advantageous in that they serve as reservoirs for to glass microspheres of between 50 and 100 microns lubricant.
Load more

Recommended publications
  • Effects of Metal Contacts and Doping for High
    TW-P061 Effects of metal contacts and doping for high-performance field-effect transistor based on tungsten diselenide (WSe2) Seo-Hyeon Jo and Jin-Hong Park School of Electronics and Electrical Engineering, Sungkyunkwan University, Suwon 440-746, Korea Transition metal dichalcogenides (TMDs) with two-dimensional layered structure, such as molybdenum disulfide (MoS2) and tungsten diselenide (WSe2), are considered attractive materials for future semiconductor devices due to its relatively superior electrical, optical, and mechanical properties. Their excellent scalability down to a monolayer based on the van der Waals layered structure without surface dangling bonds makes semiconductor devices based on TMD free from short channel effect. In comparison to the widely studied transistor based on MoS2, researchs focusing on WSe2 transistor are still limited. WSe2 is more resistant to oxidation in humid ambient condition and relatively air-stable than sulphides such as MoS2. These properties of WSe2 provide potential to fabricate high-performance filed-effect transistor if outstanding electronic characteristics can be achieved by suitable metal contacts and doping phenomenon. Here, we demonstrate the effect of two different metal contacts (titanium and platinum) in field-effect transistor based on WSe2, which regulate electronic characteristics of device by controlling the effective barreier height of the metal-semiconductor junction. Electronic properties of WSe2 transistor were systematically investigated through monitoring of threshold voltage shift, carrier concentration difference, on-current ratio, and field-effect mobility ratio with two different metal contacts. Additionally, performance of transistor based on WSe2 is further enhanced through reliable and controllable n-type doping method of WSe2 by triphenylphosphine (PPh3), which activates the doping phenomenon by thermal annealing process and adjust the doping level by controlling the doping concentration of PPh3.
    [Show full text]
  • Two-Dimensional Material-Based Colorimetric Biosensors: a Review
    biosensors Review Two-Dimensional Material-Based Colorimetric Biosensors: A Review Danzhu Zhu, Bin Liu and Gang Wei * College of Chemistry and Chemical Engineering, Qingdao University, Qingdao 266071, China; [email protected] (D.Z.); [email protected] (B.L.) * Correspondence: [email protected]; Tel.: +86-150-6624-2101 Abstract: Two-dimensional (2D) materials such as graphene, graphene oxide, transition metal oxide, MXene and others have shown high potential for the design and fabrication of various sensors and biosensors due to their 2D layered structure and unique properties. Compared to traditional fluorescent, electrochemical, and electrical biosensors, colorimetric biosensors exhibit several ad- vantages including naked-eye determination, low cost, quick response, and easy fabrication. In this review, we present recent advances in the design, fabrication, and applications of 2D material-based high-performance colorimetric biosensors. Potential colorimetric sensing mechanisms and optimal material selection as well as sensor fabrication are introduced in brief. In addition, colorimetric biosensors based on different 2D materials such as graphene, transition metal dichalcogenide/oxide, MXenes, metal–organic frameworks, and metal nanoplates for the sensitive detection of DNA, proteins, viruses, small molecules, metallic ions, and others are presented and discussed in detail. This work will be helpful for readers to understand the knowledge of 2D material modification, nanozymes, and the synthesis of hybrid materials; meanwhile, it could be valuable to promote the design, fabrication, and applications of 2D material-based sensors and biosensors in quick bioanalysis and disease diagnostics. Keywords: 2D materials; nanoparticles; nanozymes; hybrid materials; colorimetric biosensors Citation: Zhu, D.; Liu, B.; Wei, G. Two-Dimensional Material-Based Colorimetric Biosensors: A Review.
    [Show full text]
  • Growth of Two-Dimensional Molybdenum Disulfide Via Chemical Vapor Deposition
    Wright State University CORE Scholar Browse all Theses and Dissertations Theses and Dissertations 2019 Growth of Two-Dimensional Molybdenum Disulfide via Chemical Vapor Deposition Zachary Durnell Ganger Wright State University Follow this and additional works at: https://corescholar.libraries.wright.edu/etd_all Part of the Engineering Science and Materials Commons Repository Citation Ganger, Zachary Durnell, "Growth of Two-Dimensional Molybdenum Disulfide via Chemical aporV Deposition" (2019). Browse all Theses and Dissertations. 2174. https://corescholar.libraries.wright.edu/etd_all/2174 This Thesis is brought to you for free and open access by the Theses and Dissertations at CORE Scholar. It has been accepted for inclusion in Browse all Theses and Dissertations by an authorized administrator of CORE Scholar. For more information, please contact [email protected]. GROWTH OF TWO-DIMENSIONAL MOLYBDENUM DISULFIDE VIA CHEMICAL VAPOR DEPOSITION A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Materials Science and Engineering By ZACHARY DURNELL GANGER B.S.M.S.E. Wright State University, 2015 2019 Wright State University WRIGHT STATE UNIVERSITY GRADUATE SCHOOL March 28th, 2019 I HEREBY RECOMMEND THAT THE THESIS PREPARED UNDER MY SUPERVISION BY Zachary Durnell Ganger ENTITLED Growth of Two Dimensional Molybdenum Disulfide via Chemical Vapor Deposition BE ACCEPTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF Master of Science in Materials Science and Engineering. Committee on Final Examination ______________________________ Hong Huang, Ph.D. ________________________________ Thesis Director Hong Huang, Ph.D. Joseph C. Slater, Ph.D., P.E. ________________________________ Chair, Department of Mechanical and Materials Engineering Yan Zhuang, Ph.D.
    [Show full text]
  • Evaluating the Effect of Varying the Metal Precursor in the Colloidal Synthesis of Mose2 Nanomaterials and Their Application As
    nanomaterials Article Evaluating the Effect of Varying the Metal Precursor in the Colloidal Synthesis of MoSe2 Nanomaterials and Their Application as Electrodes in the Hydrogen Evolution Reaction Zakhele Ndala 1, Ndivhuwo Shumbula 1 , Siyabonga Nkabinde 1, Tshwarela Kolokoto 1, Obakeng Nchoe 1, Poslet Shumbula 2, Zikhona N. Tetana 1,3,4, Ella C. Linganiso 1,3,4, Siziwe S. Gqoba 1,* and Nosipho Moloto 1,* 1 Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa; [email protected] (Z.N.); [email protected] (N.S.); [email protected] (S.N.); [email protected] (T.K.); [email protected] (O.N.); [email protected] (Z.N.T.); [email protected] (E.C.L.) 2 Department of Chemistry, University of Limpopo Private Bag x1106, Sovenga 0727, South Africa; [email protected] 3 DST/NRF Centre of Excellence in Strong Materials, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa 4 Microscopy and Microanalysis Unit, University of the Witwatersrand, Private Bag 3, Johannesburg, Wits 2050, South Africa * Correspondence: [email protected] (S.S.G.); [email protected] (N.M.); Tel.: +27-11-7176-774 or +27-11-7176-756 (S.S.G.); Fax: +27-11-7176-749 (N.M.) Received: 7 July 2020; Accepted: 24 July 2020; Published: 9 September 2020 Abstract: Herein we report on the use of different metal precursors in the synthesis of MoSe2 nanomaterials in order to control their morphology.
    [Show full text]
  • The Preparation and Properties of Tase2 Single Crystal
    International Journal of Physics and Mathematical Sciences ISSN: 2277-2111 (Online) An Open Access, Online International Journal Available at http://www.cibtech.org/jpms.htm 2016 Vol. 6 (1) January-March, pp. 11-16/Patel and Lakhataria. Research Article SYNTHESIS AND STRUCTURAL ANALYSIS OF NBSE2 SINGLE CRYSTALS *Kaushik R Patel1 and Duhita Lakhataria2 1Biogas Research Center, Mahadevbhai Desai Gramseva Mahavidhyalaya, Gujarat Vidyapith, Sadra 382 320 2Government Polytechnique College, Amadavad *Author for Correspondence ABSTRACT The transition metal dichalcogenides NbS2 and NbSe2 are layer compounds consisting of sandwiches with strong covalent/ionic intra layer bonds and weak Van der Waals interlayer interactions. The NbSe2 single crystals were grown by chemical vapour transport technique (CVT) using iodine as transporting agent. The chemical compositions of the grown crystals were confirmed with the help of energy dispersive analysis by X-ray (EDAX). The structural properties were studied by X- ray diffraction analysis (XRD). The crystals were found to possess hexagonal crystal structure. The lattice parameters, unit cell volume, grain size and X-ray density were computed for this crystal. The results obtained are discussed in detail. Keywords: Crystal Growth, Semiconductor, EDAX, XRD, Lattice Parameters PACS Nos.: 61.50.Nw, 61.10.Nz, 81.40.Tv INTRODUCTION The transition metal dichalcogenides, NbS2 and NbSe2 are layered compounds consisting of sandwiches with strong covalent/ionic intra layer bonds and weak van der Waals interlayer interactions. The stacking sequence of S and Nb are AcA BcB (2H- NbS2 structure) or AbA BcB CaC (3R- MoS2 structure) for NbSe2 several more stacking sequences exist (Lieth et al., 1977; Boswell et al., 1976; Harper, 1977).
    [Show full text]
  • Exploring Optoelectronics Potential of Monolayer Tungsten Diselenide
    60 Technical focus: Optoelectronics Exploring optoelectronics potential of monolayer tungsten diselenide Three groups have recently reported on preliminary experiments with photovoltaic and light-emission effects from pn junctions created using split-gate electrostatic doping. Mike Cooke reports. esearchers are beginning to explore the semi- both convert light into current and current into light. conductor potential of monolayer materials The creation of n- and p-type conductivity in these Rbeyond graphene with hopes of developing devices was achieved electrostatically with a split gate robust devices that are flexible and transparent for beneath the WSe2 monolayer. deployment in wearable formats, interactive displays, Vienna University of Technology [Andreas Pospischil and efficient solar cells. et al, Nature Nanotechnology, vol 9 (2014), p257] An interesting class of materials that has recently come began its fabrication by forming a split gate of titanium/ to the fore is that of few-layer group-VIB transition-metal gold with a 460nm gap on a silicon/silicon dioxide dichalcogenides (TMDs) such as molybdenum disulfide wafer (Figure 1). Gate bonding pads were also formed (MoS2), molybdenum diselenide (MoSe2), tungsten with titanium/gold. The split gate was covered with disulfide (WS2), and tungsten diselenide (WSe2). silicon nitride, except for the bonding pads. The crystal structure consists of the metal atoms WSe2 flakes were exfoliated from bulk material sup- encapsulated between two layers of sulfur/selenium plied by Nanosurf onto a stack of polymer layers on a chalcogenide atoms. The bonding within a monolayer sacrificial silicon substrate. Suitable flakes were identi- is strong while the bonding between monolayers is fied under an optical microscope.
    [Show full text]
  • Flexible, Semi-Transparent Ultrathin Solar Cells 9 March 2014
    Flexible, semi-transparent ultrathin solar cells 9 March 2014 At least since the Nobel Prize in physics was awarded in 2010 for creating graphene, the "two dimensional crystals" made of carbon atoms have been regarded as one of the most promising materials in electronics. In 2013, graphene research was chosen by the EU as a flagship- project, with a funding of one billion euros. Graphene can sustain extreme mechanical strain and it has great opto-electronic properties. With graphene as a light detector, optical signals can be transformed into electric pulses on extremely short timescales. For one very similar application, however, graphene is not well suited for building solar cells. "The electronic states in graphene are not very practical for creating photovoltaics", says Thomas This is a microscope photograph of WSe2-samples, Mueller. Therefore, he and his team started to look connected to electrodes. Credit: TU Vienna for other materials, which, similarly to graphene, can arranged in ultrathin layers, but have even better electronic properties. A lot of research has been done on graphene The material of choice was tungsten diselenide: It recently—carbon flakes, consisting of only one layer consists of one layer of tungsten atoms, which are of atoms. As it turns out, there are other materials connected by selenium atoms above and below the too which exhibit remarkable properties if they are tungsten plane. The material absorbs light, much arranged in a single layer. One of them is tungsten like graphene, but in tungsten diselenide, this light diselenide, which could be used for photovoltaics. can be used to create electrical power.
    [Show full text]
  • Chemical Vapor Deposition Growth of Monolayer Mose2 Nanosheets Jonathan C
    Nano Research 1 DOINano 10.1007/s12274Res ‐014‐0147‐z Chemical vapor deposition growth of monolayer MoSe2 nanosheets Jonathan C. Shaw1, Hailong Zhou1, Yu Chen2, Nathan O. Weiss2, Yuan Liu2, Yu Huang2,3, Xiangfeng 1,3 Duan () Nano Res., Just Accepted Manuscript • DOI: 10.1007/s12274-014-0147-z http://www.thenanoresearch.com on January 15, 2014 © Tsinghua University Press 2014 Just Accepted This is a “Just Accepted” manuscript, which has been examined by the peer‐review process and has been accepted for publication. A “Just Accepted” manuscript is published online shortly after its acceptance, which is prior to technical editing and formatting and author proofing. Tsinghua University Press (TUP) provides “Just Accepted” as an optional and free service which allows authors to make their results available to the research community as soon as possible after acceptance. After a manuscript has been technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Please note that technical editing may introduce minor changes to the manuscript text and/or graphics which may affect the content, and all legal disclaimers that apply to the journal pertain. In no event shall TUP be held responsible for errors or consequences arising from the use of any information contained in these “Just Accepted” manuscripts. To cite this manuscript please use its Digital Object Identifier (DOI®), which is identical for all formats of publication. Chemical vapor deposition growth of monolayer MoSe2 nanosheets ,§ ,§ Jonathan C. Shaw1 , Hailong Zhou1 , Yu Chen2, Nathan O. Weiss2, Yuan Liu2, Yu Huang2,3, Xiangfeng Duan1,3,* 1.
    [Show full text]
  • ACS Division of Analytical Chemistry
    ANYL DIVISION OF ANALYTICAL CHEMISTRY P. Bohn and M. Bush, Program Chairs SUNDAY MORNING Section A Placeholder Low-Cost & Open-Source Analytical Chemistry J. P. Grinias, Organizer, Presiding 8:00 . Enabling Real-Time Processing of High-Volume Electrochemical Measurements via Open Source Software. N. Arroyo 8:20 . Open-Source Data Acquisition Devices for Chromatographic Instrumentation. S.W. Foster, E.W. Constans, J.P. Grinias 8:40 . Silicon photomultiplier as a low-cost fluorescence detector for capillary electrophoresis. B. Petersen, N.L. Allbritton 9:00 . Sensitive, selective, and quantitative copper sensor using click-chemistry with gold nanoparticles.. R.M. Cary, I. Monroe, j. holbrook, O. Hess, S. Unser, L. Sagle 9:20 . Glucose Responding Fluorescent Microneedle for An Affordable Continuous Glucose Monitoring. J. Kim, H. YIm, J. Park, H. Choi, B. Lee, S. Lee, M. Lee 9:40 Intermission. 10:00 . Low cost paper-based immunoassays for infectious disease diagnostics. K. Hamad- Schifferli 10:20 . Strength in numbers: A library of chemical color tests improves presumptive identification of illicit drugs and cutting agents.. T. Lockwood, B. Ray, G. Scott, M. Lieberman 10:40 . Chemical fingerprinting of carboxylate anions on low-cost paper supports. Y. Xu, M. Bonizzoni 11:00 . An Analysis of the Quality of Beta-Lactam Antibiotics collected in Nepal. W. Lewis, M. Benjamin 11:20 . Open-access resources for the teaching of analytical chemistry. D.T. Harvey 11:40 . Open-source analytical chemistry in the laboratory and the classroom. J.P. Grinias, J.A. Naese, J. Emig Section B Placeholder Active Learning in the Undergraduate Analytical Chemistry Curriculum (Invited) M.
    [Show full text]
  • United States Patent Office Patented Oct
    3,472,621 United States Patent Office Patented Oct. 14, 1969 2 in yield does not justify the extra effort required to attain 3,472,621 such higher pressures. MOLYBDENUM DISELENDE HAVING A RHOM. As previously stated, the practice of this invention re BOHEDRAL CRYSTAL STRUCTURE AND METH OD OF PREPARING SAME quires a combination of both pressure and elevated tem Meyer S. Silverman, Norristown, Pa., assignor to Pennsalt peratures to convert the raw materials described above Chemicals Corporation, Philadelphia, Pa., a corpora into the new rhombohedral crystalline form of molyb tion of Pennsylvania denum diselenide. A temperature of at least about 800' No Drawing. Filed July 9, 1965, Ser. No. 470,907 C. is necessary, at least about 1600° C. being preferred. The portion of the term of the patent subsequent The practical upper temperature limit is about 2500 C. to May 28, 1985, has been disclaimed 10 The preferred range of operating temperatures is from Int. Cl. C01b 19/00; C01g 39/00 about 1600 C. to about 2000 C. The product MoSea U.S. Ct. 23-204 11 Claims will contain some hexagonal crystal form of the com pound in addition to the desired rhombohedral crystal form when the synthesis is conducted in the lower range 15 of temperatures, with an increase in temperature favoring ABSTRACT OF THE DISCLOSURE the yield of the rhombohedral form. It has been found Molybdenum diselenide having a rhombohedral crystal that at temperatures above about 1600 C., the product is structure and useful as a specialty lubricant is prepared essentially the rhombohedral crystal form.
    [Show full text]
  • 'Mind the Gap' Between Atomically Thin Materials 24 December 2014, by Walt Mills
    'Mind the gap' between atomically thin materials 24 December 2014, by Walt Mills layer down to the graphene layer, they encountered a surprising amount of resistance. About half of the resistance was caused by the gap, which introduced a large barrier, about 1 electron volt, to the electrons trying to move between layers. This energy barrier could prove useful in designing next generation electronic devices, such as vertical tunneling field effect transistors, said Robinson. The interest in this type of material arose with the discovery of methods to make single layer graphite. Colorized TEM image of tungsten disulfide triangles The Penn State researchers use a more scalable (black) growing on graphene substrate (green). Credit: method than early graphene makers—chemical UT Dallas/Penn State vapor deposition—to deposit a single layer of crystalline tungsten diselenide on top of a few layers of graphene grown from silicon carbide. When it comes to engineering single-layer atomic Although graphene research exploded in the last structures, "minding the gap" will help researchers decade, many similar solids exist that can combine create artificial electronic materials one atomic to create entirely new artificial materials with layer at a time, according to a team of materials unimaginable properties. scientists. The researchers discovered that the tungsten The gap is a miniscule vacuum that researchers in diselenide layer grew in perfectly aligned triangular Penn State's Center for 2-Dimensional and islands 1 to 3 microns in size that slowly coalesced Layered Materials believe is an energy barrier into a single crystal up to 1 centimeter square. They keeping electrons from easily crossing from one reported their results in Nano Letters.
    [Show full text]
  • International Roadmap for Devices and Systems
    INTERNATIONAL ROADMAP FOR DEVICES AND SYSTEMS 2020 EDITION BEYOND CMOS THE IRDS IS DEVISED AND INTENDED FOR TECHNOLOGY ASSESSMENT ONLY AND IS WITHOUT REGARD TO ANY COMMERCIAL CONSIDERATIONS PERTAINING TO INDIVIDUAL PRODUCTS OR EQUIPMENT. ii © 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. THE INTERNATIONAL ROADMAP FOR DEVICES AND SYSTEMS: 2020 COPYRIGHT © 2020 IEEE. ALL RIGHTS RESERVED. iii Table of Contents Acknowledgments .............................................................................................................................. vi 1. Introduction .................................................................................................................................. 1 1.1. Scope of Beyond-CMOS Focus Team .............................................................................................. 1 1.2. Difficult Challenges ............................................................................................................................ 2 1.3. Nano-information Processing Taxonomy........................................................................................... 4 2. Emerging Memory Devices ..........................................................................................................
    [Show full text]