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Glossary of MinSE


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A

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A treatment mainly applied to aluminium, magnesium and titanium alloys, whereby the natural passive surface oxide of these materials is thickened considerably by a process of anodic oxidation conducted in several proprietry electrolytic solutions. The oxide layers offer some durability against wear and corrosion and can be coloured by dyes for aesthetic appeal. One of the highest volume products is extruded aluminium forms used in window frames and other architectural applications. In recent years anodising has been exploited as a means of producing alumina based membranes for use in separation of gaseous mixtures used in the chemical processing industries.
Hungary flag Eloxálás
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antifriction coatingAny coating that can be applied, especially to bearing surfaces, for the reduction of sliding friction and wear. Traditional metallic coatings used in lubricated bearing systems include lead, indium, silver and tin alloys. For dry lubrication systems, such as those used in satellite mechanisms (durability in outer space), ceramic coatings like TiC have found favour. Other low friction ceramic coatings, like TiN, ZrO2 and Al2O3, are being evaluated for the bearing surfaces of artificial hip and knee joints.
Hungary flag Súrolódásmentes bevonat
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Sometimes designated ALE. A comparatively new technique. The first experimental investigations were made in 1974 by Suntola and Antson, while the first industrial evaluation was made by the Lohja Corporation (Finland) in respect to the deposition of ZnS for use as electroluminescent displays. Other materials that are deposited include CdTe, GaAs, GaP, Ta2O5, and ZnSe. ALE seeks to deposit uniform, defect free layers of material that are only a few atomic layers in thickness onto oxide based substrates used for solid state electronic devices. The constituents of the coating are reacted precisely at the surface and become attached and formed through a repititive cycle of chemisorbtion and desorbtion; in the example of ZnS sequential atomic layers of Zn and S are alternately built up. For further details consult the review of Simpson et al, Surface Engineering, 3, No4, 1987, pp 343-348.
Hungary flag Atomos réteg-epitaxia
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A term invoked by Trent to explain the wear of cemented carbide tools, whereby singular grains or groups of grains become torn or "plucked" from the tool contact faces during metal cutting. Attrition wear is especially prevalent at relatively low cutting speeds when the metal chip forms a seized deposit around the tool cutting edge, termed a "built-up-edge", which periodically breaks away from the tool, and takes with it fragments of tool material. Hence, the chip-tool contact is of an intermittent nature. Even at higher cutting speeds, where the built-up-edge no longer forms, attrition wear can take place on the flank faces of cemented carbide tools, especially those containing high volume fractions of (W,Ti,Ta,Nb)C phase or having a relatively coarse WC grain size (≈3-5 µm). For further details see E. M. Trent: 'Metal Cutting', 3rd ed; 1992, London, Butterworths.
Hungary flag Kopás
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An electron spectroscopy method useful for obtaining chemical compositonal information of the outermost 10 atomic layers or so of a surface. The technique is carried out under ultra-high vacuum conditions (≈10-9 torr), and uses a low power density electron beam to "probe" the sample surface. During irradiation by the beam, characteristic auger electrons are emitted by the sample. Depth profiling can be achieved by the conjoint action of an ion beam gun, which directs argon ions at the sample surface and strips the sample surface of, for example, the natural external passive layer. The sample must be electrically conducting to assure satisfactory coupling by the electron beam. Hence, the method does not lend itself to the interrogation of ionic or covalently bonded ceramic surfaces (since they are non-conducting).
Hungary flag Auger elektron spektroszkópos módszer

B

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One type of source deployed in magnetron sputter deposition. The balanced magnetron is a standard magnetron sputter cathode in which the outer magnetic field is balanced to match that of the inner field. Until the mid-late 1980's all magnetron cathodes were of this design. The term has been invoked to differentiate this type of magnetron from the more recently developed unbalanced magnetron. Balanced magnetrons are still widely used for coating semi-conductor devices but are less popular for the deposition of tribological coatings, since the substrate current density is low and auxiliary hating is needed to assure adequate coating adherence. Also see unbalanced magnetron.

Hungary flag Kiegyensúlyozott magnetron

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A controlled polishing technique enabling the ready measurement of coating thickness; especially for thin (≈ 1-10µm) ceramic coatings. A hardened steel or cemented carbide ball, ≈ 20 to 50 mm diameter, is coated with 1µm diamond paste and rotated on the coated surface until the coating is worn through. Since the diameter of the ball is known, a taper section of known geometry is obtained. The width of the wear scar is easily measured with a light-optical microscope and the coating thickness calculated. The method gives good results for coatings that are 1 µm thick or greater.

Hungary flag Kráterképződéses teszt

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The father of modern surface engineering who pioneered the exploitation of glow discharge plasmas for plasma nitriding and sputter deposition. His patents, originating during the 1930's and continuing through to the 1960's can be regarded as truly seminal. He was born of German parents in Amsterdam on 31st July 1896 and died in Zurich on 30th December 1966. Much of his early life was spent in Munster, N.R.W., Germany. He subsequently established a small research and development company called Gesellschaft zur Forderung der Glimmentladungsforschung whose sole goal was to achieve the industrial exploitation of plasma assisted techniques. Further impetus was provided by a subsequent collaboration with Ionon of Koln (Cologne) which in turn lead to the foundation of Klockner Ionon who transferred plasma nitriding on a major scale to the European and Norh American manufacturing sectors. In later years many other companies emulated the ideas of Berghaus, and today plasma techniques, especially plasma nitriding, is practised in all technologically advanced countries.

Hungary flag Berghaus, Bernhard

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Hardness determined using a triangular base pyramid diamond indenter. The included angle at the apex of the pyramid is 65°, i.e., the angle between the vertical axis and each of the three faces. The Berkovich indenter is proving popular in nanoindentaion hardness.

Hungary flag Berkovich keménység

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A proprietry gaseous austenitic nitrocarburising treatment.
Hungary flag Beta

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