New Optical Microscope for the Observation of Microstructure in High Purity Metals.

Effect of heat treatment on the microstructure and mechanical properties of high purity MA2-1(Mg-5wt.%Al-1wt.%Zn-0.4wt.%Mn) alloy sheet were investigated. X-ray diffraction analysis indicated that the microstructure of high purity MA2-1 alloy sheet annealed consisted of α-Mg solid solution, β (Mg17Al12) phase and Al-Mn phases such as Al6Mn and Al10Mn3. β phase dissolved into α-Mg solid solution during the solution treatment and formed supersaturated α-Mg solid solution. After aging at the temperatures of 423 K, 473 K and 523 K for 12 hours, β phase precipitated from the supersaturated α-Mg solid solution. Optical microscope observation found that the grain size of the MA2-1 alloy sheet became larger after heat treatment. As a result, the mechanical properties of the MA2-1 alloy sheet such as the tensile strength and yield strength declined after the heat treatment.

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Synthesis of Porous Anodic Alumina on Aluminium Manganese Alloys

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1109.78 ◽

2015 ◽

Vol 1109 ◽

pp. 78-82

Author(s):

Chun Hong Voon ◽

Mohd Nazree Derman ◽

U. Hashim ◽

Kai Loong Foo ◽

Seng Teik Ten

Keyword(s):

Aluminium Alloy ◽

High Purity ◽

Manganese Content ◽

Secondary Phase ◽

Optical Microscope ◽

Anodic Alumina ◽

Porous Anodic Alumina ◽

Aluminium Substrate ◽

Purity Aluminium ◽

High Purity Aluminium

In this study, porous anodic alumina was formed on aluminium alloy substrate with increasing manganese content, from high purity aluminium with 0 wt% Mn to aluminium alloy with 2.0 wt% manganese by anodizing. Substrates were anodized at 50 V in 0.3 M oxalic acid of 15°C for 60 minutes. Images from the optical microscope revealed that no secondary phase existed in high purity aluminium and aluminium substrate with 0.5 wt% manganese while two phases were observed when the manganese contents were higher than 0.5 wt%. Element dispersive X ray spectroscopy spot analysis suggested that the secondary phase consists of both aluminium and manganese. Well ordered porous anodic alumina was obtained on high purity aluminium and aluminium substrate with 0.5 wt% manganese while pore arrangement of porous anodic alumina was significant disturbed when aluminium alloys with manganese contents higher than 0.5 wt% were anodized.

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HIGH TEMPERATURE GAS NITRIDING TREATMENT OF AISI 430 USING LOW AND HIGH PURITY NITROGEN GAS

ROTASI ◽

10.14710/rotasi.18.3.65-68 ◽

2016 ◽

Vol 18 (3) ◽

pp. 65

Author(s):

Agus Suprihanto

Keyword(s):

Stainless Steel ◽

High Temperature ◽

Nitrogen Atom ◽

High Purity ◽

Optical Microscope ◽

Nitrogen Gas ◽

Metallographic Examination ◽

Gas Nitriding ◽

Aisi 430 ◽

High Temperature Gas

The properties of stainless steels can be improved by high temperature gas nitriding (HTGN) treatment. The improving of their properties are obtained from nitrogen atom which diffuse into stainless steel. Nitrogen gas is the main source of nitrogen atom on the HTGN treatment. Generally, these treatment use high purity of nitrogen gas. The aim of this research is to investigate the effect of nitrogen gas purity on the HTGN treatment for AISI 430. Stainless steel AISI 430 plate 2 mm thick was processed by HTGN treatment. The specimens was exposed at nitrogen gas atmosphere at temperature 1200oC and held for 2 hours prior quenching in water. The treatment used industrial/welding grade (99.5%) as low nitrogen gas purity and ultra high purity (UHP) grade (99.999%) as high nitrogen gas purity. The vickers micro-hardness test was conducted to evaluate the hardness distribution from surface into middle section of the specimens before and after treatment. Light optical microscope was applied to examine the microstructure of specimens after treatment. Metallographic examination shows both treatments using low and high purity gas have the same grain size. However HTGN treatment using low purity of nitrogen gas produces hardness slightly lower than the high purity. This is due the high content of impurity of the low purity gas that reduces the partial pressure of nitrogen gas. Another effect of impurity is the reaction between nitrogen gas and its impurity especially oxygen gas. These reactions reduce the amount of free nitrogen atom which diffuses on the stainless steel.

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The comparison pack carburizing-nitriding SUS 316 with gas type Welding Grade and Ultra High Purity

EUREKA Physics and Engineering ◽

10.21303/2461-4262.2021.001839 ◽

2021 ◽

pp. 119-126

Author(s):

Bambang Sulistiyono ◽

Yudy Surya Irawan ◽

Agus Suprapto ◽

Rudy Soenoko

Keyword(s):

Activated Carbon ◽

High Purity ◽

Barium Carbonate ◽

Substrate Surface ◽

Optical Microscope ◽

Nitride Layer ◽

Test Material ◽

Elemental Content ◽

Ultra High Purity ◽

Teak Wood

The paper discusses the comparison of pack carburizing-nitriding SUS 316 with gas Nitrogen. The purpose of this study was to increase the hardness and corrosion resistance of SUS 316. The research used a pack carburizing-nitriding method with gas type Welding Grade (WG) and Ultra High Purity (UHP). The pack carburizing process uses teak wood activated carbon and barium carbonate as a bio-photo catalyst. The specimens were put into a Sealed Steel Container containing teak wood activated carbon, with a depth of 1 cm below the activated carbon's surface. The test material is then heated until it reaches 850 °C and is held for 1 hour in a heating furnace. Furthermore, the nitriding process, the specimen is put into a tightly closed nitrogen tube, then nitrogen gas flows until the pressure reaches 41 bar and is held for 24 hours. They are using Welding Grade (WG) and Ultra High Purity (UHP) gas types. Furthermore, microVickers hardness testing, optical microscope, and Scan Electron Microscope (SEM) were carried out. The results of the study include a. There was an increase in violence by 41.7 % for UHP and WG (17.3 %). b. The formation of nitride compounds and carbon dissipation on the specimen surface in the UHP carburizing-nitriding pack treatment is more than WG. The formation of a nitride layer is indicated by its fine and dense morphology and film bonding to the substrate. The chemical composition affects the diffusivity of nitrogen atoms in modifying the surface layer of the substrate. The higher the nitride compound formed, the smoother the substrate surface. Also, with UHP treatment, the lower the elemental content of Cr makes SUS 316 more resistant to corrosion. So that SUS 316 UHP can be recommended for use as an implant material

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Observations oh Nucleation and Growth of Voids in Nickel

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069065 ◽

1970 ◽

Vol 28 ◽

pp. 414-415

Author(s):

J. L. Brimhall ◽

H. E. Kissinger ◽

B. Mastel

Keyword(s):

High Purity ◽

Growth Stage ◽

Elevated Temperatures ◽

Early Growth ◽

Nucleation And Growth ◽

Pure Nickel ◽

Different Temperatures ◽

Total Fluence ◽

Neutron Exposure ◽

Growth Of Voids

Some information on the size and density of voids that develop in several high purity metals and alloys during irradiation with neutrons at elevated temperatures has been reported as a function of irradiation parameters. An area of particular interest is the nucleation and early growth stage of voids. It is the purpose of this paper to describe the microstructure in high purity nickel after irradiation to a very low but constant neutron exposure at three different temperatures.Annealed specimens of 99-997% pure nickel in the form of foils 75μ thick were irradiated in a capsule to a total fluence of 2.2 × 1019 n/cm2 (E > 1.0 MeV). The capsule consisted of three temperature zones maintained by heaters and monitored by thermocouples at 350, 400, and 450°C, respectively. The temperature was automatically dropped to 60°C while the reactor was down.

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Preparation and characterisation of vanadium pentoxide supported rhodium catalyst

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010010679x ◽

1988 ◽

Vol 46 ◽

pp. 946-947

Author(s):

A. Legrouri

Keyword(s):

Aqueous Solution ◽

Thermal Decomposition ◽

Physicochemical Properties ◽

Surface Area ◽

Vanadium Pentoxide ◽

High Purity ◽

Gas Adsorption ◽

Rhodium Catalyst ◽

Optical Methods ◽

Reducible Oxides

The industrial importance of metal catalysts supported on reducible oxides has stimulated considerable interest during the last few years. This presentation reports on the study of the physicochemical properties of metallic rhodium supported on vanadium pentoxide (Rh/V2O5). Electron optical methods, in conjunction with other techniques, were used to characterise the catalyst before its use in the hydrogenolysis of butane; a reaction for which Rh metal is known to be among the most active catalysts.V2O5 powder was prepared by thermal decomposition of high purity ammonium metavanadate in air at 400 °C for 2 hours. Previous studies of the microstructure of this compound, by HREM, SEM and gas adsorption, showed it to be non— porous with a very low surface area of 6m2/g3. The metal loading of the catalyst used was lwt%Rh on V2Q5. It was prepared by wet impregnating the support with an aqueous solution of RhCI3.3H2O.

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Some early history of replica techniques for electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100130018 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1076-1077

Author(s):

Robert M. Fisher

Keyword(s):

Thin Film ◽

Electron Microscopy ◽

Optical Microscope ◽

Early History ◽

Bulk Materials ◽

Thin Sections ◽

Transmission Electron ◽

Reflected Light ◽

History Of ◽

Electron Microscopes

By 1940, a half dozen or so commercial or home-built transmission electron microscopes were in use for studies of the ultrastructure of matter. These operated at 30-60 kV and most pioneering microscopists were preoccupied with their search for electron transparent substrates to support dispersions of particulates or bacteria for TEM examination and did not contemplate studies of bulk materials. Metallurgist H. Mahl and other physical scientists, accustomed to examining etched, deformed or machined specimens by reflected light in the optical microscope, were also highly motivated to capitalize on the superior resolution of the electron microscope. Mahl originated several methods of preparing thin oxide or lacquer impressions of surfaces that were transparent in his 50 kV TEM. The utility of replication was recognized immediately and many variations on the theme, including two-step negative-positive replicas, soon appeared. Intense development of replica techniques slowed after 1955 but important advances still occur. The availability of 100 kV instruments, advent of thin film methods for metals and ceramics and microtoming of thin sections for biological specimens largely eliminated any need to resort to replicas.

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Near-field scanning optical microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100144644 ◽

1986 ◽

Vol 44 ◽

pp. 642-643

Author(s):

E. Betzig ◽

A. Harootunian ◽

M. Isaacson ◽

A. Lewis

Keyword(s):

Near Field ◽

Optical Microscope ◽

Visible Radiation ◽

Field Methods ◽

Optical Elements ◽

Optical Region ◽

Order Of Magnitude ◽

Nondestructive Imaging ◽

Scanning Optical Microscopy ◽

Near Field Scanning

In general, conventional methods of optical imaging are limited in spatial resolution by either the wavelength of the radiation used or by the aberrations of the optical elements. This is true whether one uses a scanning probe or a fixed beam method. The reason for the wavelength limit of resolution is due to the far field methods of producing or detecting the radiation. If one resorts to restricting our probes to the near field optical region, then the possibility exists of obtaining spatial resolutions more than an order of magnitude smaller than the optical wavelength of the radiation used. In this paper, we will describe the principles underlying such "near field" imaging and present some preliminary results from a near field scanning optical microscope (NS0M) that uses visible radiation and is capable of resolutions comparable to an SEM. The advantage of such a technique is the possibility of completely nondestructive imaging in air at spatial resolutions of about 50nm.

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High-purity Ge x-ray detectors: Sensitivity factors and usefulness

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100136350 ◽

1990 ◽

Vol 48 (2) ◽

pp. 548-548

Author(s):

E. B. Steel

Keyword(s):

High Purity ◽

High Energy ◽

Quantitative Chemical Analysis ◽

Detector Performance ◽

X Ray ◽

Detector Sensitivity ◽

Specimen Holder ◽

Many Instruments ◽

Charge Resolution ◽

Sensitivity Factors

High Purity Germanium (HPGe) x-ray detectors are now commercially available for the analytical electron microscope (AEM). The detectors have superior efficiency at high x-ray energies and superior resolution compared to traditional lithium-drifted silicon [Si(Li)] detectors. However, just as for the Si(Li), the use of the HPGe detectors requires the determination of sensitivity factors for the quantitative chemical analysis of specimens in the AEM. Detector performance, including incomplete charge, resolution, and durability has been compared to a first generation detector. Sensitivity factors for many elements with atomic numbers 10 through 92 have been determined at 100, 200, and 300 keV. This data is compared to Si(Li) detector sensitivity factors.The overall sensitivity and utility of high energy K-lines are reviewed and discussed. Many instruments have one or more high energy K-line backgrounds that will affect specific analytes. One detector-instrument-specimen holder combination had a consistent Pb K-line background while another had a W K-line background.

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Principles of Low-Vacuum SEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100131152 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1304-1305

Author(s):

Klaus-Ruediger Peters

Keyword(s):

New Technologies ◽

High Vacuum ◽

Optical Microscope ◽

Specimen Surface ◽

Electrical Field ◽

Gaseous Environment ◽

New Information ◽

Gas Molecules ◽

New Interactions ◽

Gas Pressures

Only recently it became possible to expand scanning electron microscopy to low vacuum and atmospheric pressure through the introduction of several new technologies. In principle, only the specimen is provided with a controlled gaseous environment while the optical microscope column is kept at high vacuum. In the specimen chamber, the gas can generate new interactions with i) the probe electrons, ii) the specimen surface, and iii) the specimen-specific signal electrons. The results of these interactions yield new information about specimen surfaces not accessible to conventional high vacuum SEM. Several microscope types are available differing from each other by the maximum available gas pressure and the types of signals which can be used for investigation of specimen properties.Electrical non-conductors can be easily imaged despite charge accumulations at and beneath their surface. At high gas pressures between 10-2 and 2 torr, gas molecules are ionized in the electrical field between the specimen surface and the surrounding microscope parts through signal electrons and, to a certain extent, probe electrons. The gas provides a stable ion flux for a surface charge equalization if sufficient gas ions are provided.

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