scholarly journals Redistribution and Effect of Various Elements on the Morphology of Primary Graphite in Cast Iron

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
J. Lacaze ◽  
N. Valle ◽  
K. Theuwissen ◽  
J. Sertucha ◽  
B. El Adib ◽  
...  
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Spheroidal Graphite ◽  
Metallic Elements ◽  
Controlled Cooling ◽  
Cast Irons ◽  
Bulk Graphite ◽  
Distribution Of Elements ◽  
Graphite Growth ◽  
Secondary Ion

It has been shown repeatedly that many elements present as traces or at low level can affect graphite shape in cast irons. As part of a long term project aimed at clarifying the growth and the alteration of spheroidal graphite, a study on the effect of a few elements (Cu, Sn, Sb, and Ti) on primary graphite growth was undertaken and analysed with reference to an alloy without any such additions. This work was performed by remelting alloys in graphite crucibles thus saturating the melt in carbon and enabling primary graphite to grow by controlled cooling of the melt above the eutectic temperature. Primary graphite growth in the reference alloy was observed to be lamellar, while the added elements were found to affect bulk graphite and to modify its outer shape, with Sb leading eventually to rounded agglomerates together with wavy lamellae. Secondary ion mass spectrometry was used to analyze the distribution of elements, and no build-up of trace elements at the graphite surface could be observed. Instead, it is established that the perturbation of bulk graphite is associated with inhomogeneous distribution of metallic elements inside graphite precipitates.

Interface Reactions in LiNbO3 Based Optoelectronics Devices

2000 ◽  
Vol 654 ◽  
Author(s):  
Hirotoshi Nagata ◽  
Yasuyuki Miyama ◽  
Kaoru Higuma ◽  
Yoshihiro Hashimoto ◽  
Futoshi Yamamoto ◽  
...  
Keyword(s):  
Communication Systems ◽  
High Speed ◽  
Secondary Ion Mass Spectrometry ◽  
Optical Fiber Communication ◽  
Fiber Communication ◽  
Long Term Stability ◽  
Interface Reactions ◽  
Study Results ◽  
Secondary Ion

AbstractWe present secondary ion mass spectrometry (SIMS) study results on interfaces of LiNbO3 based optoelectronic devices, which have been performed in order to examine the cause of device failures. The devices are widely used in current high-speed optical fiber communication systems, and such investigation from a materials-viewpoint is important to improve the device quality. Especially, the device long-term stability is strongly affected by alkali-contaminants diffused into the SiO2 buffer layer of device, and here we confirmed that an adoption of common Si3N4 passivation is effective in preventing the process-induced contamination without any influence to device performance.

Further use of Secondary Ion Mass Spectrometry in the Study of Graphite Morphology Control TN Cast Irons

1984 ◽  
Vol 34 ◽  
Author(s):  
S. E. Franklin ◽  
R. A. Stark
Keyword(s):  
Mass Spectrometry ◽  
Cast Iron ◽  
Secondary Ion Mass Spectrometry ◽  
Current Paper ◽  
Cast Irons ◽  
Preliminary Results ◽  
Graphite Morphology ◽  
Ion Mass Spectrometry ◽  
Sims Analysis ◽  
Secondary Ion

ABSTRACTIn a previous publication, preliminary results obtained using secondary ion mass spectrometry to determine selective elemental distributions in cast iron were reported. These results were used to tentatively assign possible roles to the important solutes in controlling the graphite morphology. The current paper is a continuation of this work and presents the most recent results of the SIMS analysis.

scholarly journals Metastable Eutectoid Transformation in Spheroidal Graphite Cast Iron: Modeling and Validation

Metals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 550 ◽  
Author(s):  
Fernando D. Carazo ◽  
Laura N. García ◽  
Diego J. Celentano
Keyword(s):  
Initial Conditions ◽  
Spheroidal Graphite ◽  
Eutectoid Transformation ◽  
Cast Irons ◽  
Spheroidal Graphite Cast Iron ◽  
Graphite Cast Iron ◽  
Proposed Model ◽  
Three Phase ◽  
Microstructural Model ◽  
Graphite Growth

This paper presents a new microstructural model of the metastable eutectoid transformation in spheroidal graphite cast irons. The model takes into account the nucleation and growth of pearlite nodules. The nucleation is assumed to be continuous and dependent on the metastable undercooling associated with the upper limit of the three-phase field, while the growth rate is considered to be ruled by the silicon partitioning between ferrite and cementite at the pearlite/austenite front. The initial conditions for the metastable transformation are obtained from a microstructural simulation of solidification, graphite growth, and stable eutectoid transformation. These microstructural models are coupled with the thermal balance solved at a macroscopic level via the finite element method. The experimental validation of the metastable eutectoid model achieved by comparison with measured values of ferrite, graphite, and pearlite fractions at the end of the cooling process demonstrates the sound predictive capabilities of the proposed model.

scholarly journals Continuous Modification of Cast Iron By the FLORET Method

2012 ◽  
Vol 12 (3) ◽  
pp. 43-48
Author(s):  
A. Hanus ◽  
P. Hanusová
Keyword(s):  
Cast Iron ◽  
Basic Structure ◽  
Operating Conditions ◽  
Spheroidal Graphite ◽  
Cast Irons ◽  
Advantages And Disadvantages ◽  
Operational Tests ◽  
Materials Used ◽  
Theoretical Foundations

Abstract Increasing demands on the utility properties of materials used for castings have led to the production of cast iron with a modified shape of graphite, where the required properties are achieved by a change in graphite shape, its size and layout, and a change in the basic structure of the metal. This paper is focused on the continuous method of producing spheroidal graphite FLOTRET. In the introductory section is summarized the theoretical foundations of the secondary treatment of cast irons, especially the FLOTRET flow method, describes the advantages and disadvantages of the method. The practical part is divided into laboratory and operational tests. Laboratory experiments were conducted on a laboratory-type modifier FLOTRET chamber, which was designed and hydraulically optimized. Experiments were focused on the effects of pressure altitude and amount of modifier on the residual values of magnesium, as conditions for a successful modification. The method was tested in two foundries under operating conditions and in one of them was observed a long-term modification process.

An Explanation for the Environmental Sensitivity of Ni3Al

1998 ◽  
Vol 552 ◽  
Author(s):  
D. B. Lillig ◽  
D. Legzdina ◽  
I. M. Robertson ◽  
H. K. Birnbaum
Keyword(s):  
Mass Spectrometry ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Secondary Ion Mass Spectrometry ◽  
Environmental Sensitivity ◽  
Boron Segregation ◽  
Boron Doped ◽  
Distribution Of Elements ◽  
Free Material ◽  
Secondary Ion

ABSTRACTSecondary Ion Mass Spectrometry has been used to study the distribution of elements in and near grain boundaries in boron-free and boron-doped Ni76Al24 alloys with and without ∼220 wt. ppm of deuterium. In boron-free alloys, sulfur was distributed about the grain boundaries in both deuterium- free and deuterium-charged samples. The distribution of deuterium followed that of sulfur and was segregated to grain boundaries. In the boron-doped material, sulfur was not found at most grain boundaries in the uncharged material, but was in the charged material. No deuterium was found at the grain boundaries in the boron-doped material. It is proposed that in the boron-free material it is the synergistic effect of sulfur and hydrogen that is responsible for the environmental sensitivity of this alloy. In boron-doped material, boron segregation to the grain boundary prevents sulfur, and to some extent hydrogen, segregating to the grain boundary.

Aspects of high-resolution imaging with a scanning ion microprobe

1986 ◽  
Vol 44 ◽  
pp. 750-751
Author(s):  
R. Levi-Setti ◽  
J. M. Chabala ◽  
Y. L. Wang
Keyword(s):  
Metal Ion ◽  
Secondary Ion Mass Spectrometry ◽  
Chromatic Aberration ◽  
Ion Source ◽  
Ion Microprobe ◽  
Emission Pattern ◽  
Intrinsic Resolution ◽  
Resolution Imaging ◽  
20 Nm ◽  
Secondary Ion

We have shown the feasibility of 20 nm lateral resolution in both topographic and elemental imaging using probes of this size from a liquid metal ion source (LMIS) scanning ion microprobe (SIM). This performance, which approaches the intrinsic resolution limits of secondary ion mass spectrometry (SIMS), was attained by limiting the size of the beam defining aperture (5μm) to subtend a semiangle at the source of 0.16 mr. The ensuing probe current, in our chromatic-aberration limited optical system, was 1.6 pA with Ga+ or In+ sources. Although unique applications of such low current probes have been demonstrated,) the stringent alignment requirements which they imposed made their routine use impractical. For instance, the occasional tendency of the LMIS to shift its emission pattern caused severe misalignment problems.

How SIMS microscopy can be used in medicine

1992 ◽  
Vol 50 (2) ◽  
pp. 1602-1603
Author(s):  
Philippe Fragu
Keyword(s):  
Mass Spectrometry ◽  
Biomedical Applications ◽  
Secondary Ion Mass Spectrometry ◽  
Chemical Elements ◽  
Biological Applications ◽  
The Past ◽  
Potential Source ◽  
Secondary Ion ◽  
Chemical Integrity ◽  
Scientific Endeavour

The identification, localization and quantification of intracellular chemical elements is an area of scientific endeavour which has not ceased to develop over the past 30 years. Secondary Ion Mass Spectrometry (SIMS) microscopy is widely used for elemental localization problems in geochemistry, metallurgy and electronics. Although the first commercial instruments were available in 1968, biological applications have been gradual as investigators have systematically examined the potential source of artefacts inherent in the method and sought to develop strategies for the analysis of soft biological material with a lateral resolution equivalent to that of the light microscope. In 1992, the prospects offered by this technique are even more encouraging as prototypes of new ion probes appear capable of achieving the ultimate goal, namely the quantitative analysis of micron and submicron regions. The purpose of this review is to underline the requirements for biomedical applications of SIMS microscopy.Sample preparation methodology should preserve both the structural and the chemical integrity of the tissue.

Advances in imaging SIMS studies of stained and BrdU-labelled human metaphase chromosomes

1995 ◽  
Vol 53 ◽  
pp. 932-933
Author(s):  
R. Levi-Setti ◽  
J. M. Chabala ◽  
R. Espinosa ◽  
M. M. Le Beau
Keyword(s):  
High Performance ◽  
Secondary Ion Mass Spectrometry ◽  
Analytical Sensitivity ◽  
Metaphase Chromosomes ◽  
Banding Patterns ◽  
Sector Mass Spectrometer ◽  
Staining Methods ◽  
The University ◽  
Secondary Ion ◽  
Better Than

We have shown previously that isotope-labelled nucleotides in human metaphase chromosomes can be detected and mapped by imaging secondary ion mass spectrometry (SIMS), using the University of Chicago high resolution scanning ion microprobe (UC SIM). These early studies, conducted with BrdU- and 14C-thymidine-labelled chromosomes via detection of the Br and 28CN- (14C14N-> labelcarrying signals, provided some evidence for the condensation of the label into banding patterns along the chromatids (SIMS bands) reminiscent of the well known Q- and G-bands obtained by conventional staining methods for optical microscopy. The potential of this technique has been greatly enhanced by the recent upgrade of the UC SIM, now coupled to a high performance magnetic sector mass spectrometer in lieu of the previous RF quadrupole mass filter. The high transmission of the new spectrometer improves the SIMS analytical sensitivity of the microprobe better than a hundredfold, overcoming most of the previous imaging limitations resulting from low count statistics.

Imaging of Al-Li-Cu alloys with a Scanning Ion Microprobe

1990 ◽  
Vol 48 (2) ◽  
pp. 314-315
Author(s):  
K.K. Soni ◽  
D.B. Williams ◽  
J.M. Chabala ◽  
R. Levi-Setti ◽  
D.E. Newbury
Keyword(s):  
Mass Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Equilibrium Phase ◽  
Icosahedral Symmetry ◽  
Ion Microprobe ◽  
X Ray ◽  
Cu Alloys ◽  
Two Phases ◽  
The University ◽  
Secondary Ion

In contrast to the inability of x-ray microanalysis to detect Li, secondary ion mass spectrometry (SIMS) generates a very strong Li+ signal. The latter’s potential was recently exploited by Williams et al. in the study of binary Al-Li alloys. The present study of Al-Li-Cu was done using the high resolution scanning ion microprobe (SIM) at the University of Chicago (UC). The UC SIM employs a 40 keV, ∼70 nm diameter Ga+ probe extracted from a liquid Ga source, which is scanned over areas smaller than 160×160 μm2 using a 512×512 raster. During this experiment, the sample was held at 2 × 10-8 torr.In the Al-Li-Cu system, two phases of major importance are T1 and T2, with nominal compositions of Al2LiCu and Al6Li3Cu respectively. In commercial alloys, T1 develops a plate-like structure with a thickness <∼2 nm and is therefore inaccessible to conventional microanalytical techniques. T2 is the equilibrium phase with apparent icosahedral symmetry and its presence is undesirable in industrial alloys.

Sign in / Sign up

Export Citation Format

Share Document