Interface Reactions in Bilayers of Aluminum and Nickel-Chromium Alloy

1991 ◽  
Vol 238 ◽  
Author(s):  
S. M. Heald ◽  
Zhengquan Tan ◽  
J. K. D. Jayanetti
Keyword(s):  
Interface Reaction ◽  
Pure Metal ◽  
Initial Reaction ◽  
Chromium Alloy ◽  
Rich Region ◽  
Interface Reactions ◽  
Nickel Chromium ◽  
Chromium Alloys ◽  
Glancing Angle ◽  
Bcc Structure

ABSTRACTGlancing angle EXAFS and x-ray reflectivity are used to study the interface reaction between nickel-chromium alloys and aluminum. The two metals are found to react independently with Al, with the first reactions taking place at temperatures similar to those found for the pure metals. This means that Ni reacts first with Al to form NiAl3, leaving behind a Cr-rich region at the interface. In this Cr-rich region some of the Cr transforms to the bcc structure from the fcc form of the alloy. At higher temperatures Cr reacts to form CrAl7, and there is no evidence for ternary compound formation. Samples were also prepared with a controlled O contamination at the interface, and it inhibits the reaction much the same as for the pure metal cases. The Ni reaction is not identical to the pure sample case, since the presence of Cr slows down the reaction, and inhibits the initial reaction in the as-prepared bilayers.

scholarly journals Effect of recasting on the elastic modulus of metal-ceramic systems from nickel-chromium and cobalt-chromium alloys

2007 ◽  
Vol 64 (7) ◽  
pp. 469-473 ◽  
Author(s):  
Nemanja Mirkovic
Keyword(s):  
Elastic Modulus ◽  
Testing Machine ◽  
Fracture Load ◽  
Bending Test ◽  
Chromium Alloy ◽  
Cobalt Chromium ◽  
Nickel Chromium ◽  
Ceramic Samples ◽  
Chromium Alloys ◽  
Metal Ceramic

Background/Aim. Elastic modulus of metal-ceramic systems determines their flexural strength and prevents damages on ceramics during mastication. Recycling of basic alloys is often a clinical practice, despite the possible effects on the quality of the future metal-ceramic dentures. This research was done to establish recasting effects of nickel-chromium and cobalt-chromium alloys on the elastic modulus of metalceramic systems in making fixed partial dentures. Methods. The research was performed as an experimental study. Six metal-ceramic samples of nickel-chromium alloy (Wiron 99) and cobalt-chromium alloy (Wirobond C) were made. Alloy residues were recycled through twelve casting generations with the addition of 50% of new alloy on the occasion of every recasting. Three- point bending test was used to determine elastic modulus, recommended by the standard ISO 9693:1999. Fracture load for damaging ceramic layer was recorded on the universal testing machine (Zwick, type 1464), with the speed of 0,05 mm/min. Results. The results of this research revealed significant differences between elasticity modules of metal-ceramic samples in every examined recycle generation. Recasting had negative effect on the elastic modulus of the examined alloys. This research showed the slight linear reduction of elastic modulus up to the 6th generation of recycling. After the 6th recycling there was a sudden fall of elastic modulus. Conclusion. Recasting of nickelchromium and cobalt-chromium alloys is not recommended because of the reduced elastic modulus of these alloys. Instead of reusing previously recasted alloys, the alloy residues should be returned to the manufacturer. .

Glancing angle x-ray study of the effect of oxygen on interface reactions in Al/Ni bilayers

1991 ◽  
Vol 6 (5) ◽  
pp. 935-942 ◽  
Author(s):  
S.M. Heald ◽  
E.V. Barrera
Keyword(s):  
Grain Boundary ◽  
Boundary Diffusion ◽  
Bulk Diffusion ◽  
Diffusion Path ◽  
Initial Reaction ◽  
X Ray ◽  
Interface Reactions ◽  
Glancing Angle ◽  
Effect Of Oxygen ◽  
Oxygen Impurities

Glancing angle x-ray reflectivity and EXAFS measurements have been made on a series of UHV prepared Al/Ni bilayers with varying amounts of oxygen impurities. These samples show an intrinsic reacted region prior to annealing, and for clean samples further reaction occurs at 250 °C. Oxygen is found to influence strongly the course of the reaction with an effect which depends on its location. A few percent O impurity within the Al film strongly suppresses the grain boundary diffusion path, which allows the growth of a smooth NiAl3 layer. Interfacial O exposures of 60 and 600 Langmuir both inhibit the initial reaction and raise the temperature at which further reaction occurs to as much as 300 °C with an effect which depends on exposure. The thickness of the intrinsic reaction zone is about 60 Å for clean samples, and is nearly eliminated for contaminated interfaces. The results indicate that surface/interface, grain boundary, and bulk diffusion all play important roles in the formation of these interfaces, and that each of these is influenced by O impurities.

scholarly journals EDX analyisis of metal-ceramic interfaces of recasted nickel-chromium dental alloys

2018 ◽  
Vol 72 (3) ◽  
pp. 149-156
Author(s):  
Vladimir Stefanovic ◽  
Zoran Lazic ◽  
Nemanja Mirkovic ◽  
Ervin Taso ◽  
Nenad Simeunovic ◽  
...  
Keyword(s):  
Intermediate Phase ◽  
Nickel Concentration ◽  
Detailed Knowledge ◽  
Chromium Alloy ◽  
Dental Alloys ◽  
Nickel Chromium ◽  
Ceramic Samples ◽  
Chromium Alloys ◽  
Metal Ceramic ◽  
Ceramic Interfaces

This research was performed to establish recasting effects of nickel-chromium dental alloys on the composition of their metal-ceramic interface in making fixed partial dentures. The metal-ceramic interface determines denture functional integrity and prevents damages on ceramics during mastication. Recycling of nickel-chromium alloys is often a practice, without detailed knowledge about possible effects on the composition of the metal-ceramic interface. Investigation of metal-ceramic samples is intended to show if base metal alloys for metal-ceramics are successfully recycled without any composition change in the metal-ceramic interface. The research was performed as an experimental study in which six metal-ceramic samples of nickel-chromium alloy ?Wiron 99? (Bego, Germany) were made. Alloy residues were recycled through twelve casting generations with the addition of 50 wt% of the new alloy on the occasion of every recasting. EDX analysis was performed by using the ?Inca X Sight? apparatus (Oxford Instruments, UK) and a SEM device JSM 6460 LV (JEOL, Japan). This appliance was used in conjunction with the PC software for quantification of chemical elements in order to determine the composition of metal-ceramic interfaces. Results of this research revealed significant differences between compositions of metal-ceramic interfaces in every examined recycle generation. Recasting had a negative effect on alloy components, which concentration is decreasing in the metal-ceramic junction zone. The concentration of cerium in the intermediate phase decreased the most, followed by concentrations of niobium, molybdenum, nickel and chromium. Results showed a permanent reduction of metal components up to the 12th generation of recycling. Cerium concentration (wt%) decreased from 28 to 16.26 %, nickel concentration from 3.31 to 1.82 % and chromium concentration from 2.95 to 2.03 %. Similarly, the molybdenum content decreased from 8.71to 4.68 wt%, while that of niobium from 9.82 to 3.97 wt%. Therefore, recasting of nickel-chromium alloys is not recommended because of changed composition of the metal-ceramic interface of these alloys.

scholarly journals Effect of recasting on the thickness of metal-ceramic interface of nickel-chromium and cobalt-chromium alloys

2008 ◽  
Vol 65 (5) ◽  
pp. 365-369 ◽  
Author(s):  
Nemanja Mirkovic ◽  
Miroslav Draganjac ◽  
Dragoslav Stamenkovic ◽  
Ljubisa Ristic
Keyword(s):  
Sem Analysis ◽  
Chromium Alloy ◽  
Interface Thickness ◽  
Cobalt Chromium ◽  
X Ray ◽  
Nickel Chromium ◽  
Ceramic Samples ◽  
Chromium Alloys ◽  
Metal Ceramic ◽  
Negative Effect

Introduction/Aim. This research was done to establish recasting effects of nickel-chromium and cobalt-chromium alloys on the thickness of their metal-ceramic interface in making fixed partial dentures. Metal-ceramic interface determines their functional integrity and prevents damages on ceramics during mastication. Investigation of metal-ceramic samples is supposed to show if base metal alloys for metalceramics are successfully recycled without any risk of reduction of metal-ceramic interface thickness. Methods. The research was performed as an experimental study. Per six metal-ceramic samples of nickel-chromium alloy (Wiron99) and cobalt-chromium alloy (Wirobond C) were made each. Alloy residues were recycled through twelve casting generations with the addition of 50% of new alloy on the occasion of every recasting. Analysis Energy Dispersive X-ray (EDX) (Oxford Instruments) and Scanning Electon Microscop (SEM) analysis (JEOL) were used to determine thickness of metal-ceramic interface together with PC Software for quantification of visual information's (KVI POPOVAC). Results. Results of this research introduced significant differences between thickness of metal-ceramic interface in every examined recycle generation. Recasting had negative effect on thickness of metal-ceramic interface of the examined alloys. This research showed almost linear reduction of elastic modulus up to the 12th generation of recycling. Conclusion. Recasting of nickel-chromium and cobaltchromium alloys is not recommended because of reduced thickness of metal-ceramic interface of these alloys. Instead of recycling, the alloy residues should be returned to the manufacturers.

Study of Frictional Properties of AMS Nickel-Chromium Alloys

2016 ◽  
Vol 674 ◽  
pp. 244-249 ◽  
Author(s):  
Tomasz Trzepieciński ◽  
Andrzej Trytek ◽  
Hirpa G. Lemu
Keyword(s):  
Friction Coefficient ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Aerospace Industry ◽  
Rolling Direction ◽  
Normal Pressure ◽  
Chromium Alloy ◽  
Nickel Chromium ◽  
Chromium Alloys

The research reported in this article has considered the frictional characteristics of three kinds of AMS nickel-chromium alloys that are commonly used in aerospace industry. These are alloys with additions of titanium and aluminum AMS5542, nickel-chromium alloy AMS5596, and non-magnetic, corrosion and oxidation resistant, nickel-chromium alloy AMS5599. To determine the friction coefficient two tribological tests, a strip drawing test and a pin-on-disc tribometer have been conducted. Three different friction conditions were considered, dry friction, lubrication conditions using two grades of oils used in sheet metal forming of AMS alloys. The experimental results have ascertained several relationships showing the effect of sheet metal surface roughness, lubricant conditions and sheet orientation on the value of friction coefficient in sheet metal forming processes. Different levels of normal pressure were also used in friction tests. The results further showed that the surface topography and sample orientation in the rolling direction of the sheet are significant factors that influence the friction coefficient. It has been observed that the tested AMS alloys, selected from aerospace industry applications, exhibit anisotropic resistance to the friction corresponding to the measured orientation in relation to the rolling direction of the sheet.

scholarly journals Mechanical properties of metal-ceramic systems from nickel-chromium and cobalt-chromium alloys

2007 ◽  
Vol 64 (4) ◽  
pp. 241-245 ◽  
Author(s):  
Nemanja Mirkovic
Keyword(s):  
Elastic Modulus ◽  
Bond Strength ◽  
Testing Machine ◽  
Bending Test ◽  
Chromium Alloy ◽  
Cobalt Chromium ◽  
Nickel Chromium ◽  
Chromium Alloys ◽  
Ceramic Bond ◽  
Metal Ceramic

Background/Aim. Metal-ceramic bond strength and alloys' elastic modulus clearly determine the potential of alloy application, because the ceramic integrity during mastication depends on these two characteristics. The aim of this study was to evaluate metal-ceramic bond strength and elastic modulus of cobalt-chromium alloys in making porcelainfused- to-metal restorations, regarding the application of the most frequent nickel-chromium alloy. Methods. The research was performed as an experimental study. Six metalceramic samples were made from nickel-chromium alloy (Wiron 99) and cobalt-chromium alloy (Wirobond C), according to the manufactures manuals and instructions from ISO 9693: 1996. Three-point bending test was performed up to the ceramic fracture. The fracture load was measured on an universal testing machine (Zwick, type 1464), with cross-head speed of 0,05mm/min. Results. The results of this study confirmed the significant differences between the metal-ceramic bond strength (p < 0.01) and elastic modulus (p < 0.001) of nickel-chromium and cobalt-chromium alloys, where cobalt-chromium alloys showed higher values for both tested parameters. Conclusion. Cobalt-chromium metal-ceramic alloys can successfully replace nickel-chromium alloys, especially for fabrication of long-span metal-ceramic bridges due to the great flexural strength.

HREM observation of NiO growth on submicron spheres of pure nickel

1989 ◽  
Vol 47 ◽  
pp. 548-549
Author(s):  
C.M. Teng ◽  
T.F. Kelly ◽  
J.P. Zhang ◽  
H.M. Lin ◽  
Y.W. Kim
Keyword(s):  
Nickel Oxide ◽  
Grain Boundaries ◽  
Pure Nickel ◽  
Submicron Particles ◽  
Crystal Formation ◽  
Nickel Wire ◽  
Liquid Droplets ◽  
Oxide Interface ◽  
Nickel Chromium ◽  
Chromium Alloys

Spherical submicron particles of materials produced by electrohydrodynamic (EHD) atomization have been used to study a variety of materials processes including nucleation of alternative crystallization phases in iron-nickel and nickel-chromium alloys, amorphous solidification in submicron droplets of pure metals, and quasi-crystal formation in nickel-chromium alloys. Some experiments on pure nickel, nickel oxide single crystals, the nickel/nickel(II) oxide interface, and grain boundaries in nickel monoxide have been performed by STEM. For these latter studies, HREM is the most direct approach to obtain particle crystal structures at the atomic level. Grain boundaries in nickel oxide have also been investigated by HREM. In this paper, we present preliminary results of HREM observations of NiO growth on submicron spheres of pure nickel.Small particles of pure nickel were prepared by EHD atomization. For the study of pure nickel, 0.5 mm diameter pure nickel wire (99.9975%) is sprayed directly in the EHD process. The liquid droplets solidify in free-flight through a vacuum chamber operated at about 10-7 torr.

INCONEL ALLOY X-750

Alloy Digest ◽  
1966 ◽  
Vol 15 (7) ◽  
Keyword(s):  
Gas Turbines ◽  
Rupture Strength ◽  
Low Cost ◽  
High Strength ◽  
Heat Treating ◽  
Chromium Alloy ◽  
Cryogenic Temperatures ◽  
Inconel Alloy ◽  
Nickel Chromium ◽  
Corrosion And Oxidation

Abstract INCONEL alloy X-750 is an age-hardenable, nickel-chromium alloy used for its corrosion and oxidation resistance and high creep rupture strength at temperature up to 1500 F. It also has excellent properties at cryogenic temperatures. It was originally developed for use in gas turbines, but because of its low cost, high strength and weldability it has become the standards choice for a wide variety of applications. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep and fatigue. It also includes information on forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-115. Producer or source: Huntington Alloy Products Division, An INCO Company.

INCONEL ALLOY 671

Alloy Digest ◽  
1972 ◽  
Vol 21 (10) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Surface Treatment ◽  
Heat Treating ◽  
High Temperature Corrosion ◽  
Chromium Alloy ◽  
Inconel Alloy ◽  
Nickel Chromium ◽  
Temperature Performance

Abstract INCONEL ALLOY 671 is a nickel-chromium alloy having excellent resistance to high-temperature corrosion. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-180. Producer or source: Huntington Alloy Products Division, An INCO Company.

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