Corrosion-resistant alloys in chloride solutions: materials for surgical implants

1966 ◽  
Vol 294 (1439) ◽  
pp. 486-510 ◽  
Keyword(s):  
Current Density ◽  
Stainless Steels ◽  
Chloride Concentration ◽  
Body Fluids ◽  
Physiological Solution ◽  
The Body ◽  
Chloride Solutions ◽  
Corrosion Resistant ◽  
Surgical Implants ◽  
Current Densities

The behaviour of a number of corrosion-resistant alloys in chloride solutions, in Hanks’s physiological solution (simulating the extracellular body fluids) and as surgical implants has been investigated by electrochemical means, namely potential-time curves for isolated specimens, potential-current density curves for anodes, and current density-time curves for anodes maintained electronically at constant potential. Microscopical observation of pitting attack has also been made. Alloys based on iron (e. g. stainless steels), nickel (e. g. Inconel, Nimonic 75, etc.), cobalt (Vitallium), titanium and tantalum exposed to chloride solutions all show a range of potential in which they are passive, and, at sufficiently high chloride concentration and sufficiently positive potential, breakdown giving rise to pits that are electrobrightened. This general phenomenon occurs, in 0·17M sodium chloride solution, at 0·2 to 0·5 V (normal hydrogen scale) for stainless steels, ca . 0·9 V for the cobalt·based alloys, and ca . 20 to 30 V for certain titanium alloys and tantalum. In the passive range, all the alloys show anode current densities in the range 10 -6 to below 10 -9 A/cm 2 , the smaller current densities given by the most passive alloys (e. g. titanium-5 % niobium) often tending to decrease yet further with passage of time. We conclude that stainless steels (even of the higher chromium-nickel quality) and nickel alloys are unlikely to resist all breakdown by pitting when exposed to the body fluids (or other media containing chloride) indefinitely; that the cobalt-based alloys may well withstand such exposure for very long times; and that titanium and (especially) some of its alloys should withstand such exposure for an indefinite period. The (extremely slow) passage of cobalt and titanium into the environment is caused by passage of cations through their passivating oxide films, without breakdown.

Surgical Diathermy

2011 ◽  
Author(s):  
Patrick Magee ◽  
Mark Tooley
Keyword(s):  
Current Density ◽  
The Body ◽  
Heating Power ◽  
Driving Voltage ◽  
Physiological Effects ◽  
Heating Effect ◽  
Surgical Tool ◽  
Average Current ◽  
Current Densities ◽  
A Current

As discussed in Chapter 4, when a voltage is applied across a conductor, a current will flow. If the voltage is applied across the body via suitable electrodes the body becomes part of the circuit and a current will also flow, the magnitude depending on the properties of the tissues in its path, particularly the resistance. This current can cause heating or other physiological effects, depending on the frequency of the driving voltage. The effects of the domestic mains current flowing through the body was discussed in Chapter 6, but different effects occur as the frequency of the voltage is increased. As the frequency goes up, the heating increases but the tissue stimulation decreases and, at frequencies above 100 kHz (i.e. radio frequencies), the effect is entirely heating. This heating effect in the body by electric current is called diathermy, but the location, concentration and how this heat is used is dependant on the electrode design and the current concentration or current density at any point in the circuit. For a certain applied voltage, the average current throughout the circuit will be the same. The current density is the current per unit area, and so if the material in which the current passes is smaller, the heating effect increases. The resistance of the material is proportional to its size, so as the material becomes smaller then its resistance gets larger. The heating power is the product of the current squared and the resistance (power = I2 × R). Surgical diathermy (or electrosurgery) is where either one or both of the electrodes are very small, and it is used to cut and coagulate tissue. The smaller electrode can be made into a pointed surgical tool and localised heating will occur at the tip of the instrument. The smaller and more pointed the instrument is, the greater the current density will be at the tip. This electrode is classified as the active or live one. The current densities around this electrode can be as much as 10 A cm−2, and the total heating power typically around 200 W.

EFFECT OF GELATIN ON THE CHANGES IN INITIAL CATHODE POLARIZATION DURING ELECTRODEPOSITION OF COPPER

1954 ◽  
Vol 32 (6) ◽  
pp. 581-590 ◽  
Author(s):  
B. I. Parsons ◽  
C. A. Winkler
Keyword(s):  
Steady State ◽  
Current Density ◽  
Copper Sulphate ◽  
Chloride Concentration ◽  
High Current ◽  
Concentration Increase ◽  
Addition Agent ◽  
Cathode Polarization ◽  
Current Densities ◽  
Gelatin Concentration

In the absence of addition agent, the cathode polarization during initial electrolysis of copper from a solution of acid copper sulphate rose almost instantaneously from zero to approximately the steady state polarization. When gelatin was present in the electrolyte, the polarization generally increased to a maximum, Pmax, (in time tmax) then decreased to a minimum, Pmin, (in-time tmin) beyond which it increased to the steady state value, Ps. Generally, Pmax increased to a steady value with an increase in the time, T0, the electrode was in contact with the electrolyte before electrolysis was begun. At low, moderate, and high current densities respectively, tmax increased continuously, passed through a maximum, and decreased continuously with T0.The behavior of tmin approximately paralleled that of tmax. The polarization was linear in the logarithm of the current density; tmax and tmin decreased with increase in current density. The polarization values increased and tmax decreased, with increase in gelatin concentration. Increase of temperature had approximately the same effect as decrease in current density. With both chloride and gelatin present, Pmax was practically independent of T0 and chloride concentration, while Pmin and Ps showed minimum values at about 2 mgm./l. chloride.

scholarly journals The Osmotic Relations of the Earthworm

1949 ◽  
Vol 26 (1) ◽  
pp. 46-56
Author(s):  
J. A. RAMSAY
Keyword(s):  
Osmotic Pressure ◽  
Fresh Water ◽  
Chloride Concentration ◽  
Body Fluids ◽  
The Body ◽  
Coelomic Fluid ◽  
Fluid Blood

1. Osmotic pressure and chloride concentration have been determined for the coelomic fluid, blood and urine of earthworms kept in various saline media. 2. About 50% of the osmotic pressure of the coelomic fluid and of the blood can be accounted for as chloride. The blood is very slightly hypotonic to the coelomic fluid. 3. As the concentration of the medium is increased the osmotic pressure of the body fluids also increases and is always greater than that of the medium; the chloride increases proportionately, but is less than that of the medium when the latter exceeds 0.35% NaCl. 4. The urine is always strongly hypotonic to the body fluids except possibly in the most concentrated media (over 1.0% NaCl). 5. The osmotic relations of the earthworm are such as are characteristic of fresh-water animals generally.

Facet Topography and Dislocation Structure as a Possible Source for Electrical Heterogeneity in [001] TILT Bicrystals of YBa2Cu3O7-δ

1996 ◽  
Vol 54 ◽  
pp. 338-339
Author(s):  
I-Fei Tsu ◽  
D.L. Kaiser ◽  
S.E. Babcock
Keyword(s):  
Grain Boundary ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Electromagnetic Properties ◽  
Length Scale ◽  
Density Values ◽  
Current Densities ◽  
Applied Fields ◽  
A Current

A current theme in the study of the critical current density behavior of YBa2Cu3O7-δ (YBCO) grain boundaries is that their electromagnetic properties are heterogeneous on various length scales ranging from 10s of microns to ˜ 1 Å. Recently, combined electromagnetic and TEM studies on four flux-grown bicrystals have demonstrated a direct correlation between the length scale of the boundaries’ saw-tooth facet configurations and the apparent length scale of the electrical heterogeneity. In that work, enhanced critical current densities are observed at applied fields where the facet period is commensurate with the spacing of the Abrikosov flux vortices which must be pinned if higher critical current density values are recorded. To understand the microstructural origin of the flux pinning, the grain boundary topography and grain boundary dislocation (GBD) network structure of [001] tilt YBCO bicrystals were studied by TEM and HRTEM.

Electron-beam damage of oxides at high current densities

1989 ◽  
Vol 47 ◽  
pp. 634-635
Author(s):  
M. R. McCartney ◽  
J. K. Weiss ◽  
David J. Smith
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Current Density ◽  
Transition Metal Oxides ◽  
Time Resolved ◽  
Rapid Acquisition ◽  
Resolution Electron ◽  
Current Densities ◽  
Electron Stimulated Desorption ◽  
Channel Analyzer

It is well-known that electron-beam irradiation within the electron microscope can induce a variety of surface reactions. In the particular case of maximally-valent transition-metal oxides (TMO), which are susceptible to electron-stimulated desorption (ESD) of oxygen, it is apparent that the final reduced product depends, amongst other things, upon the ionicity of the original oxide, the energy and current density of the incident electrons, and the residual microscope vacuum. For example, when TMO are irradiated in a high-resolution electron microscope (HREM) at current densities of 5-50 A/cm2, epitaxial layers of the monoxide phase are found. In contrast, when these oxides are exposed to the extreme current density probe of an EM equipped with a field emission gun (FEG), the irradiated area has been reported to develop either holes or regions almost completely depleted of oxygen. ’ In this paper, we describe the responses of three TMO (WO3, V2O5 and TiO2) when irradiated by the focussed probe of a Philips 400ST FEG TEM, also equipped with a Gatan 666 Parallel Electron Energy Loss Spectrometer (P-EELS). The multi-channel analyzer of the spectrometer was modified to take advantage of the extremely rapid acquisition capabilities of the P-EELS to obtain time-resolved spectra of the oxides during the irradiation period. After irradiation, the specimens were immediately removed to a JEM-4000EX HREM for imaging of the damaged regions.

IMPLEMENTATION OF FATWA ULAMA COUNCIL ACEH CONCERNING MAINTAINING FARDHU KIFAYAH FOR THE MUSLIM’S CORPSE INFECTED BY COVID 19 IN BANDA ACEH

2020 ◽  
Author(s):  
Andri Nirwana
Keyword(s):  
Health Workers ◽  
Descriptive Analysis ◽  
Body Fluids ◽  
The Body ◽  
Analysis Approach ◽  
Data Sets ◽  
Infected People ◽  
The Public ◽  
The People ◽  
Banda Aceh

Abstract: The phenomenon of the people who forcibly took covid's corpse 19 from the hospital to be taken care of by Fardhu Kifayah by his family and the community, became a conclusion that there was community doubt about the management of Tajhiz Mayat conducted by the hospital. Coupled with the circulation of the video of the Ruku movement 'in the corpse prayer conducted by unscrupulous parties at the Hospital, became added doubts from the public against the hospital. To solve this problem, this research uses a Descriptive Analysis approach, namely by formulating a question, namely How to arrange Covid 19's body in Banda Aceh and this question will be answered with several theories and data sets from the field. So it was concluded in a conclusion that answered the formulation of the problems mentioned. Theoretically the spread of covid 19 is very fast, the size of the virus is only 0.1 micrometer and is in body fluids, especially nasopharyngeal fluid and oropharyngeal fluids of infected people, fluids in the body of covid 19 bodies can get out through every gap of the body such as mouth, nose, eye and rectum, because it requires special techniques in its management. Fardhu kifayah to covid 19 bodies should be carried out by trained Ustad and trained health workers, so that the spread stopped. The results of this study concluded that the management of the Moslem bodies died at Zainal Abidin Hospital in Banda Aceh was in accordance with the Fatwa of the Aceh Ulama Council (MPU) and the bodies were handled by trained Ustad and health workers.

Effects of Thermal Oxidation and Subsequent Pickling on Pitting Geometry of Austentitic Stainless Steels in Chloride Solutions

2011 ◽  
Vol 53 (10) ◽  
pp. 634-638 ◽  
Author(s):  
Vesna Alar ◽  
Ivan Esih ◽  
Ivan Budic ◽  
Slavonski Brod
Keyword(s):  
Thermal Oxidation ◽  
Stainless Steels ◽  
Chloride Solutions

AISI No. 633

Alloy Digest ◽  
1981 ◽  
Vol 30 (7) ◽  
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Stainless Steels ◽  
High Strength ◽  
Heat Treating ◽  
Corrosion Resistant ◽  
Martensitic Stainless Steels ◽  
Steel Mills ◽  
Temperature Performance ◽  
Structural Applications

Abstract AISI No. 633 is a chromium-nickel-molybdenum stainless steel whose properties can be changed by heat treatment. It bridges the gap between the austenitic and martensitic stainless steels; that is, it has some of the properties of each. Its uses include high-strength structural applications, corrosion-resistant springs and knife blades. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-389. Producer or source: Stainless steel mills.

REMANIT 4439

Alloy Digest ◽  
1993 ◽  
Vol 42 (11) ◽  
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Stainless Steels ◽  
Crevice Corrosion ◽  
Heat Treating ◽  
Corrosion Resistant Steel ◽  
Resistant Steel ◽  
Low Carbon ◽  
Corrosion Resistant ◽  
Mechanical Properties And Corrosion

Abstract REMANIT 4439 is a highly corrosion resistant steel with low carbon content, an addition of nitrogen to enhance both mechanical properties and corrosion resistance, and higher molybdenum than most stainless steels to resist pitting and crevice corrosion in chloride media. This datasheet provides information on composition, physical properties, and elasticity. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-556. Producer or source: Thyssen Stahl AG.

FIRTH VICKERS F.I. (A1)

Alloy Digest ◽  
1970 ◽  
Vol 19 (4) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Stainless Steels ◽  
Heat Treating ◽  
Oil Refining ◽  
Corrosion Resistant ◽  
Temperature Performance ◽  
Plant Equipment ◽  
Corrosion Resistant Alloy

Abstract FIRTH VICKERS FI (A1) is a chromium type heat and corrosion resistant alloy steel recommended for oil refining and chemical plant equipment. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SS-236. Producer or source: Firth-Vickers Stainless Steels Ltd.

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