Corrosion Resistant Coatings for Aluminum by Hydrothermal Film Formation in Alkaline Li-Salt Solutions

1996 ◽  
Vol 432 ◽  
Author(s):  
R.G. Buchheit ◽  
M.A. Martinez ◽  
C.B. Cooper
Keyword(s):  
Transition Metal Oxides ◽  
Film Formation ◽  
Surface Film ◽  
Al Alloys ◽  
Surface Films ◽  
Salt Solutions ◽  
Corrosion Resistant ◽  
Inorganic Coatings ◽  
Coated Surfaces ◽  
Corrosion Resistant Coatings

AbstractNew methods of forming corrosion resistant inorganic coatings on Al and Al alloys are required due to environment and work safety hazards associated with the currently used Cr-based coatings technologies. In this paper we report on certain specific aspects of Al surface film formation that can be exploited to form highly corrosion resistant coatings. The aspects discussed include: formation of hydrotalcite surface films, Li2[Al2 (OH)6]2 CO3nH2O, by exposure to Li-salt solutions, elimination of unwanted Cu compounds that accumulate surface films formed on Cubearing Al alloys, and generation of high corrosion resistance by precipitating transition metal oxides on to alkaline hydrotalcite coated surfaces.

ON THE MECHANISM OF THE DISSOLUTION OF MAGNESIUM IN ACIDIC SALT SOLUTIONS: I. PHYSICAL CONTROL BY SURFACE FILMS

1953 ◽  
Vol 31 (9) ◽  
pp. 849-867 ◽  
Author(s):  
E. J. Casey ◽  
R. E. Bergeron
Keyword(s):  
Ionic Strength ◽  
Chemical Control ◽  
Corrosion Potential ◽  
Surface Film ◽  
Surface Films ◽  
Salt Solutions ◽  
Acidic Solutions ◽  
Activity Temperature ◽  
Acidic Salt ◽  
High Concentrations

A kinetic study and analysis has been made of the effects of ionic strength, acid activity, temperature, and salt type on the dissolution of magnesium in acidic salt solutions. This is an example of the simplest type of corrosion involving hydrogen evolution. The results are interpreted in terms of the effects of the various factors on the structure of a surface film which must be magnesium oxide and/or hydroxide even in acidic solutions. The importance of internal dissolutions in the film at high concentrations of attacking reagent, for this and other cases, is shown. Owing to complex formation, under certain conditions an odd case of "chemical control" of the dissolution rate in this simplest case becomes evident. Corrosion potential measurements aid in the interpretation.

Stick-Slip\Smooth Slip as a Function of Ambient Gases and Pressures Disproving Previous Models of Adhesive Wear

1988 ◽  
Vol 140 ◽  
Author(s):  
Chao Gao ◽  
Doris Kuhlmann-Wilsdorf ◽  
David D. Makel
Keyword(s):  
Film Formation ◽  
Surface Film ◽  
Substrate Surface ◽  
Electrical Contact ◽  
Copper Substrate ◽  
Ambient Atmosphere ◽  
Surface Films ◽  
Electrical Contact Resistance ◽  
Stick Slip ◽  
Average Value

AbstractFive different slip modes have been identified for bundles of copper fiberssliding on a smooth copper substrate in atmospheric air, argon and nitrogenat pressures from atmospheric to 0.01 Torr. These are stick-slip, variable sliding, intermittent stick sliding and two kinds of smooth sliding, one apparently a basic property of clean surfaces and the other due to contaminants. These forms of sliding are rather persistent once established, and they follow some trends. Specifically, low-pressure smooth sliding is coordinated with a value of the coefficient of friction (μ) near 0.15 and is seen when the surface film is exceptionally thin, while intermittent stick sliding appears to be due to “pads” on the substrate surface,and variable sliding to small particles caught in between the fibers and the copper substrate. However, the five slip modes are erratic in that under the same conditions one or another or yet a third may be observed, even though the electrical contact resistance (R) depends rather reproducibly on time, load, velocity, ambient atmosphere and pressure. That dependence indicates an equilibrium between film destruction through sliding and film formation, overwhelmingly through the presence of oxygen. In the stick-slip mode the difference between pst tic and ųK itic appears to be roughly proportional to ų 0.15, i.e. tfiee xcess of e average value of the friction coefficient above 0.15, being about 20% for ų 0.3 andvanishing near ų =0.15. During slip episodes, R spikes roughly in proportion to their magnitude. Some tentative interpretations are offered, based on the concept that ų consists of three additive components, namely due to the bulk (ųBulk), due to debris (ųDebris), and dueto scoring of surface films (ųFilm).At any rate, the conclusion that the results contradict all previous models of “adhesive” wearis inescapable.

Antibacterial activity of multilayer silver–copper surface films on catheter material

1993 ◽  
Vol 39 (9) ◽  
pp. 895-899 ◽  
Author(s):  
Robert J. C. McLean ◽  
A. A. Hussain ◽  
Michael Sayer ◽  
Peter J. Vincent ◽  
David J. Hughes ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Staphylococcus Epidermidis ◽  
Surface Film ◽  
Copper Surface ◽  
Butyl Rubber ◽  
Great Promise ◽  
Surface Films ◽  
Colony Forming Units ◽  
Coated Surfaces ◽  
And Staphylococcus Aureus

The antimicrobial activity of Ag, Cu, and layered Ag–Cu surface films, sputter-coated onto several types of catheter material, against clinical isolates of Staphylococcus epidermidis and Staphylococcus aureus was evaluated. When 20 μL of a suspension of S. epidermidis or S. aureus (2.68 × 106 colony-forming units/mL) was applied onto Ag–Cu- or Cu-coated butyl rubber, bacterial numbers were greatly reduced within 10 h, and eliminated within 24 h. In contrast, antibacterial activity was significantly less on uncoated or Ag-coated surfaces. Ag–Cu- or Cu-coated silicon rubber, polyvinylchloride, and teflon were even more effective than Ag–Cu- or Cu-coated butyl rubber. Ag–Cu layered surface films also showed antibacterial activity against Pseudomonas aeruginosa biofilm formation. Multiple metal surface film combinations show great promise in lowering the incidence of device-associated nosocomial infections.Key words: copper, silver, antimicrobial surface coating, catheter, nosocomial infections, metallic thin film combinations.

Theory of Corrosion of Alkali-Borosilicate Glass

1982 ◽  
Vol 15 ◽  
Author(s):  
David E. Clark ◽  
Larry L. Hench
Keyword(s):  
Nuclear Waste ◽  
Film Formation ◽  
Surface Film ◽  
Soda Lime ◽  
Surface Films ◽  
Glass Corrosion ◽  
Commercially Important ◽  
Corrosion Mechanisms ◽  
Exchange Network ◽  
Dissolution And Precipitation

ABSTRACTThe alkali-borosilicate (ABS) system provides the basis for a wide variety of commercially important products among which are the nuclear waste glasses. Although a large number of investigations have been undertaken in the last five years, the corrosion mechanisms of the ABS glasses have not been characterized nearly as well as for the soda-lime-silicate (NCS) glasses commonly used for containers. It is well known that the corrosion of the latter glasses involves ion exchange, network dissolution, and precipitation mechanisms resulting in the development of one of five types of surface films. In the present paper we compare the corrosion behavior to the ABS and NCS glasses and discuss our current understanding of ABS glass corrosion in terms of mechanisms, kinetics, surface film formation and thermodynamics.

scholarly journals SULFHYDRYL GROUPS IN FILMS OF EGG ALBUMIN

1941 ◽  
Vol 24 (6) ◽  
pp. 725-733 ◽  
Author(s):  
A. E. Mirsky
Keyword(s):  
Film Formation ◽  
Surface Film ◽  
Guanidine Hydrochloride ◽  
Sulfhydryl Groups ◽  
Surface Films ◽  
Fundamental Change ◽  
Egg Albumin ◽  
Sh Groups ◽  
Denatured Proteins ◽  
Albumin Molecule

1. The same number of SH groups reduces ferricyanide in surface films of egg albumin as in albumin denatured by urea, guanidine hydrochloride, Duponol, or heat, provided the ferricyanide reacts with films while they still are at the surface and with the denatured proteins while the denaturing agent (urea, heat, etc.) is present. 2. The SH groups of a suspension of egg albumin made by clumping together many surface films react with ferricyanide in the same sluggish and incomplete manner as do the groups in egg albumin denatured by concentrated urea when the urea is diluted or in albumin denatured by heat when the solution is allowed to cool off. 3. The known change in configuration of the egg albumin molecule when it forms part of a surface film explains why SH groups in the film react with ferricyanide whereas those in native egg albumin do not. In the native egg albumin molecule groups in the interior are inaccessible to certain reagents. A film is so thin that there are no inaccessible groups. 4. Because of the marked resemblance in the properties of egg albumin in surface films and of egg albumin after denaturation by the recognized denaturing agents, it may be supposed that the same fundamental change takes place in denaturation as in film formation—indeed, that film formation is one of the numerous examples of denaturation. This would mean that in general the SH groups of denatured egg albumin reduce ferricyanide and react with certain other reagents because they are no longer inaccessible to these reagents.

Surface Films on Zircaloy-2 Samples Cracked in Neutral Aqueous NaCl by Stress Corrosion

1973 ◽  
Vol 31 ◽  
pp. 46-47
Author(s):  
R.A. Ploc
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Film Thickness ◽  
Stress Corrosion ◽  
Zirconium Dioxide ◽  
Surface Film ◽  
Surface Films ◽  
Continuous Layer ◽  
Transmission Electron ◽  
Product Film

Samples of low-nickel Zircaloy-2 (material MLI-788-see(1)), when anodically polarized in neutral 5 wt% NaCl solutions, were found to be susceptible to pitting and stress corrosion cracking. The SEM revealed that pitting of stressed samples was occurring below a 2000Å thick surface film which behaved differently from normal zirconium dioxide in that it did not display interference colours. Since the initial film thickness was approximately 65Å, attempts were made to examine the product film by transmission electron microscopy to deduce composition and how the corrosion environment could penetrate the continuous layer.

Functional protective coatings of nickel-based alloys

2019 ◽  
pp. 110-114
Author(s):  
D. A. Gerashchenkov ◽  
T. I. Bobkova ◽  
A. F. Vasiliev ◽  
P. A. Kuznetsov ◽  
E. A. Samodelkin ◽  
...  
Keyword(s):  
Environmental Influence ◽  
Protective Coatings ◽  
Cold Gas Dynamic Spraying ◽  
Functional Elements ◽  
Corrosion Resistant ◽  
Gas Dynamic ◽  
Precision Alloy ◽  
Wear And Corrosion ◽  
High Level ◽  
Corrosion Resistant Coatings

A composition of a precision alloy based on the Ni–Cr–Mo system for wear and corrosion-resistant coatings by supersonic cold gas dynamic spraying has been developed. The optimum coatings composition provides high level of operational properties; its application is very promising for protection of structural and functional elements of marine equipment from aggressive environmental influence.

scholarly journals Surface Film Formation in Static-Fermented Rice Vinegar: A Case Study

Mycobiology ◽  
2019 ◽  
Vol 47 (2) ◽  
pp. 250-255
Author(s):  
Jeong Hyun Yun ◽  
Jae Ho Kim ◽  
Jang-Eun Lee
Keyword(s):  
Film Formation ◽  
Surface Film ◽  
Rice Vinegar
Sign in / Sign up

Export Citation Format

Share Document