scholarly journals Sodium Dichromate

2020 ◽  
Author(s):  
Keyword(s):  
Sodium Dichromate

Physical, Chemical, and Crystallographic Characterization of Anodic Coatings on High Strength Aluminum Base Alloys

1976 ◽  
Vol 34 ◽  
pp. 636-637
Author(s):  
R. E. Herfert ◽  
N. T. McDevitt
Keyword(s):  
Sulfuric Acid ◽  
Salt Spray ◽  
High Strength ◽  
Environmental Stability ◽  
Anodic Films ◽  
Sodium Dichromate ◽  
Corrosion Resistant ◽  
Aerospace Applications ◽  
Bond Strengths ◽  
Adhesive Bonded Joints

Durability of adhesive bonded joints in moisture and salt spray environments is essential to USAF aircraft. Structural bonding technology for aerospace applications has depended for many years on the preparation of aluminum surfaces by a sulfuric acid/sodium dichromate (FPL etch) treatment. Recently, specific thin film anodizing techniques, phosphoric acid, and chromic acid anodizing have been developed which not only provide good initial bond strengths but vastly improved environmental durability. These thin anodic films are in contrast to the commonly used thick anodic films such as the sulfuric acid or "hard" sulfuric acid anodic films which are highly corrosion resistant in themselves, but which do not provide good initial bond strengths, particularly in low temperature peel.The objective of this study was to determine the characteristics of anodic films on aluminum alloys that make them corrosion resistant. The chemical composition, physical morphology and structure, and mechanical properties of the thin oxide films were to be defined and correlated with the environmental stability of these surfaces in humidity and salt spray. It is anticipated that anodic film characteristics and corrosion resistance will vary with the anodizing processing conditions.

THE EFFECT OF ELECTROLYTE TEMPERATURE AND SEALING SOLUTION IN ANODIZING OPERATION ON HARDNESS AND WEAR BEHAVIOR OF 7075 -T6 ALUMINUM ALLOY

2019 ◽  
Vol 26 (02) ◽  
pp. 1850143
Author(s):  
SAEED NIYAZBAKHSH ◽  
KAMRAN AMINI ◽  
FARHAD GHARAVI
Keyword(s):  
Weight Loss ◽  
Wear Resistance ◽  
Aluminum Alloy ◽  
Wear Behavior ◽  
Anodic Oxide ◽  
Boiling Water ◽  
Electrolyte Temperature ◽  
Oxide Coatings ◽  
Sodium Dichromate ◽  
Pin On Disk

Anodic oxide coatings are applied on aluminum alloys in order to improve corrosion resistance and to increase hardness and wear resistance. In the current study, a hard anodic coating was applied on AA7075-T6 aluminum alloy. To survey the anodizing temperature (electrolyte temperature) effect, three temperatures, namely, [Formula: see text]C, 0∘C and 5∘C were chosen and the samples were sealed in boiling water and sodium dichromate to study the role of sealing. For measuring the oxide coatings porosity and hardness and also for comparing the samples’ wear resistance field-emission scanning electron microscopy (FESEM), microhardness test and pin-on-disk method were utilized, respectively. The results showed that by increasing the anodizing temperature, hardness and consequently wear resistance decreased so that hardness and weight loss in the samples with no sealing decreased from 460[Formula: see text]HV and 0.61[Formula: see text]mg at [Formula: see text]C to 405 and 358[Formula: see text]HV and 1.05 and 1.12[Formula: see text]mg at 0∘C and 5∘C, respectively, which is due to the porosity increment by increasing the anodizing temperature. Also, sealing in boiling water and dichromate contributed to soft phases and coating hydration, which resulted in a decrease in hardness and wear resistance. Hardness and weight loss in the coated samples at [Formula: see text]C decreased from 460[Formula: see text]HV and 0.61[Formula: see text]mg in the samples with no sealing to 435 and 417[Formula: see text]HV and 0.72 and 0.83[Formula: see text]mg in the samples sealed in boiling water and dichromate, respectively.

Shaken Not Stirred: Oxidation of Alcohols with Sodium Dichromate.

ChemInform ◽  
2006 ◽  
Vol 37 (17) ◽  
Author(s):  
Ji-Dong Lou ◽  
Chun-Ling Gao ◽  
Yi-Chun Ma ◽  
Li-Hong Huang ◽  
Li Li
Keyword(s):  
Sodium Dichromate ◽  
Oxidation Of Alcohols

Chemistry of the Podocarpaceae. XXXIV. Some oxidation products of (13R)-Labda-8(17),14-dien-13-ol (Manool)

1971 ◽  
Vol 24 (11) ◽  
pp. 2365 ◽  
Author(s):  
RC Cambie ◽  
KN Joblin ◽  
AF Preston
Keyword(s):  
Nucleophilic Substitution ◽  
Potassium Permanganate ◽  
Hydroxy Acid ◽  
Methyl Ketone ◽  
Major Product ◽  
Oxidation Products ◽  
Lithium Aluminium Hydride ◽  
Methyl Ketones ◽  
Sodium Dichromate ◽  
Lithium Aluminium

Some products from the oxidation of manool (3) are examined. Potassium permanganate gives, inter alia, the hitherto unreported compound (16) while sodium dichromate gives the methyl ketone (5) and, as the major product, a mixture of (Z)- and (E)-α,β-unsaturated aldehydes (21). Hypoiodite oxidation of the methyl ketone (5) gives the α-hydroxy acid (26) in addition to the expected acid (6). Products of nucleophilic substitution have also been obtained from the hypoiodite oxidation of the methyl ketones (9) and (37). Peracid oxidation of the methyl ketone (5) gives the epoxy acetate (41) which, on reduction with lithium aluminium hydride, affords the diol (7), from which the odoriferous oxide (30) can be prepared. Oxidations leading to formation of the dione (10) are investigated.

scholarly journals MARINE EXPOSURE TESTS OF COCONUT TIMBER

CORD ◽  
1987 ◽  
Vol 3 (01) ◽  
pp. 34
Author(s):  
R. N. Palomar
Keyword(s):  
Sea Water ◽  
Coal Tar ◽  
Untreated Wood ◽  
Double Diffusion ◽  
Marine Structures ◽  
Sodium Dichromate ◽  
Diffusion Treatment ◽  
Pressure Method ◽  
Copper Arsenate ◽  
Hard Samples

Marine exposure tests of sawn coconut lumber were carried out for three years to determine the resistance, of treated coconut timber to marine borers.   The test panels measuzing 50 mm x 100 mm x 450 mm, were installed in sea water between October, 1981 and September, 1984. Results showed three promising treatments. These were the vacuum/pressure method using chromated copper arsenate, the modifted double diffusion treatment employing mixture of copper adphate, sodium dichromate and arsenic pentoxide, and the hot and cold bath treatment with coal tar creosote. The specimens treated by these preservative systems showed trace or slight sur­face infestation while the untreated wood panels indicated from deep and extensive infestation to failure due to attack of marine borers.   The perfomance of the treated medium density specimens appeared to be inferior than the hard samples indicating that only the latter materials should be used for marine structures.

Sign in / Sign up

Export Citation Format

Share Document