Sodium chromic phosphate

Chromic Orthophosphates.—Violet chromic phosphate, CrPO. BHgO, is produced as a lavender amorphous precipitate when cold solutions of equal weights of chrome alum and ordinary sodium phosphate are mixed ... 

This is the final neutralizing rinse after the pre-treatment to obtain a better corrosion resistance. The phosphated surfaces are treated with chromic acid-based or acidified sodium dichromate solutions which are not affected by moisture and thus protect the phosphate coating. 

Chromate conversion coatings for aluminum are carried out in acidic solutions. These solutions usually contain one chromium salt, such as sodium chromate or chromic acid and a strong oxidizing agent such as hydrofluoric acid or nitric acid. The final film usually contains both products and reactants and water of hydration. Chromate films are formed by the chemical reaction of hexavalent chromium with a metal surface in the presence of accelerators such as cyanides, acetates, formates, sulfates, chlorides, fluorides, nitrates, phosphates, and sulfamates. 

In the present work, steel surfaces polished, phosphated and painted are studied using AC Impedance technique In order to evaluate the protection efficiency of a commercial phosphatlng solution. The AC Impedance behavior of painted metal has been correlated with the Immersion time In the phosphatlng solution and with the desirability of a phospho-chromic rinse (18-23). A comparison of the Impedance behavior of two different types of commercial paints Is made for various durations of Immersion In sodium chloride solution at room temperature, and also for various temperatures at a given duration of Immersion. 

The electrical conductivities of soln. of a great many compounds in liquid hydrogen halides have been measured by E. H. Archibald and D. McIntosh. The conductivity is raised considerably by phosphoryl chloride. Sodium sodium sulphide, borate, phosphate, nitrate, thiosulphate, and arsenate chromic anhydride potassium nitrate, hydroxide, chromate, sulphide, bisulphate, and ferro- and ferri- cyanide ammonium fluoride and carbonate j rubidium and caesium chloride magnesium sulphate calcium fluoride ... 

Chromous Orthophosphate, CrgfPO lj.HaO, is the abundant blue gelatinous precipitate obtained w hen ordinary sodium phosphate is added to chromous chloride solution. It is readily soluble in acids, and on exposure to air rapidly changes to the green chromic salt. It does not form double salts with ammonium phosphate. ... 

Hydroxyethyl cellulose has good tolerance for dissolved electrolytes, although it may be salted out of solution when mixed with certain salt solutions. For example, the following salt solutions will precipitate a 10% w/v solution of Cellosize WP-09 and a 2% w/v solution of Cellosize WP-4400 sodium carbonate 50% and saturated solutions of aluminum sulfate ammonium sulfate chromic sulfate disodium phosphate magnesium sulfate potassium ferrocyanide sodium sulfate sodium sulfite sodium thiosulfate and zinc sulfate. 

Nugatory attempts to render the metal active by the addition of cupric chloride, sodium sulphite, alcohol, ferrous chloride, ferric chloride, colloidal platinum, chromic acid, potassium nitrite prolonged contact with metallic platinum variation of temp, between 0 and 50° previous treatment of the metal with chromic acid or potassium permanganate fusion with potassium nitrate heating on charcoal with sodium phosphate to give the metal a phosphorus content melting in the electric oven in an atm. of coal-gas using the metal as anode have all been made. 

Polyethylene catheters were surface primed either with chromic acid solution or with oxygen plasma treatment, then dipped into a 0.6 % chitosan solution in 1 % acetic acid. After drying, the catheters were exposed to ammonia and then soaked in a pH 7.0 phosphate buffer containing 1 % heparin. About 40 yg of chitosan were deposited per square cm. The heparinization procedure added 2-3 units of heparin per square cm. This heparin can be removed by soaking in 25 % sodium chloride, however, if the heparinization is performed in the presence of sodium cyanoborohydride, the brine removes only a minor part of heparin. Negligible amounts of the coating were removed by blood at 37°C after 24 hr contact. 

This stated that compounds which crystallise in the same form (i.e. are isomorphous) are similar in atomic composition, and he quoted as examples the sodium phosphates and arsenates, in which an arsenic atom takes the place of a phosphorus atom. Mitscherlich used the fact that potassium selenate was isomorphous with potassium sulphate to deduce the formula of potassium selenate, and hence determine the atomic weight of selenium. Berzelius used the isomorphism of the sulphates and the chromates as evidence that the formula of anhydrous chromic acid was CrOj. He suggested that the lower oxide of chromium had a formula of Q2O3, and since this was isomorphous with the oxides of iron and aluminium, he was able to propose correct formulae for these compounds. 

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