Abstract: Baths for the chemical polishing of stainless steel surfaces which comprise a mixture of hydrochloric acid, nitric acid and phosphoric acid, a substituted or unsubstituted hydroxybenzoic acid and an amine in aqueous solution.

Abstract: Baths for the chemical polishing of stainless steel surfaces containing, in aqueous solution, a mixture of hydrochloric acid, phosphoric acid, nitric acid and of sulphosal cylic acid and at least one abietic compound.

Abstract: Baths for chemical polishing of copper or copper alloy surfaces, comprising, in aqueous solution, hydrogen peroxide, phosphoric acid and tetraborate ions.

Abstract: Baths for the chemical polishing of copper or copper alloy surfaces, comprising, in aqueous solution, hydrogen peroxide, chloride ions, phosphoric acid and phosphate and hydrogenphosphate ions, in quantities adjusted so as to impart a pH of between 1.25 and 3 to the bath.

Abstract: Hydrogen peroxide (8) is introduced at the interface of an anode (5) and an alkaline anolyte (3) of a fuel cell containing, in addition, an acid catholyte (4), isolated from the anolyte by a separator which is permeable to ions (2).

Abstract: Baths for chemical polishing of stainless steel surfaces, comprising, in aqueous solution, a mixture of hydrochloric acid, phosphoric acid and nitric acid, ferricyanide complex ions and an additive capable of decomposing nitrous acid.The baths can be used in particular for chemical polishing of heat exchangers with a very large exchange surface.

Abstract: The chemical polishing of steel surfaces is carried out by bringing the latter into contact with a bath comprising, in aqueous solution, hydrochloric acid, phosphoric acid, nitric acid and ferricyanide complex ions. The invention is in particular applicable to the polishing of vessels of large dimensions made from stainless steel alloyed with chromium and with nickel.

Abstract: The invention relates to a process for inhibiting the corrosion of an installation, made of a material chosen from amongst the metals which are less noble than hydrogen, and their alloys, in contact with an acid bath containing an alkylpyridinium chloride.A soluble cyanide complex, which is capable of forming an insoluble compound by reacting with ferric ions in the bath, is added to the bath so as to limit the concentration of the ferric ions in the bath to a maximum of 30 mg/kg. The content of ferric ions in the bath is controlled by means of a potentiometric measurement so as to bring the potential of the bath into the region of a predetermined value.The invention applies in particular to the treatment of baths for cleaning or descaling steel installations.

Abstract: The invention relates to a process and a device for monitoring the change in the surface condition of a metal component in an installation containing an ionic phase, by a modification of the working conditions in the installation, relative to standard working conditions. The equilibrium potential of the component in the ionic phase in the installatoin is applied to one electrode of an electrochemical measuring cell, the electrode and the cell respectively reproducing the metal component and the installation under standard working conditions, and the intensity of the resulting electric current in the measuring cell is measured. The invention applies, in particular, to the monitoring of the corrosion of the wall of a steel pipeline through which a sodium chloride brine passes.

Abstract: Process for polymerizing in a reactor containing a polymerization mixture, and in aqueous suspension, a halogen-containing vinyl monomer, using a lipo-soluble initiator which generates free radicals, in the presence of an effective amount of an inhibitor of crust formation derived from a sulfur-containing organic compound, wherein the inhibitor of crust formation consists of anions derived from at least one arylsulfonic acid.

Abstract: The corrosive, erosive and/or encrusting effects of a liquid on metal surfaces are monitored by immersing a metallic probe into the liquid, and measuring simultaneously both the differential capacitance of the double layer between the probe and the liquid and the resistance between the probe and an auxiliary electrode, which are representative of the surface condition of the probe.