Abstract: The treatment of the external surfaces of condenser tubes, such as those used in power station condenser plants, with certain inorganic chemical compounds renders those surfaces or parts thereof sufficiently water-repellent so as to prevent the formation thereon, during operation of the condenser, of condensate films. Instead of continuous condensate films forming on the treated condenser tube surfaces during operation of the condenser, condensation is formed as discrete droplets of water which run down and drip off the tubes with the result that the condenser plant can work at higher levels of efficiency. Suitable chemical substances for use in the treatment of condenser tube surfaces include Cr VI anions, Cr.sup.3+ ions, and alkali metal tungstates, vanadates and molybdates.

Abstract: An apparatus for measuring the thickness of a coating of, for example, paint or other electrically non-conductive material on a metallic base comprises a sensor head housing an electrical measuring coil and supported above the coating on a cushion of air. The air is supplied at a constant predetermined pressure to nozzles carried by the sensor head, and a constant force urging the sensor head towards the surface of the material is yieldably applied to the sensor head through a spring.

Abstract: An apparatus suitable for measuring the surface temperature of a moving strip at an elevated temperature comprises a sensing head connected to a pneumatic actuator through a ball joint. Air under pressure is supplied to a chamber in the head and flows through a ring of passages to form an air cushion between the sensing head and the surface S whose temperature is to be measured. Part of the air flows inward across the surface S to a central aperture in the bottom plate of the head and its temperature is measured by a thermocouple in the aperture. The aperture leads to a cavity above plate and the cavity is vented by passages. The temperature recorded by the thermocouple is a measure of the temperature of surface S.

Abstract: A zinc/aluminum alloy feedstock containing 18-30% by weight Al, 0.003-0.2% by wt. Mg, 0.5-2.5% by wt. Cu, 0.02-0.5% by wt. Fe, 0-0.1% by wt. Si, Zn balance (including any impurities) is capable of achieving high plasticity at temperatures of 240.degree. C. or above after being subjected to a multistage heat treatment including an extrusion step.

Abstract: The invention relates to a continuous method of removing tin from lead. The method comprises maintaining a pool of molten lead at a temperature of from 510.degree. C. to 570.degree. C., introducing molten lead into the pool, injecting chlorine and oxygen into the molten lead in an amount to react with tin present as an impurity in the lead to form a tin-containing dross and then separating the lead from the dross.Separation may either be performed in the reaction vessel itself or in a separate settlement vessel.

Abstract: A method of depositing a protective chromite conversion coating is described. The chromite coatings produced by the method contain no Cr.sup.VI. The electrolyte used in the method comprises Cr.sup.III ions in a concentration of not more than 1 molar and a weak complexing agent for Cr.sup.III ions. The electrolyte, preferably, also contains conductivity salts. The method involves using a cathode current density of not more than 2000 amps per square meter and a temperature of not more than 35.degree. C. for a period of not more than 3 minutes. The chromite conversion coatings can be improved by aging and can be subsequently painted or lacquered. The Cr.sup.III electrolytes used are much less corrosive than Cr.sup.VI electrolytes and thus the substrates which can be coated include materials which cannot readily be chromate coated because they are reactive towards Cr.sup.VI electrolytes.

Abstract: A nickel electroplating bath comprises in aqueous solution at a pH of from 4 to 7, nickel ions at a Molar concentration of at least 0.25, chloride ions at a Molar concentration of at least 0.25, and a weak complexant for the nickel selected from formate, acetate, citrate, glutamate, anions and lactones of sugar acids and anions and lactones of acids having the formula X(C.sub.n H.sub.2n)COOH where X is OH or NH.sub.2 and n is 1 to 5, preferably 1 to 2, present at a Molar concentration of from 0.5 to 4.0 times that of the nickel. These baths have good throwing power and can be operated at convenient temperatures and pH values and at lower nickel ion concentrations than hitherto.

Abstract: A method of producing chromium conversion coatings is described. The coatings are novel in that they are chromite i.e. Cr.sub.2 O.sub.3 coatings rather than the conventional chromate i.e. CrO.sub.3 coatings. The invention includes a novel electrolyte for depositing chromite layers. The electrolyte is an aqueous solution containing Cr.sup.III ions, a weak complexing agent for Cr.sup.III ions and a poison for the electrodeposition of chromium metal. The electrolyte preferably also contains conductivity salts and may include other additives such as fluoride ion and boric acid. Examples of poisons are Cr.sup.VI ions, peroxide, nitrate, polyamines, phosphates and formaldehyde. The chromite conversion coatings can be improved by aging and can be subsequently painted or lacquered. The electrolytes of the present invention are much less corrosive than Cr.sup.VI electrolytes and thus the substrates which can be coated include materials which cannot readily be chromate coated because they are reactive towards Cr.sup.