摘要:
A turbine engine component (10) with a non-aluminide protective coating (14) containing silicon and chromium and a process for forming such non-aluminide protective coatings (14). The non-aluminide protective coating (14) is formed by applying a silicon-containing fluid composition to the turbine engine component (10) as a silicon-containing layer (20) and heating the silicon-containing layer (20) to a temperature effective to form the non-aluminide protective coating (14).
摘要:
The invention relates to a method for the carboxylation conversion of a metal surface under oxidising conditions in relation to the metal, consisting in bringing the metal into contact with a hydro-organic or aqueous bath containing a mixture of organic acids. The invention is characterised in that: the organic acids comprise saturated linear carboxylic acids having between 10 and 18 carbon atoms; the mixture comprises a binary or ternary mixture of such acids; the respective proportions of said acids are such that (i) for a binary mixture x ± 5 % - y ± 5 %, wherein x and y represent the respective proportions, in molar percentages, of the two acids in a mixture with the composition of the eutectic and (ii) for a ternary mixture x ± 3 % - y ± 3 % - z ± 3 %, wherein x, y and z represent the respective proportions, in molar percentages, of the three acids in a mixture with the composition of the eutectic; and the concentration of the mixture in the bath is greater than or equal to 20 g/l.
摘要:
Conversion and passivation coatings and methods for metal surfaces such as steel and aluminum are disclosed. The coating compositions comprise an aqueous sol of cerium oxide and/or silica particles and a ureido silane compound. The methods of the invention comprise contacting the requisite metal surface with the coating composition.
摘要:
The invention relates to a method for coating a metallic surface with an aqueous composition for pretreating before applying another coating or for treating said metallic surface. In addition to water, the composition contains: a) at least one hydrolyzable or at least partially hydrolyzed silane; b) at least one metal chelate, if necessary, also; c) at least one organic film former; d) at least one long-chain alcohol that serves as a film forming aid and/or; e) at least one inorganic compound in particle form. The unsoiled, scoured, cleaned and/or pretreated metallic surface is brought into contact with the aqueous composition and a film is formed on the metallic surface, is subsequently dried, compacted in part or completely by film formation and, if necessary, additionally hardened. The dried and, if necessary, additionally hardened film has a layer thickness ranging from 0.01 to 10 µm. The invention also relates to corresponding aqueous compositions.
摘要:
The invention concerns a water soluble composition for temporarily coating, in the form of a dry film, metal surfaces sensitive to atmospheric oxidation containing at least a carboxylic acid characterised in that it comprises at 20 wt.% of a combination of at least one saturated linear carboxylic monoacid and at least one unsaturated linear carboxylic acid, in the form of alkaline, alkaline-earth or amine salts, the carbon chain of each acid comprising an odd number of carbon atoms ranging from 5 to 21 and optionally at least 0.5 wt.% of a triazole derivative.
摘要:
There is provided a method for treating the surface of metals such as ferritic steels, austenitic stainless steels, copper and aluminum alloys to increase their corrosion resistance. The metals are immersed into a heated aqueous composition containing a rare earth salt. Increased corrosion resistance is obtained using nitrates of yttrium, gadolinium, cerium, europium, terbium, samarium, neodymium, praseodymium, lanthanum, holmium, ytterbium, dysprosium, and erbium nitrates. The rare earth salt is present in the range from about 2% by weight to saturation of the solution. The composition includes a pH-modifying substance such as nitric acid to adjust the pH in the range 0.5 to about 6.5 to attack the surface to remove oxides facilitating deposition of the rare earth. For aluminum alloys the pH is maintained between 4.5 to 6.5, for nickel based alloys and austenitic stainless steels the pH is maintained between 0.5 to 3.5 and between pH 2.0 to 4.5 for ferritic stainless steels. The surface can also be conditioned by abrasion before or during immersion in the composition. Increased corrosion resistance is achieved by immersion for 15 to 20 minutes with the composition maintained between 60 to 95 DEG C. Gadolinium, neodymium and praseodymium nitrate when used alone produced the greatest degree of corrosion resistance compared to the other rare earth nitrates. Significant synergistic effects are observed when combinations of two or more rare earth nitrates are used in the compositions. Compositions based on cerium nitrate, gadolinium nitrate and lanthanum nitrate are very effective in reducing crevice corrosion.
摘要:
Adhesion of rubber to a variety of metals (aluminum, stainless steel, mild steel and brass) is effectively achieved by the application of an organofunctional silane (I) and a non-organofunctional silane (II) to the requisite surface. Preferably, the organofunctional silane (I) is a vinyltrialkoxysilane with the non-organofunctional silane (II) preferably comprising an alkoxylated substituted alkyl silane. The silanes (I) and (II) are at least partially hydrolyzed and are normally provided in the form of a EtOH/H2O solution. Bonded joints formed by these adhesive treatments can withstand fuel degradation tests indicating that the treatments can be used, for example, to bond metal and rubber surfaces in automotive and other environments in which the joined parts will be contacted by fuels, oil and/or organic solvents.