摘要:
A method of applying a protective coating to an article comprises the steps of a) depositing aluminum in a surface region of an article, and b) depositing chromium is the surface region of the article subsequent to step a), whereby at least a portion of the chromium replaces at least a portion of the aluminum. Another method and an article are also disclosed.
摘要:
A method and treating material are presented for forming a mixed carbide layer of Va-Group elements on the surface of a carbon-containing ferrous-alloy material. The molten bath is made by introducing one or more oxides of Va-Group elements and one or more metals or alloys of Va-Group elements (other than the elements forming the oxides) into a molten bath composed of boric acid, a borate or a mixture thereof. The mixed carbide layer formed on the surface of the article is very smooth, wear resistant and corrosion resistant.
摘要:
A method for forming a boron-containing carbide layer on the surface of a ferrous alloy article by dipping the article in a molten bath. The bath is made by introducing boron and an oxide of a Va-Group element or of chromium into molten boric acid or a borate bath. The ratio of the boron to the oxide is between 7% and 40%. The carbide layer formed is very hard and has good oxidation resistance.
摘要:
A method for forming a carbide layer of a V-a group element of the periodic table on the surface of an iron, ferrous alloy or cemented carbide article in a treating molten bath, comprising heating a boric acid or borate up to its molten state to form a molten bath, dipping a metal containing a V-a group element into the molten bath, applying an electric current to the molten bath through said metal, which works as its anode, for anodically dissolving said metal into the molten bath to prepare the treating molten bath, and immersing the article in the treating molten bath, thereby forming a very hard carbide layer of said Va group element on the surface of said article. The method of this invention can form a very smooth carbide layer on the surface of the article.
摘要:
A method for forming a carbide layer of a V-a group element V, Nb or TA of the periodic table on the surface of an iron, ferrous alloy or cemented carbide article in a treating molten bath, comprising heating a mixture of boric acid or a borate and a chloride of said V-a group element of the periodic table to its fusing state and immersing the article in the treating molten bath of said mixture, thereby forming a very hard carbide layer of said V-a group element on the surface of said article. The method of this invention can be carried out without ageing the treating bath and can form a very smooth carbide layer on the surface of the article.
摘要:
The present invention relates to a process for the continuous preparation of core-shell nanoparticles, comprising a core of a core material, preferably of a semiconductor material, and a shell of a shell material, preferably of a semiconductor material, wherein selected starting materials for the shell material are mixed with a dispersion of nanoparticles of the core material and are passed continuously through a reaction zone of a tubular reactor, and other starting materials for the shell material are fed to the reaction zone of the tubular reactor at two or more locations, preferably via a tubular membrane, and the starting materials for the shell material react in the reaction zone to form a shell around the nanoparticles of the core material. The invention also relates to the tubular reactor with the membrane and its use for the continuous synthesis of core-shell nanoparticles.The invention also relates to core-shell nanoparticles comprising a core of a core material, preferably of a first semiconductor material, and an outer shell of a shell material, characterized in that, between core and shell, there is only a layer of a transition zone, in which the proportion of the core material gradually decreases toward the shell, while the proportion of the shell material gradually increases.
摘要:
Vanadium carbide layers are produced on iron and iron alloys having a content of at least 0.1 weight % carbon by treating the workpiece at 800.degree. to 1100.degree. C. in a salt bath which contains 1-30 weight % of vanadium or ferrovanadium powder. The salt bath consists of alkaline earth and/or alkali metal halide.
摘要:
A method for forming a carbide layer on the surface of a carbon-containing ferrous alloy article or a cemented carbide article in a molten treating bath. The bath is prepared by introducing 5 to 20% by weight of alumina into molten boric acid or borate bath and a carbide-forming element dissolved therein. By employing the treating bath of this invention, the life of the bath can be remarkably improved, and no sintered substance of undissolved carbide-forming element is produced in the treating bath. Further, it is possible to reduce markedly the corrosion of the article and of the vessel holding the bath.
摘要:
A process for the surface treatment of an iron or iron alloy stock comprising heating a mixture of boric acid or borate. A V-a group element of the periodic table consisting of vanadium, niobium and tantalum, or a substance containing the same, and carbon or a carbon containing substance to its fusing state in a bath vessel, and immersing the stock in the molten bath of said mixture, thereby forming a carbide layer of said element on the stock thus treated. The present invention can be performed without adding carbon to a mixture in the case when either said stock or said vessel includes carbon.