摘要:
The present invention concerns a process for preparing ferrous parts of a color television tube and a furnace for operating such a process.According to the invention, each ferrous part behind the base of the television tube, is prepared in a single furnace and undergoes successively an annealing, a reduction and an oxidation in three parts of the furnace 3, 4 and 5, in such a way as to eliminate the mechanical stresses, remove the rust and deposit homogeneous and adhesive layers of iron oxides I and II.
摘要:
In aluminum-containing stainless steel foil, the presence of magnesium impurity in an amount greater than about 0.002 weight percent has been found to inhibit formation of a preferred oxide surface layer characterized by multitudinous oxide whiskers of a type suitable for tightly bonding an applied coating. A method for purifying magnesium-contaminated foil comprises heating the foil to selectively vaporize the magnesium while avoiding incipient melting of the base alloy, preferably between about 1000.degree. C. and 1150.degree. C. The magnesium vapors escape into a suitable ambient phase such as a vacuum or a dry hydrogen gas. Thereafter, the foil is oxidized under conditions effective to produce the desired whiskers. A preferred steel is composed of an iron-base alloy comprising about 15 to 25 weight percent chromium and 3 to 6 weight percent aluminum, and optionally may contain cerium or yttrium in an amount effective to promote oxide adherence.
摘要:
Selective surfaces for photothermal solar collectors consisting of a nickel support, preferably commercial nickel of 99.5% purity, a layer of a porous nickel oxide of about 0.2 .mu.m covering the metallic support, the layer of porous nickel oxide being covered with asperities in the form of a network of nickel oxide discs in which the major portions are oriented at an angle with respect to the vertical. The network of discs has a thickness of about 2 .mu.m. The preparation of these selective surfaces is carried out in the following manner. Thin nickel plates are subjected to a heat treatment by heating and oxidizing in an oxidant gas during a short period of time at a temperature varying between about 1000.degree. C. and 1100.degree. C. The oxidized nickel plates are reduced at a temperature of about 1100.degree. C. in the presence of a reducing gas until the metallic state is obtained. The surrounding temperature is thereafter lowered between 810.degree. and 830.degree. C. and an oxidizing gas is circulated around the plates, at a rate of flow which is sufficient to flush away the reducing gas. The plates are rapidly cooled down to room temperature to give the intended selective surfaces.
摘要:
The invention provides a means for solving the difficult problem of the deposition of stain in the recesses to cause loss of beautiful appearance on the matted surface of an article for personal ornament made of titanium, zirconium or an alloy thereof formed by honing or barrel finishing. The method comprises the steps of (a) forming a first matted surface with microscopically fine protrusions and recesses on the article by honing or barrel finishing, (b) forming a hardened layer on the matted surface by nitriding, carbonizing, boriding or oxidizing, (c) partially removing the hardened layer covering the protrusions on the matted surface by a first electrolytic or chemical polishing, (d) forming a second matted surface on the article by honing or barrel finishing, and (e) partially removing the surface layer at the protrusions by a second electrolytic or chemical polishing to smoothen the surface leaving a sandy appearance.
摘要:
A process for carburizing high alloy steels comprises heating the steel at a high temperature in an oxidizing atmosphere to form a high temperature oxide on the steel surface and carburizing the steel containing the high temperature oxide. Once the high temperature oxide is formed on the steel surface, the steel can be carburized at any time thereafter.
摘要:
A superior corrosion-resistant tin-free steel is produced by vacuum depositing high-purity metallic chromium onto a thoroughly cleaned steel surface at a temperature within the range 500*1,000* F., and thereafter, before the coated steel is cooled, exposing the freshly deposited coating to an oxidizing atmosphere while the steel is at a temperature of 600* to 1,000* F. The resulting vigorous high-temperature oxidation of exposed steel at cracks and pores to magnetite produces a continuous pore-free and crack-free coating which is lustrous and metallic in appearance and provides exceptional resistance to corrosion.