Abstract:
A thin-walled metal part, and a method to fabricate such a part out of various alloys. A plurality of layers are formed, each of the layers being formed on a polymer template or on a previously formed layer. A homogenizing heat treatment is used to cause chemical elements in the layers to interdiffuse, to form a single continuous layer with a substantially uniform alloy composition.
Abstract:
The present invention provides a Cr-rich cathodic arc coating, an article in turbine blade coated with the chromizing over cathodic arc coating, and a method to produce the coating thereof. The Cr-rich cathodic arc coating in the present invention comprises a cathodic arc coating and a diffusion coating deposited atop the cathodic arc coating to enforce hot corrosion resistance. The hardware coated with the chromizing over cathodic arc coating in the present invention is reinforced with superior-hot corrosion resistance. The present invention further provides a novel method for producing the chromizing over cathodic arc coating by re-sequencing coating deposition order. The method in the present invention is efficient and cost-reducing by eliminating some operations, e.g., DHT and peening, between the cathodic arc coating and the diffusion coating. The hot corrosion resistance in the present invention results from the high Cr content in the surface of the coating.
Abstract:
Very good masking of pack diffusion aluminizing or chromizing on any metal to keep portions from being diffusion coated, is effected by localized coating the lowest layer of which is depletion-reducing masking powder the metal portion of which can have same composition as substrates, mixed with inert refractory diluent and non-contaminating film-former such as acrylic resin. The upper coating layer can be of non-contaminating particles like nickel or Cr.sub.2 O.sub.3 that upon aluminizing or chromizing become coherently held together to form a secure sheath. Such sheath can also be used for holding localized diffusion-coating layer in place. Film-former can be dissolved in volatile solvent, preferably methyl chloroform, in which masking powder or sheath-forming powder is suspended. Chromizing can be performed before aluminizing for greater effects. Aluminizing of metals like iron and nickel followed by leaching out much of the diffused-in aluminum, gives these substrates a pyrophoric and catalytic surface. Foil, wire or powder can be thus activated, and very fine activated powder when discharged into the air forms warm cloud that settles very slowly and decoys heat-seeking missiles.
Abstract:
Heating or heat generation in general can be from activated aluminides of molybdenum, zirconium or other similar ignitible metals. Activation is by leaching out some of the aluminum and leaves a product which is highly pyrotechnic but not pyrophoric. Activation of such alloy renders activated surface porous so it car receive impregnants such as lubricants to thus act as a bearing. Pyrotechnic webs for use as decoys against heat-seeking missiles can be folded so that portions interfere with the free radiation of other portions, to thus extend the time the webs remain at high temperature. The folding also improves the trajectory through which the webs fall when discharged into the air. The web can be coated with a thin layer of powdered silica, alumina or zirconia to increase the proportion of its radiation in the 8 to 14 micron range.
Abstract:
A corrosion resistant contiguous duplex chromium-carbon-iron alloy layer bonded to a steel and other similar ferrocarbon substrate for use as a cell casing for a sodium-sulfur cell. The outer layer includes in excess of 60 weight % chromium. The duplex layer is formed by pack chromizing in a pack of chromium and ammonium halide at elevated temperatures in hydrogen or inert gas atmosphere.
Abstract:
Low temperature aluminum diffusion is of better quality when effected with a pack energized by aluminum chloride or other material that does not generate nitrogen and is shielded from contacting the work pieces until after the pack is heated to energizing temperatures. The resulting aluminizing very effectively protects steels against corrosion in marine atmospheres, particularly when there is a chromate-type coating applied over the aluminizing. Highly effective chromate-type coating mixture consists essentially of aqueous solution of chromic and phosphoric acid also containing magnesium salts of said acids with or without dispersed polytetrafluoroethylene particles. The salts of divalent metals such as calcium, zinc, strontium, manganese, cobalt and nickel whose chromates are soluble in acid, can be used instead of or in addition to the magnesium. Such coating mixture is best applied over porous pre-coating of colloidal inert particles.
Abstract:
RICH CHROMIUM DIFFUSION COATING ON TD NICKEL OR TD NICHROME IS OBTAINED IN ONE STEP BY EMBEDDING WORK IN CHROMIUM DIFFUSION COATING PACK CONTAINING NICKEL WITH OR WITHOUT SOME COBALT, AND HELD IN UNSEALED RETORT CUP AT LEAST 15 INCHES HIGH. MAGNESIUM HALIDE IS HELPFUL TO HAVE IN THE PACK AND PACK CAN ALSO CONTAIN METALLIC IRON TO REDUCE COATING TEMPERATURE. MASKING IS ARRANGED BY COVERING THE SITES TO BE MASKED WITH A LAYER OF A MIXTURE OF NICKEL POWDER AND INERT FILLER. FOR BETTER HIGH TEMPERATURE OXIDATION RESISTANCE THE CHROMIUM-RUCH COATING IS COVERED BY AN ALUMINUM DIFFUSION COATING FROM A SIMPLE ALUMINUM DIFFUSION PACK OR ONE THAT HAS THE ALUMINUM MIXED WITH CHROMIUM. LOW TEMPERATURE ALUMINUM DIFFUSION IS MORE UNIFORM WHEN PACK ENERGIZER IS ALUMINUM CHLORIDE OR OTHER MATERIAL THAT DOES NOT GENERATE NITROGEN. A MANGANESE-CONTAINING ALUMINIZING PACK GIVES BETTER PROTECTION THAN A SIMPLE ALUMINIZING PACK, PARTICULARLY AGAINST MARINE CORROSION, AND WHEN THERE IS A CONVERSION COATING APPLIED OVER THE ALUMINIZING. CONVERSION COATING MIXTURE WETS ALUMINIZED FERROUS SURFACE BETTER WHEN THE BLACK IS THEN REMOVED WITH THE HELP OF NITRIC ACID. ALUMINIZED SUPERALLOY CAN BE HEATED IN AIR TO WHITEN IT, THEN CLEANED TO GIVE PRODUCT HAVING MORE ADHERENT CASE. ALSO ADDING SOME LANTHANUM OR YTTRIUM TO SUPERALLOY LIKE WI 52 GIVES BETTER HIGH TEMPERATURE RESISTANCE.
Abstract:
A sliding component having a wear-resistant coating includes a sliding component formed of a Ni alloy, and a wear-resistant coating provided on a sliding surface of the sliding component. The wear-resistant coating has, at least on the surface side thereof, an Al-containing Co alloy layer which contains Co as a main component, at least one of W, Ni, Mo, Fe, Si, and C, Cr, and 0.3% by mass or more and 26% by mass or less of Al.