摘要:
A method for making sand particle foundry mold members. Sand particles are coated with an aqueous dispersion of a suitable binder material such as a gelatin gel. The moist gelatin coated particles are gravity fed into a pattern box for the mold member and subjected to multi-axis vibration to pack the sand in the pattern box. The moist sand is then heated with radio frequency energy to promote binder flow to the corners of the particles, and air flow is initiated to transport water from the mass of particles to harden the mass of particles into the mold member.
摘要:
A mold for a prototype metal casting or the like may advantageously be made by forming a casting pattern of adhesively bonded aggregate particles using a binder containing a principle constituent that is soluble in supercritical carbon dioxide; forming a rigid shell mold about the pattern of materials that are unaffected by supercritical carbon dioxide; thereafter exposing the pattern and mold combination to supercritical carbon dioxide to remove the pattern binder adhesive and leave unbonded aggregate particles in the mold and removing the aggregate particles from the mold to leave a mold cavity that faithfully defines the pattern shape.
摘要:
Coating foundry sand with a thin layer of an oxidation-promoting catalyst. Preferred catalysts comprise ferric and cupric oxides. The catalysts promote the oxidation of any polymeric binder or residues admixed with the sand. The sand is coated by wetting the grains with a solution of a catalyst precursor, drying the sand and baking the sand in air to convert the precursor to the catalyst.
摘要:
Sand mold for shaping molten metal cast into the mold. The mold includes sand, a thermally oxidizable polymer amongst the grains of the sand, and a catalyst coating on the gains for promoting the thermal oxidation and breakdown of the polymer in the course of removing the sand from the casting and/or reclaiming the sand for reuse. The catalyst coating adheres so tenaciously to the grains of sand that the sand can withstand repeated casting and sand reclamation cycles without the need to replenish the catalyst.
摘要:
In the lost foam casting of aluminum, coating a fugitive pattern with a refractory coating containing a thermally stable, water-insoluble, acid-gasifiable (e.g. CaCO3) compound, and contacting the casting, with the coating thereon, with an acid to dissociate and gasify the compound and rupture the coating. Preferably, any thermal degradation products from the pattern residing in the coating are neutralized to promote wetting of the coating.
摘要:
Coating foundry sand with a thin layer of an oxidation-promoting catalyst. Preferred catalysts comprise ferric and cupric oxides. The catalysts promote the oxidation of any polymeric binder or residues admixed with the sand. The sand is coated by wetting the grains with a solution of a catalyst precursor, drying the sand and baking the sand in air to convert the precursor to the catalyst.
摘要:
A method of making metal nanostructures having a nanometer size in at least one dimension includes preparing an aqueous solution comprising a cation of a first metal and an anion, and mixing commercial elemental powder particles of an elemental second metal having a greater reduction potential than the first metal with the aqueous solution in an amount that reacts and dissolves all of the second metal and precipitates the first metal as metal nanostructures. The temperature and concentration of the aqueous solution and the selection of the anions and the second metal are chosen to produce metal nanostructures of a desired shape, for example ribbons, wires, flowers, rods, spheres, hollow spheres, scrolls, tubes, sheets, hexagonal sheets, rice, cones, dendrites, or particles.
摘要:
Particles of a macro-porous ion exchange resin are dispersed in a solution of a transition metal compound, such as a compound of molybdenum, tungsten, or vanadium. The resin may be composed for anion exchange or cation ion exchange and, correspondingly, anions or cations of the metal are exchanged onto active ion exchange sites on the molecular chains of the resin. The resin is then carbonized and graphitized to form nanometer-size particles of transition metal carbide on particles of graphite. The composite metal carbide and graphite particles are electrically conductive and serve well as support particles for later deposited particles of a platinum group metal or other catalyst material in, for example, a catalytic electrode member in an electrochemical cell.
摘要:
One illustrative embodiment includes materials and devices including an integrated hydrogen storage structure including a plurality of continuously connected thermally conductive elongated members, the elongated members including continuously connected openings between the elongated members; and, a metal hydride material contacting the elongated members and disposed within the connected openings and surrounding the elongated members.
摘要:
A method of making metal nanostructures having a nanometer size in at least one dimension includes preparing an aqueous solution comprising a cation of a first metal and an anion, and mixing commercial elemental powder particles of an elemental second metal having a greater reduction potential than the first metal with the aqueous solution in an amount that reacts and dissolves all of the second metal and precipitates the first metal as metal nanostructures. The temperature and concentration of the aqueous solution and the selection of the anions and the second metal are chosen to produce metal nanostructures of a desired shape, for example ribbons, wires, flowers, rods, spheres, hollow spheres, scrolls, tubes, sheets, hexagonal sheets, rice, cones, dendrites, or particles.