75 results about "Unidirectional solidification" patented technology

A silicon casting apparatus for producing polycrystal silicon ingot by heating a silicon melt (8) held in a mold (4) from above by a heater (3) and cooling it from below while changing the heat exchange area of a heat exchange region (HE), defined between a pedestal (5) having the mold (4) placed thereon and a bottom cooling member (6), in such a manner as to keep pace with the rise of the solid-liquid interface of the silicon melt (8), thereby causing unidirectional solidification upward along the mold (4); and a method of producing polycrystal silicon ingot using such apparatus. According to this production method, the temperature gradient given to the silicon melt (8) can be maintained at constant by adjusting the heat exchange area, so that polycrystal silicon ingot having good characteristics can be produced with good reproducibility.

A multi-layer metallurgical product comprising a core aluminum alloy, purposefully tailored through chemistry and processing route to resist recrystallization during the brazing cycle to intentionally exploit the higher strengths immediately after brazing of a deformed and recovered microstructure, the core aluminum alloy being positioned on one side to an aluminum alloy interliner designed to be resistant to localized erosion, which, in turn, is adjacent to a 4xxx cladding alloy. The multi-layer product can be fabricated at least in part via any multi-alloy ingot casting processes such as the Simultaneous Multi-Alloy Casting process or the Unidirectional Solidification of Castings process.

The invention belongs to the material preparation field, which provides a controllable temperature gradient unidirectional solidification device and a method and is applicable to the preparation of the material with magnetic anisotropy and structural anisotropy. The unidirectional solidification device consists of fusion, heat preservation, a pull-down mechanism, a cooling system and a control system. The fusion, unidirectional solidification and thermal processing are completed on the same device. By adjusting the relative position of a movable cooling ring (13) and a solid liquid interface, the temperature gradient of the solid liquid interface in the solidification process is controlled. The cooling ring and the solid liquid interface can be regulated and controlled at 10 to 200mm. The temperature gradient of the solid liquid interface can be regulated and controlled at 5 to 500 degrees centigrade/cm. The invention is applicable to the preparation of the rare earth giant magnetostrictive material, the Nd-Fe-B permanent magnet material and the samarium-cobalt permanent magnet material with magnetocrystalline anisotropy and the high temperature ally and steel material with the structural anisotropy. The invention has the advantages of stable technology, the good consistency of the prepared unidirectional solidification material and high finished product rate.

The invention relates to a method for recovering silicon carbide, high-purity silicon and dispersion liquid from silicon material linear cutting waste mortar, which is characterized in that the solid and liquid separation on the waste mortar is carried out, recovered dispersing agents are obtained after the liquid is refined, solid is washed by water for further removing residual dispersing agents, then, flotation liquid is used for carrying out floatation for many times, crude silicon carbide and crude silicon powder are separated, the recovered silicon carbide is obtained after the crude silicon carbide is refined, the crude silicon powder is treated through acid cleaning, drying, melting, plasma refining, vacuum refining, unidirectional solidification and the like, and the solar grade polysilicon is obtained. The method has the advantages that the important indexes such as the viscosity, the acid-base degree and the like of the recovered dispersing agents are more similar to those of the novel dispersing liquid, more cutting capability of the silicon carbide can be recovered after the silicon carbide is subjected to the silicon corrosion treatment, metal impurities in high-purity silicon powder are removed, an important index of the phosphorus and boron content of the solar grade silicon is reduced to a value conforming to the solar grade silicon requirements that the phosphorus is lower than 0.01 ppmw and the boron is lower than 0.16ppmw, and the attenuation of the photoelectric conversion efficiency is greatly reduced after solar batteries are made.

A process and apparatus for purifying low-purity silicon material and obtaining a higher-purity silicon material is provided. The process includes providing a melting apparatus equipped with an oxy-fuel burner, and melting the low-purity silicon material in the melting apparatus to obtain a melt of higher-purity silicon material. The melting apparatus may include a rotary drum furnace and the melting of the low-purity silicon material may be carried out at a temperature in the range from 1410° C. to 1700° C. under an oxidizing or reducing atmosphere. A synthetic slag may be added to the molten material during melting. The melt of higher-purity silicon material may be separated from a slag by outpouring into a mould having an open top and insulated bottom and side walls. Once in the mould, the melt of higher-purity silicon material can undergo controlled unidirectional solidification to obtain a solid polycrystalline silicon of an even higher purity.

Molten metal is injected uniformly into a horizontal mold from a feed chamber in a horizontal or vertical direction at a controlled rate, directly on top of the metal already within the mold. A cooling medium is applied to the bottom surface of the mold, with the type and flow rate of the cooling medium being varied to produce a controlled cooling rate throughout the casting process. The rate of introduction of molten metal and the flow rate of the cooling medium are both controlled to produce a relatively uniform solidification rate within the mold, thereby producing a uniform microstructure throughout the casting, and low stresses throughout the casting. A multiple layer ingot product is also provided comprising a base alloy layer and at least a first additional alloy layer, the two layers having different alloy compositions, where the first additional alloy layer is bonded directly to the base alloy layer by applying the first additional alloy in the molten state to the surface of the base alloy while the surface temperature of the base alloy is lower than the liquidus temperature and greater than eutectic temperature of the base alloy −50 degrees Celsuis.

The invention relates to a giant magnetostrictive large volume Fe81Ga19 alloy material and a preparation method thereof, belonging to the technical field of the alloy material and the atom percent of the alloy material is Fe81at.% and Ga19 at.%; the preparation method comprises the steps of Fe element and Ga element arc melting, solidification remelting superheat cycle process and high undercooling activation unidirectional solidification. The invention adopts high undercooling activation process so that Fe-Ga alloy blocks can be obtained while the alloy has the giant magnetostrictive property. The magnetostrictive strain of the Fe-Ga alloy blocks is above 500*10 generally and the maximum magnetostrictive strain can reach 830*10.

Molten metal is injected uniformly into a horizontal mold from a feed chamber in a horizontal direction at a controlled rate, directly on top of the metal already within the mold. A cooling medium is applied to the bottom surface of the mold, with the type and flow rate of the cooling medium being varied to produce a controlled cooling rate throughout the casting process. The rate of introduction of molten metal and the flow rate of the cooling medium are both controlled to produce a relatively uniform solidification rate within the mold, thereby producing a uniform microstructure throughout the casting, and low stresses throughout the casting.

The present invention discloses a kind of unidirectional solidification smelting furnace. It includes the following main several portions: crucible, refractory external heat-insulating stool with hollow structure, internal heat-insulating stool, radiation bearing plate, lifting hoop, circular recessed groove and elastic sealing ring, lifting screw rod, water cooler and lifting worm, sliding supporting plate, lifting servo motor and speed-reducing control device. Said invention also provides the connection mode of all the above-mentioned portions and concrete operation method of said smelting furnace.

The invention refers to a silicon purification method which utilizes eutectic reaction to separate out crystals of silicon crystal from Al-Si meltwater at a temperature lower than a silicon melting point. Solid materials composed of aluminum, silicon and other elements are thrown into a cooling crucible. The cooling crucible is a bottomless conductive cooling crucible (7) and at least part of the cooling crucible in a direction of principal axis is divided into a plurality of parts in a peripheral direction; the periphery of the cooling crucible is enclosed with inductance coils (8) and a support table (14) is arranged below the cooling crucible. Meanwhile, electromagnetic induction caused through the inductance coils at a temperature lower than a silicon melting point and higher than an eutectic temperature in the cooling crucible melts the solid materials to cool crystals and separate out silicon crystals on a solidification interface below the Al-Si meltwater and the support table is used for pulling down crystallized silicon crystals to realize continuous unidirectional solidification and manufacture silicon ingot (3). The silicon purification method can simply and accurately implement unidirectional solidification and devices are not complicated and have the characteristics of high efficiency, low energy consumption and costs; metal grade silicon can be used as raw materials to produce solar polycrystalline silicon.

A process for purifying low-purity metallurgical grade silicon, containing at least one contaminant and obtaining a higher-purity solid polycrystalline silicon is provided. The process includes containing a melt of low-purity metallurgical grade silicon in a mould having insulated bottom and side walls, and an open top; solidifying the melt by unidirectional solidification from the open top towards the bottom wall while electromagnetically stirring the melt; controlling a rate of the unidirectional solidification; stopping the unidirectional solidification when the melt has partially solidified to produce an ingot having an exterior shell including the higher-purity solid polycrystalline silicon and a center including an impurity-enriched liquid silicon; and creating an opening in the exterior shell of the ingot to outflow the impurity-enriched liquid silicon and leave the exterior shell which has the higher-purity solid polycrystalline silicon.

The invention relates to a production method of industrial silicon, comprising the steps: preparation of raw materials, reduction reaction, deslagging and unidirectional solidification. The invention solves the technical problem that the existing industrial silicon production methods fail to solve the problems of upward of a hearth and high content of impurities, thereby having the advantages of low content of impurities, removal of upward situation of the hearth, rapid reaction speed, low energy consumption and simple structure of an oven body.

An alloy composition and method by which the incidence of freckling can be reduced in castings produced with properties similar to the René N5 nickel-base superalloy. The casting has a unidirectional crystal structure and a composition consisting of, by weight, 6% to 8% chromium, 6% to 9% cobalt, 0% to 2% molybdenum, 4% to 6% tungsten, 6.4% to 6.9% tantalum, 0% to 2% titanium, 5% to 7% aluminum, 2.7% to 3.0% rhenium, 0.3% to 0.7% haffiium, 0.04% to 0.08% carbon, 0.002% to 0.006% boron, 0% to 0.075% yttrium, 0.002% to 0.004% zirconium, the balance being nickel and incidental impurities.

Methods and apparatus for manufacturing high purity polysilicon. The apparatus includes a vacuum chamber; first and second electron guns disposed at an upper side of the vacuum chamber to irradiate electron beams into the vacuum chamber; a silicon melting unit which is placed on a first electron beam-irradiating region corresponding to the first electron gun and to which powdery raw silicon is fed and melted by the first electron beam; and a unidirectional solidification unit placed on a second electron beam-irradiating region corresponding to the second electron gun. The unidirectional solidification unit is provided therein with a start block driven in a downward direction to transfer molten silicon in the downward direction and is formed at a lower side thereof with a cooling channel. The start block includes a dummy bar having a silicon button joined to an upper portion of the dummy bar.

The invention discloses a grain structure three-dimensional numerical prediction method in a molten metal one-way solidification process, and belongs to the field of metal material machining. The method aims at solving the problems that an existing simulation calculation method is large in three-dimensional numerical prediction calculation amount and does not consider the influence of solid-liquidinterface energy on grain growth when a three-dimensional cellular automaton model is adopted for simulating the molten metal solidification process and carrying out three-dimensional representationon a grain structure. The method comprises the steps of dividing grids for a computational domain and determining grid identifiers; endowing each grid with a state variable; forming a subdivision steplength confirmation file on the basis of a grid Euler angle calculation result obtained by calculation of each subdivision step length in all time step lengths; calculating to obtain the maximum subdivision step length meeting the requirement; predicting the solidification process of an actual casting, and taking the grids with the same Euler angle in each time step as the same crystal grain. According to the method, the calculation speed of numerical prediction in the actual solidification process is increased.

The invention belongs to the technical field of purification of polysilicon by a physical metallurgical technology. A method for purifying polysilicon by utilizing a shallow molten pool to carry out vacuum smelting comprises the following steps of: under the high-volume condition with the vacuum degree below 0.001Pa, firstly melting a high purity polysilicon material in a smelting crucible by induction heating at a temperature of 1,430 to 1,460 DEG C to form high purity silicon solution, keeping the liquid state of the high purity silicon solution, and then heating the high purity silicon solution so that the temperature of the high purity silicon solution reaches 1,500 to 1,600 DEG C; continuously and slowly adding a rod with high phosphorus content and high metal silicon content into the silicon solution, continuously evaporating to remove a phosphorus impurity in the shallow molten pool; and after the rod with high phosphorus content and high metal silicon content is totally molten into the molten pool, keeping the silicon solution in the liquid state for a certain time in the smelting crucible at a temperature of 1,450 to 1,500 DEG C through induction heating, carrying out unidirectional solidification and cutting off the polysilicon with high content of metal impurities on the top of a silicon ingot. In the invention, a high-temperature high-vacuum large-area shallow molten pool smelting technology and an unidirectional solidification technology are integrated; the method has good purifying effect, is simple to operate, has low cost and high production efficiency and is suitable for batch production; and resources are saved.