JP2016128742A - Crucible material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crucible furnace capable of being used in vacuum induction melting and capable of minimizing contamination of alloy.SOLUTION: A crucible furnace includes: an outside container defining container including a susceptor, and defining an internal surface; a removable inside container contacting with the internal surface of the outside container, containing yttria, and receiving molten metal; and a system including an induction coil heating the outside container, and heating the area of the inside container not contacting with metal, until the metal is molten, with heat emitted by the outside container.SELECTED DRAWING: Figure 1

Description

  All publications, patents and patent applications cited herein are hereby incorporated by reference in their entirety.

RELATED APPLICATION This application is a crucible material for melting alloys of the same inventor Andrew Waneuk, filed on the same day on August 5, 2011, having serial number 13 / 198,906. Related to US application entitled “CRUCABLE MATERIALS FOR ALLOY MELTING”.

  Vacuum induction melting (VIM) is relatively cheap compared to the cold hearth melting technique, and a high production rate is possible. However, when VIM is selected as a method for producing amorphous alloys, there is a need for effective means to produce clean alloy feedstocks (ie, low oxygen, carbon, nitrogen, and other metal impurities). Currently, graphite is the most common crucible material used to contain melts of Zr-based amorphous alloys. The melt produced in this type of crucible typically contains high levels of carbon by diffusion of carbon atoms from the graphite-containing crucible into the melt, especially after repeated reuse. Similarly, because zirconia and alumina both react significantly with most Zr-based BMG compositions, crucibles containing these materials can often have undesirable results. Therefore, contamination is still an issue.

  Therefore, there is a need to develop a crucible that can be used in VIM and that can minimize alloy contamination by elements of the crucible material.

  One embodiment provides an article, the article includes an inner container having a cavity, the inner container includes a ceramic, the article further includes an outer container, the outer container includes a susceptor, and the outer surface of the inner container At least a portion of which is in contact with the inner surface of the outer container, and the inner container is removable from the mold. A method of melting using the present article is also provided.

  An alternative embodiment provides a method of melting, the method comprising providing a mixture of alloying elements and heating the mixture in the article to a temperature above the melting temperature of the alloying elements, The article includes an inner container having a cavity containing a feedstock, the inner container includes a ceramic, the article further includes an outer container, the outer container includes a susceptor, and at least a portion of the outer surface of the inner container is outer. In contact with the inner surface of the container, the inner container is removable from the article.

1 is a schematic diagram of a crucible design in one embodiment. FIG.

FIG. 6 is a photograph of an experimental apparatus for testing the compatibility between sialon and a Zr-based amorphous alloy. The crucible 21 is placed inside the quartz housing 22 that has been evacuated to less than 0.005 Torr. An induction coil 23 is provided around the outside of the exhaust quartz housing, the sialon crucible, and the alloy ingot 24 in the crucible. Is placed.

FIG. 3 is an alternative view of the apparatus shown in FIG. The top hose 31 is connected to a vacuum pump, and the coil 23 is connected to a radio frequency (RF) power supply (not shown).

In one embodiment, the alloy ingot is inductively melted in a sialon crucible at 1000 ° C. for about 30 minutes and the alloy is cooled to room temperature. The crucible was then intentionally broken to assess whether the alloy was wet and bonded to sialon. The alloy was found to leave the sialon completely, leaving no residue in the original crucible, indicating very low wetting, ie good suitability for alloy processing. In one embodiment, the alloy ingot is inductively melted in a sialon crucible at 1000 ° C. for about 30 minutes and the alloy is cooled to room temperature. The crucible was then intentionally broken to assess whether the alloy was wet and bonded to sialon. The alloy was found to leave the sialon completely, leaving no residue in the original crucible, indicating very low wetting, ie good suitability for alloy processing. FIG. 4B is an enlarged view of FIG.

It is a photograph showing that a large amount of copper evaporated from the alloy in 30 minutes, and the same copper deposition was observed when the boat was lined with a sialon sleeve.

In one embodiment, the photograph shows that the top of the crucible was destroyed after the alloy was rapidly heated, melted and filled into the crucible. The alloy was slowly cooled and held in a cracked crucible. Wetting between the alloy and the crucible was low and it was fairly easy to remove the crucible pieces, indicating good suitability for processing.

In one embodiment, a yttria crucible inserted into a graphite susceptor, both held in a quartz container for processing. In one embodiment, another view of a yttria crucible inserted into a graphite susceptor, both held in a quartz container for processing. In one embodiment, another view of a yttria crucible inserted into a graphite susceptor, both held in a quartz container for processing. In particular, FIG. 7 (c) shows that the alloy ingot has collapsed into the yttria crucible as a result of melting.

Phase As used herein, the term “phase” can refer to a phase that can be found in a thermodynamic phase diagram. A phase is a region of space (eg, thermodynamic system) in which the physical properties of the material throughout the region are essentially uniform. Examples of physical properties include density, refractive index, chemical composition and lattice periodicity. A brief description of a phase is a region of material that is chemically homogeneous, physically distinct, and / or mechanically separable. For example, in a system consisting of ice and water in a glass jar, ice cubes are one phase, water is the second phase, and moist air above the water is the third phase. Jar glass is another distinct phase. The phase may represent a solid solution, it may be a two-component, three-component, four-component or higher solution, or the phase may represent a compound such as an intermetallic compound. As another example, the amorphous phase is different from the crystalline phase.

Metals, transition metals and non-metals The term “metal” refers to an electropositive chemical element. As used herein, the term “element” generally refers to an element that can be found in the periodic table. Physically, a ground state metal atom includes a partially filled band having an empty state close to the occupied state. The term “transition metal” is any of the Group 3 to Group 12 metal elements of the periodic table, which have an incomplete inner electron shell, with the highest and lowest electrical positivity in a range of elements. It acts as a transition link between things. Transition metals are characterized by their ability to form multiple valences, colored compounds, and stable complex ions. The term “non-metallic” refers to a chemical element that has no ability to lose electrons and form a cation.

  Depending on the application, any suitable non-metallic element or combination thereof may be used. An alloy (or “alloy composition”) may include a plurality of non-metallic elements, such as, for example, at least two, at least three, at least four, or more non-metallic elements. The nonmetallic element may be any element found in Groups 13-17 of the periodic table. For example, nonmetallic elements are F, Cl, Br, I, At, O, S, Se, Te, Po, N, P, As, Sb, Bi, C, Si, Ge, Sn, Pb, and B Any one of these may be sufficient. Sometimes, the non-metallic element may indicate a specific metalloid (eg, B, Si, Ge, As, Sb, Te, and Po) in Groups 13-17. In one embodiment, the non-metallic element may include B, Si, C, P, or a combination thereof. Thus, the alloy may include borides, carbides, or both, for example.

  Transition metal elements are scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, silver, cadmium, hafnium, tantalum, tungsten , Rhenium, osmium, iridium, platinum, gold, mercury, ruzafodium, dobnium, seaborgium, bolium, hassium, mitonium, ununnilium, ununnium, and ununbium. In one embodiment, the BMG containing a transition metal element is Sc, Y, La, Ac, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Ru, It may have at least one of Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, and Hg. Depending on the application, any suitable transition metal element or combination thereof may be used. The alloy composition may include a plurality of transition metal elements, such as, for example, at least 2, at least 3, at least 4, or more transition metal elements.

  The alloys or alloy “samples” or “specimen” alloys described herein may have any shape or size. For example, the alloy may have a particle shape, which may be in the form of a sphere, ellipsoid, wire, rod, sheet, flake, or irregular shape, for example. The particles may have any size. For example, the average diameter of the particles is from about 1 micron to about 100 microns, such as from about 5 microns to about 80 microns, such as from about 10 microns to about 60 microns, such as from about 15 microns to about 50 microns, such as from about 15 microns to about 45 microns. For example, from about 20 microns to about 40 microns, such as from about 25 microns to about 35 microns. For example, in one embodiment, the average diameter of the particles is from about 25 microns to about 44 microns. In some embodiments, smaller particles such as those in the nanometer range, or larger particles such as those greater than 100 microns may be used.

  The alloy sample or specimen may be of a larger size. For example, the alloy sample may be a bulk structural component, such as an ingot, a housing / casing of an electronic device, or a portion of a structural component having dimensions in the millimeter, centimeter, or metric range.

Solid solution The term “solid solution” refers to a solid solution. The term “solution” refers to a mixture of two or more substances, which may be a solid, liquid, gas, or a combination thereof. The mixture may be homogeneous or heterogeneous. The term “mixture” is a composition of two or more substances that are combined with each other and generally separable. In general, the two or more substances are not chemically combined with each other.

Alloys In some embodiments, the alloy powder compositions described herein may be fully alloyed. In one embodiment, an “alloy” refers to a homogeneous mixture or solid solution of two or more metals, one atom replacing or occupying the interstitial position between the other atoms. For example, brass is an alloy of zinc and copper. An alloy is different from a composite and may exhibit a partial or complete solid solution of one or more elements in a metal matrix, such as, for example, one or more compounds in a metal matrix. The term alloy herein may refer to both a complete solid solution alloy that can provide a single solid phase microstructure and a partial solution that can provide two or more phases. The alloy compositions described herein may indicate those comprising an alloy or those comprising an alloy-containing composite.

  Thus, a fully alloyed alloy may have a homogeneous distribution of components and may be a solid solution phase, a compound phase, or both. As used herein, the term “fully alloyed” may describe slight variations within error tolerances. For example, the term indicates at least 90% alloying, such as at least 95% alloying, such as at least 99% alloying, such as at least 99.5% alloying, such as at least 99.9% alloying. May be. Percentages herein may indicate either volume percentages or weight percentages depending on the situation. These percentages may be balanced by impurities that may relate to compositions or phases that are not part of the alloy.

Amorphous or Amorphous Solid An “amorphous” or “amorphous solid” is a solid that lacks the lattice periodicity that is characteristic of crystals. As used herein, “amorphous solid” includes “glass” which is an amorphous solid that softens due to glass transition to a liquid state upon heating. In general, amorphous materials do not have long-range order characteristics like crystals, but may have some short-range order on the atomic length scale depending on the nature of chemical bonds. The distinction between an amorphous solid and a crystalline solid may be made based on lattice periodicity determined by structural characterization techniques such as, for example, x-ray diffraction and transmission electron microscopy.

  The terms “order” and “disorder” indicate the presence or absence of some symmetry or correlation in a multiparticulate system. The terms “long-range order” and “short-range order” distinguish order within a material based on length scale.

  The most exact form of order in a solid is the lattice periodicity. That is, a specific pattern (arrangement of atoms in the unit cell) is repeated many times to form a translationally invariant tiling of the space. This is a characteristic that defines crystals. The possible symmetries are classified into 14 Brave lattices and 230 space groups.

  Lattice periodicity provides long-range order. If only one unit cell is known, it is possible to accurately predict all atomic positions at any distance by translational symmetry. The reverse is usually true, except in the case of quasicrystals with completely deterministic tiling but no lattice periodicity.

  Long-range order characterizes physical systems in which distant parts of the same sample exhibit correlated behavior. This can be expressed as a correlation function, ie, a spin-spin correlation function G (x, x ′) = <s (x), s (x ′)>.

  In the above function, s is the spin quantum number and x is the distance function in a particular system. This function is equal to 1 when x = x 'and decreases as the distance | x-x' | increases. Typically, at large distances, this function decreases exponentially toward zero, and the system is considered disordered. However, when this correlation function decreases towards a constant value at large | x−x ′ |, the system is said to have long-range order. When this function decreases towards zero as a power of distance, it can be called quasi-long-range order. Note that what constitutes a large value of | x-x '| is relative.

  When some parameters that define the behavior of a system, such as spin glass, are random variables that do not evolve with time (ie, they are quenched or frozen), the system is said to exhibit a quenching disorder. It is the opposite of the annealing disorder where random variables are allowed to evolve on their own. Embodiments herein include systems that include a quenching disorder.

  The alloys described herein may be crystalline, partially crystalline, amorphous, or substantially amorphous. For example, an alloy sample / specimen may include at least some degree of crystallinity, and the particle / crystal size may be in the nanometer and / or micrometer range. Alternatively, the alloy may be substantially amorphous, for example completely amorphous. In one embodiment, the alloy powder composition is not at least substantially amorphous, for example substantially crystalline, for example completely crystalline.

  In one embodiment, the presence of a crystal or crystals in an otherwise amorphous alloy may be interpreted as a “crystalline phase” in the alloy. The degree of crystallinity of an alloy (or “crystallinity” for short in some embodiments) may indicate the amount of crystalline phase present in the alloy. The degree may indicate, for example, the fraction of crystals present in the alloy. The fraction may indicate a volume fraction or a weight fraction depending on the situation. A measure of how “amorphous” an amorphous alloy may be is amorphous. Amorphous property may be measured by the degree of crystallinity. For example, in one embodiment, an alloy having a low degree of crystallinity can be said to have a high degree of amorphousness. For example, in one embodiment, an alloy having 60 vol% crystalline phase may have 40 vol% amorphous phase.

Amorphous alloy or amorphous metal "Amorphous alloy" means an amorphous content greater than 50% by volume, preferably greater than 90% by volume, more preferably greater than 95% by volume, most preferably 99% by volume. It is an alloy having an amorphous content of almost 100% by volume from above. As noted above, it should be noted that alloys with high amorphousness simultaneously have a low degree of crystallinity. An “amorphous metal” is an amorphous metal material having a disordered atomic scale structure. Most metals are crystalline and thus have a highly ordered atomic arrangement, whereas amorphous alloys are amorphous. Materials in which such disordered structures are directly generated upon cooling from the liquid state are sometimes referred to as “glass”. Thus, amorphous metals are commonly referred to as “metallic glasses” or “glassy metals”. In one embodiment, bulk metallic glass (“BMG”) may refer to an alloy having an at least partially amorphous microstructure. However, in addition to extremely rapid cooling, there are several ways to produce amorphous metal, including physical vapor deposition, solid state reaction, ion irradiation, melt rotation, and mechanical alloying. Regardless of how it is prepared, the amorphous alloy may be a single class of material.

  Amorphous metal may be produced by various rapid cooling methods. For example, amorphous metal may be produced by sputtering molten metal on a rotating metal disk. Because rapid cooling on the order of millions of degrees per second can be too fast to form crystals, the material is “trapped” in a glassy state. In addition, amorphous metals / alloys may be produced with a critical cooling rate low enough to allow formation of amorphous structures in thick layers, such as bulk metallic glass.

  The terms “bulk metallic glass” (“BMG”), bulk amorphous alloy, and bulk solidified amorphous alloy are used interchangeably herein. These terms refer to an amorphous alloy having a minimum dimension of at least the millimeter range. For example, the dimension is at least about 0.5 mm, such as at least about 1 mm, such as at least about 2 mm, such as at least about 4 mm, such as at least about 5 mm, such as at least about 6 mm, such as at least about 8 mm, such as at least about 10 mm, such as at least about 12 mm. It may be. Depending on the geometry, the dimensions may indicate diameter, radius, thickness, width, length, etc. Further, the BMG may be a metallic glass having at least one dimension in the centimeter range, for example at least about 1.0 cm, such as at least about 2.0 cm, such as at least about 5.0 cm, such as at least about 10 0.0 cm or the like may be used. In some embodiments, at least one dimension of the BMG may be at least in the metric range. The BMG may take any of the shapes or shapes described above with respect to the metallic glass. Thus, the BMG described in some embodiments herein may differ from thin films made by conventional deposition techniques in one important aspect. That is, the former may be much larger than the latter.

  The amorphous metal may be an alloy instead of a pure metal. Alloys can contain significantly different sizes of atoms, resulting in a lower free volume in the molten state (thus having a higher order of viscosity than other metals and alloys). Its viscosity prevents the atoms from moving sufficiently to form an ordered lattice. As a result of this material structure, there may be less shrinkage during cooling and resistance to plastic deformation. In some cases, the absence of grain boundaries, which is a weakness of crystalline materials, may result in better resistance to wear and corrosion, for example. In one embodiment, the amorphous metal is technically glass, but may be much tougher and less brittle than oxide glasses and ceramics.

  The thermal conductivity of an amorphous material may be lower than its crystalline counterpart. In order to form an amorphous structure upon slower cooling, the alloy can be made of three or more components, resulting in complex crystal units with higher potential energy and lower formation probability. Good. The formation of an amorphous alloy can depend on several factors. That is, by mixing the composition of the components of the alloy, the atomic radii of the components (with a significant difference, preferably greater than 12% to achieve high packing density and low free volume), and combinations of components Negative heat, inhibition of crystal nucleation, and extended time for the molten metal to remain in a supercooled state. However, since the formation of an amorphous alloy is based on many different variables, it can be difficult to pre-determine whether an alloy composition forms an amorphous alloy.

  For example, amorphous alloys of magnetic metals (iron, cobalt, nickel) with boron, silicon, phosphorus, and other glass formers may be magnetic and may have a low coercivity and high electrical resistance. The high resistance reduces the loss due to eddy currents when subjected to an alternating magnetic field, which is a useful characteristic, for example, as a magnetic core of a transformer.

  Amorphous alloys may have a variety of potentially useful properties. In particular, amorphous alloys tend to be stronger than crystalline alloys of similar chemical composition and can sustain greater reversible (“elastic”) deformation than crystalline alloys. Amorphous metals derive their strength directly from their amorphous structure, which may have no drawbacks (such as dislocations) that limit the strength of crystalline alloys. For example, one of the modern amorphous metals known as Vitreloy ™ has a tensile strength approximately twice that of high purity titanium. In some embodiments, room temperature metallic glasses are not ductile and tend to fail suddenly when tensioned, so that imminent failures do not manifest themselves, so in applications where reliability is important. Material application is limited. Thus, to overcome this problem, a metal matrix composite material having a metallic glass matrix containing ductile crystalline metal dendritic particles or fibers may be used. Alternatively, BMGs that are low in elements (eg, Ni) that tend to cause degradation may be used. For example, the ductility of BMG may be improved by using BMG that does not contain Ni.

  Another useful property of bulk amorphous alloys is that they can be true glasses. In other words, the bulk amorphous alloy can be softened and flowed by heating. This makes it possible to perform the same processing as that of the polymer, for example, by easy injection molding. As a result, amorphous alloys can be used to make sports equipment, medical devices, electronic components and equipment, and thin films. A thin film of amorphous metal can also be deposited as a protective coating via fast oxygen fuel technology.

  The material may have an amorphous phase, a crystalline phase, or both. The amorphous phase and the crystalline phase may have the same chemical composition and differ only in the fine structure. That is, one is amorphous and the other is crystalline. Microstructure in one embodiment refers to the structure of the material as revealed by a microscope at 25 × magnification or higher. Alternatively, the two phases may have different chemical compositions and microstructures. For example, the composition may be partially amorphous, substantially amorphous, or completely amorphous.

  As described above, the degree of amorphousness (and conversely the degree of crystallinity) can be measured by the fraction of crystals present in the alloy. The degree may indicate the weight fraction and volume fraction of the crystal phase present in the alloy. A partially amorphous composition includes at least about 5 vol%, such as at least about 10 vol%, such as at least about 20 vol%, such as at least about 40 vol%, such as at least about 60 vol%, such as at least about 80 vol%, such as at least about 90 vol. % Or the like may be a composition having an amorphous phase. The terms “substantially” and “about” are defined elsewhere in this application. Thus, an at least substantially amorphous composition is one in which at least about 90 vol% is amorphous, such as at least about 95 vol%, such as at least about 98 vol%, such as at least about 99 vol%, such as at least about 99.5 vol%, For example, it may indicate at least about 99.8 vol%, such as at least about 99.9 vol%. In one embodiment, there may be some attendant minor amount of crystalline phase in the substantially amorphous composition.

  In one embodiment, the amorphous alloy composition may be homogeneous with respect to the amorphous phase. A substance with a uniform composition is homogeneous. This is in contrast to heterogeneous materials. The term “composition” refers to the chemical composition and / or microstructure of a substance. When a volume of a material is divided in half, the material is homogeneous when both halves have substantially the same composition. For example, when the volume of the particle suspension is divided in half, the particle suspension is homogeneous when both halves have substantially the same volume of particles. However, it may be possible to see individual particles with a microscope. Another example of a homogeneous material is air, where different components are equally suspended in the air, but the particles, gases and liquids in the air can be analyzed separately or separated from the air.

  A composition that is homogeneous with respect to an amorphous alloy may refer to a composition having an amorphous phase that is distributed substantially uniformly throughout the microstructure. In other words, the composition macroscopically comprises an amorphous alloy distributed substantially uniformly throughout the composition. In an alternative embodiment, the composition may be a composite composition having an amorphous phase with a non-amorphous phase therein. The non-amorphous phase may be one crystal or a plurality of crystals. The crystals may be in the form of particles of any shape, for example, spheres, ellipsoids, wires, rods, sheets, flakes, or irregular shapes. In one embodiment, the crystals may have a dendritic shape. For example, an at least partially amorphous composite composition may have a crystalline phase in the form of dendrites dispersed in an amorphous phase matrix. The dispersion may be uniform or non-uniform, and the amorphous phase and the crystalline phase may have the same chemical composition or different chemical compositions. In one embodiment, they have substantially the same chemical composition. In another embodiment, the crystalline phase may be more ductile than the BMG phase.

  The methods described herein may be applicable to any type of amorphous alloy. Similarly, the amorphous alloy described herein as a component of a composition or article may be of any type. The amorphous alloy may include the elements Zr, Hf, Ti, Cu, Ni, Pt, Pd, Fe, Mg, Au, La, Ag, Al, Mo, Nb, Be, or combinations thereof. That is, the alloy may include any combination of these elements in its chemical formula or chemical composition. These elements may be present in different weight or volume percentages. For example, an iron “based” alloy may refer to an alloy in which a minor weight percentage of iron is present, such as at least about 20 wt%, such as at least about 40 wt%, For example, it may be at least about 50 wt%, such as at least about 60 wt%, such as at least about 80 wt%. Alternatively, in one embodiment, the percentages described above may be volume percentages instead of weight percentages. Thus, the amorphous alloy may be zirconium base, titanium base, platinum base, palladium base, gold base, silver base, copper base, iron base, nickel base, aluminum base, molybdenum base, and the like. The alloy may further not include any of the above elements to suit a particular purpose. For example, in some embodiments, the alloy or composition comprising the alloy may be substantially free of nickel, aluminum, or beryllium, or a combination thereof. In one embodiment, the alloy or composite is completely free of nickel, aluminum, beryllium, or a combination thereof.

  For example, the amorphous alloy may have the formula (Zr, Ti) a (Ni, Cu, Fe) b (Be, Al, Si, B) c, where each of a, b and c is weight or atom. Represents a percentage. In one embodiment, in atomic percentages, a ranges from 30 to 75, b ranges from 5 to 60, and c ranges from 0 to 50. Alternatively, the amorphous alloy may have the formula (Zr, Ti) a (Ni, Cu) b (Be) c, where each of a, b and c represents weight or atomic percentage. In one embodiment, in atomic percentages, a is in the range of 40 to 75, b is in the range of 5 to 50, and c is in the range of 5 to 50. In addition, the alloy may have the formula (Zr, Ti) a (Ni, Cu) b (Be) c, where each of a, b and c represents weight or atomic percentage. In one embodiment, in atomic percentages, a ranges from 45 to 65, b ranges from 7.5 to 35, and c ranges from 10 to 37.5. Alternatively, the alloy may have the formula (Zr) a (Nb, Ti) b (Ni, Cu) c (Al) d, where each of a, b, c and d is weight or atomic percentage. Represents. In one embodiment, in atomic percentages, a is in the range of 45 to 65, b is in the range of 0 to 10, c is in the range of 20 to 40, and d is in the range of 7.5 to 15. . One exemplary embodiment of the foregoing alloy system is manufactured by Zr-Ti-Ni-Cu-Be-based amorphous alloy under the trade name Vitreloy ™, such as Liquidmetal Technologies, California, USA. Vitreloy-1 and Vitreloy-101. Some examples of different systems of amorphous alloys are provided in Table 1.

  In addition, the amorphous alloy may be an alloy containing iron, such as an (Fe, Ni, Co) based alloy. Examples of such compositions are US Pat. Nos. 6,325,868, 5,288,344, 5,368,659, 5,618,359, and 5,735,975, Inoue et al., Appl. Phys. Lett. 71, p464 (1997), Shen et al., Mater. Trans. , JIM, Vol. 42, p2136 (2001), and Japanese Patent Application No. 200126277 (Japanese Patent Laid-Open No. 2001303218). One exemplary composition is Fe72Al5Ga2P11C6B4. Another example is Fe72Al7Zr10Mo5W2B15. Another iron-based alloy system that can be used for coating herein is disclosed in US Patent Application Publication No. 2010/0084052, where the amorphous metal is, for example, manganese (1 to 3 atomic%), yttrium. (0.1 to 10 atomic%) and silicon (0.3 to 3.1 atomic%) etc. are contained in the range of the composition given in the parenthesis, and the following elements of the composition given in the parenthesis Contain in specified ranges: chromium (15 to 20 atom%), molybdenum (2 to 15 atom%), tungsten (1 to 3 atom%), boron (5 to 16 atom%), carbon (3 to 16 atom) %), And balance iron.

  The amorphous alloy system described above may further contain additional elements, such as additional transition metal elements including Nb, Cr, V, Co, and the like. Additional elements may be present at about 30 wt% or less, such as about 20 wt% or less, such as about 10 wt% or less, such as about 5 wt% or less. In one embodiment, the additional optional element is at least one of cobalt, manganese, zirconium, tantalum, niobium, tungsten, yttrium, titanium, vanadium and hafnium to form carbides, wear and corrosion Further improve the resistance. Further optional elements may lower the melting point by including a total of up to about 2%, preferably less than 1%, of phosphorous acid, germanium and arsenic. Other incidental impurities should be less than about 2%, preferably less than 0.5%.

In some embodiments, a composition having an amorphous alloy can include a small amount of impurities. Impurity elements may be intentionally added to alter the properties of the composition, such as, for example, improving mechanical properties (eg, stiffness, strength, fracture mechanism, etc.) and / or improving corrosion resistance. . Alternatively, impurities may be present as inevitable incidental impurities, such as those obtained as by-products of processing and manufacturing. The impurities may be about 10 wt% or less, such as about 5 wt%, such as about 2 wt%, such as about 1 wt%, such as about 0.5 wt%, such as about 0.1 wt%. In some embodiments, these percentages may be volume percentages instead of weight percentages. In one embodiment, the alloy sample / composition consists essentially of an amorphous alloy (with only incidental minor impurities). In another embodiment, the composition comprises an amorphous alloy (with no observable trace impurities).
Table 1. Exemplary amorphous alloy composition

Melting Instrument One embodiment described herein provides an article or instrument used for elemental alloying and / or melting of metal alloys. In one embodiment, the article may be a container, which in one embodiment may be in the form of a crucible or crucible assembly. The articles described herein can also be used to form and cast metal alloys.

  In one embodiment, the term “alloying” refers to heating a predetermined amount of a plurality of individual “raw” elements (eg, metallic or non-metallic elements) and melting them. Figure 2 shows a process of forming at least one alloy by mixing together. For example, each of these elements may be in the form of a powder, bar, ingot or the like. In some cases, a master alloy that includes an alloy that is at least partially amorphous may be used and alloyed with additional elements. This process, in some embodiments described herein, stacks these elements / master alloys into a particular configuration to soften, melt, wet, and / or other elements with the lowest melting point in the mixture. By fusing with the other elements, the mixture may be disintegrated, mixed, and / or finally homogenized. When the individual components are nearly melted and mixed together, a completely molten and homogeneous alloy product (eg, alloy feedstock) is usually obtained by heating the melt to some predetermined degree. You may definitely get it. The component to be heated and / or mixed (ie, alloying element or alloying element) is sometimes referred to as an “alloy charge”.

  The term “melting” in one embodiment may include the steps described above, but more generally the alloy feedstock (which can be either amorphous or crystalline, and any degree in between. May be used to describe the process of taking an already homogeneous (or relatively homogeneous) piece of crystallinity), heating it above its melting point, and further processing it . In other words, compared to alloying, “melting” herein refers to a homogeneous alloy feed prior to processing in addition to the alloying process (because elements can be alloyed when in the molten state). The process of taking and melting it by heating may be shown. The container used during alloying and / or melting is referred to in some embodiments as a “crucible”.

  The term “molding” in one embodiment described herein may be used interchangeably with “thermoplastic forming” and “hot forming”. Specifically, the term herein may refer to the process of heating the alloy feedstock to a temperature above the glass transition temperature Tg but below the melting temperature Tm and then shaping the shape therefrom. As previously given, the term “feedstock” as used herein may be partially amorphous, substantially amorphous, or completely amorphous. In other words, the forming process in some cases takes place after the melting / alloying process. This is because the former is to mold / form the latter product.

  The term “casting” in one embodiment of the present specification may refer to the process of forming a shape from the molten feedstock after the alloy feedstock has been heated to a temperature above the melting point of the alloy. . The terms “casting” and “forming” may sometimes be used interchangeably. For example, in the case of “injection molding”, the molding process may be similar to the casting process. The container used during alloying and / or melting is called a “mold” in some embodiments.

  The crucible may differ from the mold in several ways. “Crucible” may refer to a container having a cavity, which includes refractory materials used for the manufacture of metals, glass, and pigments, as well as some recent experimental processes, which It can withstand high enough temperatures to melt or otherwise change the contents. The crucible cavity geometry usually has a minimal impact on the final metal / alloy product geometry. This is because the product is often subsequently molded into the desired shape in a separate molding process. In contrast, a “mold” may refer to a hollowed block filled with a liquid such as plastic, glass, metal, or ceramic raw material. The liquid hardens or solidifies in the mold and takes its shape. In other words, the mold cavity geometry may have a significant role on the final metal / alloy product geometry. Because the latter fits the former. Therefore, the design of the mold cavity geometry can be important. In addition, although not true in all cases, generally the alloying / melting process must be performed at a temperature higher than the Tm of the alloy charge, but the forming temperature is not, so The crucible needs to be able to withstand much more heat and impact (eg, attack and contamination as described below) than the mold.

  Articles described herein may include an inner container having a cavity, the inner container including a ceramic, the article may further include an outer container, the outer container including a susceptor, and an outer container. At least a portion of the surface is in contact with the inner surface of the outer container, and the inner container is removable from the mold. In one embodiment, the article may be a crucible or part of a crucible assembly. For example, as shown in FIG. 1, the inner container may be a crucible, which may be placed in the cavity of the outer container.

  The inner container may contain ceramic, may consist essentially of ceramic, or may consist of ceramic. The ceramic may comprise at least one element selected from groups IVA, VA and VIA of the periodic table. Specifically, the element may be at least one of Ti, Zr, Hf, Th, Va, Nb, Ta, Pa, Cr, Mo, W, and U. In one embodiment, the ceramic may comprise an oxide, nitride, oxynitride, boride, carbide, carbonitride, silicate, titanate, silicide, or a combination thereof. For example, ceramics include yttria, silicon nitride, silicon oxynitride, silicon carbide, boron carbonitride, titanium boride (TiB2), zirconium silicate (or “zircon”), aluminum titanate, boron nitride, alumina, zirconia, magnesia, It may include silica, tungsten carbide, aluminum oxynitride (or “sialon”), or a combination thereof. The inner container may include a material that is insensitive to radio frequency (RF) as used in induction heating. One such RF insensitive material is yttria. Alternatively, RF sensitive materials may be used.

  In another embodiment, the inner container may include a refractory material. The refractory material may include a refractory metal such as molybdenum, tungsten, tantalum, niobium, rhenium, for example. Alternatively, the refractory material may include a refractory ceramic. The ceramic may be any of the aforementioned ceramics, including yttria, silicon nitride, silicon carbide, boron nitride, boron carbide, aluminum nitride, alumina, zirconia, titanium diboride, zirconium silicate, aluminum silicate, titanium Includes aluminum acid, tungsten carbide, silica, and fused silica.

  The outer container may include a susceptor. As used herein, “susceptor” may refer to a material used to have the ability to absorb electromagnetic energy and convert it to heat, sometimes so that the heat is re-radiated as infrared thermal radiation. May be designed. This energy may be radio frequency or microwave radiation that is also used in industrial heating processes and sometimes in microwave cooking. Any generally known susceptor may be used. For example, the susceptor may include graphite, refractory material, or both. The refractory material is described above. Alternatively, the susceptor may include silicon carbide, stainless steel, and / or any other conductive material.

  In one embodiment, the outer container may include a material that is more thermally conductive than the material of the inner container. Thus, the outer container can be more thermally conductive than the inner container. The outer container may include a material that is sensitive to RF during induction heating. Alternatively, materials that are insensitive to RF may be used.

  The outer container is connected to a heat source. The heat source may be any suitable heat source. For example, as shown in FIG. 1, the heat source may be an induction heating coil that surrounds at least a portion of the outer container. The inner container 11 is inside the cavity of the outer container 12. In this embodiment, the inner container 11 may be a crucible containing ceramic. The crucible may be any commercially available crucible known in the art suitable for alloying and / or melting. At least a part of the inner container 11 is in contact with the outer container 12. Note that FIG. 1 is merely schematic and alternative versions of designs may exist. For example, the height of 11 may be higher than the height of 12 (as shown), but may be lower or the same height. The wall thickness of the inner container 11 may be the same as, or larger or smaller than, the wall thickness of the outer container 12. The inner and outer containers may have any desired geometry. For example, it may be cylindrical, spherical, cubic, rectangular, or irregularly shaped.

  The outer container and the inner container may be in contact with each other in various ways. For example, in one embodiment, substantially the entire outer surface of the inner container is in contact with the inner surface of the outer container. In one case, the inner container may fit closely within the cavity of the outer container, as shown in the schematic diagram provided in FIG. Depending on the geometry, there may be a gap between the inner and outer containers (as shown at the bottom of the inner container in FIG. 1). Alternatively, the geometry of the two containers may be free of gaps. Thus, the inner and outer containers (as shown in FIG. 1) may be in contact by the entire inner container wall. Alternatively, only certain walls (eg, bottom wall) of the inner container may be in contact with the outer container.

  The inner container may be removed from the outer container and reinserted. In one embodiment, the removable inner container may be reusable. For example, the inner container may be a mold and the molded metal / alloy portion inside the mold may be removed and then the mold may be reinserted into the outer container for subsequent molding processes. This reusability can also be applied when the inner container is used for alloying, melting, or casting. As shown below, the inner container provided here is surprisingly shown to be less wetted by the alloy in contact with it, thereby contaminating the inner surface of the inner container with the metal alloy and vice versa. The risk of being minimized. As a result, the inner crucible can be reused.

  Articles configured as described herein can be used as crucibles (or crucible assemblies) with surprising advantages. For example, the article can allow a crucible containing a thermal shock sensitive material such as yttria or sialon to be used without losing crucible integrity during or after heating. In one embodiment, the inner container may be a crucible containing RF insensitive material. The inner container wall may also serve as a liner for the outer container wall, which may include a susceptor. Thus, instead of an amorphous alloy component in the cavity of the inner container, an RF insensitive material may capture the RF radiation.

  One alternative embodiment provides a crucible assembly that includes an inner layer that includes a ceramic and an outer layer that includes a susceptor, and the susceptor may include carbon (eg, in a form such as graphite). . In one embodiment, at least a portion of the outer surface of the inner layer contacts the inner surface of the outer layer.

  The ceramic of the inner layer may be any shape or size. Instead of being an independent crucible, the inner layer may act as a liner for the susceptor. The inner layer may be a hollow cylinder made of, for example, ceramic sheet or sheets. Alternatively, the inner layer may have a plurality of particulate forms, such as sprayed particulates. The particulates may be sprayed by any known spraying technique. The microparticles may be in the form of particles, and the particles may be any shape or size, such as, for example, a sphere, rod, flake, or any irregular shape. The ceramic may be any of the aforementioned ceramics, such as yttria, silicon nitride, silicon oxynitride, silicon carbide, boron carbonitride, titanium boride, zirconium silicate, aluminum titanate, boron nitride, alumina, zirconia, It may be magnesia, silica, tungsten carbide, or a combination thereof. On the other hand, the outer layer may comprise any of the materials that can be used for the aforementioned outer container.

Melting Process As described above, the articles described herein may be used in melting and / or alloying processes. The melting process in one embodiment includes providing a mixture (or alloy charge) of alloy elements to be alloyed and heating the mixture in a crucible to a temperature above the melting temperature of the alloy elements. But you can. Although the alloy in one embodiment exhibits an at least partially amorphous alloy, the alloy in some cases may also exhibit a crystalline alloy. In one embodiment, the alloy is BMG. The crucible may be any suitable crucible, such as, for example, in any of the articles described herein. In particular, the crucible may be inside the cavity of the outer container. Although crucibles may be used in the molding process, in some of the embodiments provided herein, the crucible is preferably used for melting or molding.

  In one melting embodiment, the mixture may include a plurality of individual alloy elements or at least one master alloy, which are used to make the final alloy composition that can be placed inside the inner vessel, May be heated to a sufficiently high temperature to fuse and melt together to form a molten alloy. The device may be, for example, that shown in FIGS. At least a portion of the heating, for example the entire heating process, may be performed by any of the heating techniques described above, such as induction heating, such as one induction heating performed by an RF frequency. In order to avoid a reaction between the alloy and air, the heating may be carried out under a partial vacuum, for example a low vacuum or a high vacuum. In one embodiment, the vacuum environment may be about 10-2 Torr or less, such as about 10-3 Torr or less, such as about 10-4 Torr or less. Alternatively, the heating and / or disposing step may be performed in an inert atmosphere such as, for example, argon, nitrogen, helium, or mixtures thereof. Non-inert gases such as ambient air may be used if appropriate for the application. In another embodiment, the step may be performed in a combination of partial vacuum and inert atmosphere. In one embodiment, the heating may be performed by vacuum induction melting. Heating may be performed in an inert atmosphere, such as with argon.

  The alloying elements may include metallic elements, non-metallic elements, or both. The element may be any element of the above-described alloy. In addition, after the elements have dissolved together, the alloy is at a temperature above its liquidus temperature, i.e. at a temperature at which it is at least substantially molten, such as the temperature at which the alloy completely melts. It may be held. The length of the period may vary depending on the chemistry of the alloy. As a result, through the crucible provided herein, the element and / or master alloy can be transformed into a homogeneous alloy or alloy feedstock. Additional processing may be applied, including cooling the molten alloying element to a solid feedstock, such as by quenching. The feedstock may be formed into a predetermined geometry that is desirable in a subsequent forming process.

  The mixture is Zr, Fe, Hf, Cu, Co, Ni, Al, Sn, Be, Ti, Pt, Cu, Ni, P, Si, B, Pd, Ag, Ge, Ti, V, Nb, Zr, Be. Fe, C, B, P, Mn, Mo, Cr, Y, Si, Y, Sc, Pb, Mg, Ca, Zn, La, W, Ru, or combinations thereof. Any other element that can be used to form any of the alloys described above may also be used. For example, the alloy may be an amorphous alloy such as BMG. In particular, the alloy may be a noble metal based amorphous alloy comprising Pt, Cu, Ni, P, Si, B, Pd, Ag, Ge, or combinations thereof. The alloy may be a dendritic amorphous alloy comprising Ti, V, Nb, Zr, Be, or combinations thereof. Alternatively, the alloy may be an Fe-based amorphous alloy comprising Fe, C, B, P, Mn, Mo, Cr, Y, or combinations thereof. In addition, the alloy may be any amorphous alloy that includes small additions of Si, Y, Sc, and / or Pb. In addition, the alloy may be one of amorphous alloys including Mg, Ca, Zn, La, W, Ru, or combinations thereof.

  As described above, the inner container desirably includes a material that can minimize wetting between the inner container wall and the alloy feedstock as a result of (or during) the heating process. For example, the inner container may include any of the materials described above as candidates for yttria, sialon, or inner container. The term “wetting” is readily understood in the art. In some embodiments, lack of wetting may also indicate that no significant amount of alloy is observed on the inner wall of the inner container after the molten metal has been quenched and solidified. Good. The presence of alloying elements in the wall can be due to physical interaction / reaction (eg, adsorption) or chemical interaction / reaction (eg, chemical reaction) between the alloy and the inner vessel. In one embodiment, lack of wetting may indicate that there is substantially no alloy on the inner wall of the inner container except for some traces. In addition, the articles described herein can minimize interdiffusion and / or contamination between elements from the alloy and elements throughout the crucible assembly including the inner and / or outer containers. For example, the molten heated alloy charge, and the resulting solid alloy feedstock, may be at least substantially free of elements diffused from the inner vessel, the outer vessel, or both. For example, if the outer layer (or container) includes a graphite susceptor, the alloy may be substantially free of carbon from the graphite susceptor.

  Further, the lack of wetting may be reflected in the absence of reaction (chemical or physical) between the elements of the molten alloy and the elements of the inner vessel (or in some cases the outer vessel). In one embodiment, the articles provided herein may substantially prevent molten alloy charges or individual elements in the inner container from reacting with the inner container at the interface with the inner container. Such a reaction is sometimes referred to as “attack” or alternatively “contamination” against the wall of the crucible of the alloy charge.

  A reaction may refer to various types of reactions. For example, the reaction may indicate that the elements of the inner container are dissolved in the molten alloy, thereby causing contamination of the molten alloy by the constituent elements of the container. Melting may involve the destruction of the crystals that make up the inner vessel and the diffusion of those elements into the molten alloy. In addition, melting may also indicate diffusion of the molten alloy into the inner container. Diffusion may involve alloy (charge) elements being transported diffusively into particles (or crystals) and / or grain boundaries within the container. In some cases, the reaction may indicate that a crystalline phase containing elements from both is produced at the interface between the molten alloy and the inner vessel. These crystal phases may be oxides, nitrides, carbides, etc., and these crystal phases may be intermetallic compounds. They can be carried from the interface to the bulk of the molten alloy by agitation, resulting in further contamination.

  In one embodiment, “attack” (or “contamination”) measures the concentration of impurity elements in the final molten alloy (indicates the extent to which the element including the inner vessel has entered the alloy) or the final molten alloy. May be quantified by any deviation from the desired nominal composition (indicating diffusion of the alloying elements into the inner vessel). This may involve a measurement of the alloy composition and a comparison with the nominal composition for both major components and impurity elements such as oxygen, carbon, nitrogen, sulfur, hydrogen, and inner vessel elements, for example. The tolerance for impurity elements depends on the actual alloy composition to be melted. In addition, one additional measure of “attack” may be the thickness of the inner container wall after processing, which indicates whether a substantial amount of container material has dissolved in the molten alloy. It is.

  Since the inner container is removable from the crucible, the inner container may be removed, cleaned (or subjected to any post-production treatment), and reinserted into the outer container cavity of the crucible. Alternatively, a new replacement inner container may be inserted into the outer container cavity.

  In one embodiment, the inner crucible container may be pretreated. For example, the inside of a crucible such as a crucible containing graphite may be pretreated with a coating of Zr or Si powder, or a compound containing Zr or Si that reacts with carbon. The crucible may then be heated under vacuum to force the powder to react with the crucible to form zirconium carbide or silicon carbide. A pretreated crucible may be used to melt the alloy feedstock, minimizing carbon addition from the graphite to the alloy. In addition to directly using silicon carbide as the ceramic for the inner container, this pretreatment method can be an alternative technique for producing ceramic crucibles with improved thermal shock.

Improved Thermal Shock Resistance As noted above, the articles described herein may have improved thermal shock resistance over existing crucibles when used as a melting instrument. In particular, in one embodiment, by combining an outer container and an inner container (ie, a crucible), the crucible described herein has an improved thermal shock with respect to crack initiation compared to a crucible without an outer container. Has resistance. Measurement of thermal shock resistance can be readily understood by those of ordinary skill in the art. For example, in the case of ceramic, the measurement of thermal shock resistance usually involves slowly heating a solid piece to various high temperatures and then quenching it in a cold medium such as water. The ASTM C1525 standard provides some guidance on this measurement. In one embodiment, the maximum temperature interval at which a solid piece can be quenched without substantially reducing the retained bending strength due to crack induction may represent thermal shock resistance.

  The thermal shock resistance of one material or a combination of various materials can be improved by various techniques. For example, improvements are achieved by using materials with higher thermal conductivity, materials with lower thermal expansion coefficients, materials with higher strength or lower elastic modulus, materials with higher toughness or resistance to cracking The thermal shock resistance may be improved by heating the material more slowly to reduce the thermal gradient of the material itself. In addition, improvements may be achieved by any combination of these techniques, or any other generally known technique.

  In one embodiment, the crucible assembly described herein may improve thermal shock resistance by heating the material more slowly to reduce the thermal gradient of the material itself. Specifically, by using a susceptor on the outside, the inner container may include a material with low thermal shock resistance and / or fracture toughness. The susceptor can uniformly heat the inner container and allows the inner container and the alloy charge therein to be heated slowly and in a more controlled manner, both of which reduce the thermal gradient within the inner container Helps prevent failure due to thermal shock.

  As a result, the articles described herein can effectively prevent cracks into and / or through the walls of the inner container. For example, in one case, no cracks into and / or through the walls of the inner container of the article described herein are observed. For example, existing melting techniques often involve the use of yttria crucibles alone. However, as soon as the alloy charge collapses into the inductively heated crucible, the crucible is immediately cracked by the impact of the molten alloy above about 1000 ° C. hitting the relatively cool crucible. That is, since the crucible is not conductive, it is not heated by induction. FIG. 6 shows the crucible breaking due to thermal shock after heating. In contrast, as provided in the article described herein, as shown in FIG. 7 (c) in one embodiment, if the outside of the crucible is heated through a susceptor, the crucible is before the alloy collapses. The thermal gradient is substantially reduced because it is warmed to near the melting temperature of the inner alloy.

  Because of the high thermal shock resistance that results from the devices described herein, the crucible is in a period of time, such as at least about 1000 ° C., such as at least about 1100 ° C., such as at least about 1200 ° C., such as at least about 1300 ° C. Even after being heated at a high temperature, such as at least about 1400 ° C., such as at least about 1500 ° C., the inner container (or crucible) does not substantially develop observable cracks. The length of the period may vary with temperature, and the length may range from a few minutes to a few hours. For example, the period is at least about 5 minutes, such as at least about 10 minutes, such as at least about 20 minutes, such as at least about 40 minutes, such as at least about 1 hour, such as at least about 2 hours, such as at least about 4 hours, such as at least about 6 The time may be, for example, at least about 8 hours, such as at least about 10 hours, such as at least about 12 hours. In one embodiment, when the temperature is 1200 ° C., substantially no observable cracks are observed over at least 8 hours. In another embodiment, when the temperature is at least about 1300 ° C., such as at least about 1400 ° C., substantially no observable cracks are observed for about 5 minutes to about 60 minutes.

Electronic Device The aforementioned crucible may be used in a fabrication process involving BMG. Because of the superior properties of BMG, BMG can be made into structural components of various devices and components. One such type of device is an electronic device.

  As used herein, an electronic device may refer to any electronic device known in the art. For example, the electronic device may be a telephone, such as a cell phone and landline phone, or any communication device, such as a smartphone including iPhone ™, and an e-mail sending / receiving device. The electronic device may be part of a display such as, for example, a digital display, TV monitor, electronic book reader, portable web browser (eg, iPad ™), and computer monitor. Further, the electronic device may be an entertainment device including a portable DVD player, a conventional DVD player, a Blu-ray disc player, a video game console, a music player, such as a portable music player (eg, iPod ™), and the like. Furthermore, the electronic device may be part of a device that provides control such as, for example, control of image, video, audio streaming (eg, Apple TV ™), or may be a remote control for the electronic device. Good. The electronic device may be part of a computer or its accessories such as a hard drive tower housing or casing, laptop housing, laptop keyboard, laptop trackpad, desktop keyboard, mouse, and speakers, for example. Furthermore, the article may be applied to a device such as a wristwatch or a wall clock.

  In this specification, the articles “a” and “an” are used to indicate that there is one or more (ie at least one) grammatical objects of the article. For example, “a polymer resin” means one polymer resin or two or more polymer resins. All ranges referred to herein are inclusive. As used throughout this specification, the terms “substantially” and “about” are used to describe and explain small variations. For example, the terms are ± 5% or less, such as ± 2% or less, such as ± 1% or less, such as ± 0.5% or less, such as ± 0.2% or less, such as ± 0.1% or less, such as ± 0. .05% or less may be indicated.

Non-limiting Examples A series of experiments were conducted to test the level of contamination in various crucible materials.

Yttria This ceramic was found to wet LM1 weakly, and chemical analysis showed that contaminant levels were acceptable (low) even after 1 hour of substantial overheating. Furthermore, in the absence of an outer container containing a susceptor, the thermal shock resistance of yttria was very low and it was found that the crucible cracked as soon as the molten alloy collapsed.

  An alternative yttria crucible embodiment was tested. Yttria was spray coated on the inside of the graphite crucible for melting the Hf-based amorphous alloy. The yttria coating was baked at 1200 ° C. for 8 hours before introducing the alloy. After the melting process, surprisingly no alloy wetting and no attack on the graphite were observed.

Sialon Sialon, a variation of silicon nitride, is generally a ceramic with fairly good thermal shock resistance and toughness. Experimental results show that sialon can resist wetting and attack by most molten alloys in contact during the experiment. Nitrogen levels were found to increase only slightly and sialon was determined to be a desirable material for processing Zr-based alloys.

Silicon Carbide Silicon carbide was used as a porous filter material to reduce the amount of dross in the feedstock. Multiple castings of various alloys were made with SiC, and it was generally observed that Zr-based alloys wet the material very weakly or not at all. Silicon carbide has been determined to be a good candidate for alloy melting to reduce contamination. In order to reduce thermal shock, it has been proposed to place a silicon carbide crucible inside the graphite susceptor as described above.

  FIG. 2 provides a photograph of an experimental apparatus for testing the compatibility of sialon and Zr-based amorphous alloys. The crucible 21 is placed inside the quartz housing 22 that is evacuated to less than 0.005 Torr, and an induction coil 23 is placed around the outside of the exhaust quartz housing, the sialon crucible, and the alloy ingot in the crucible. It was. As shown in FIG. 3, the top hose 31 is connected to a vacuum pump, and the coil 23 is connected to an RF power source.

  4 (a) -4 (b) provide photographs showing the ingot being inductively melted in a sialon at 1000 ° C. for about 30 minutes and the alloy cooled to room temperature. The crucible was then intentionally broken to assess whether the alloy was wet and bonded to sialon. In practice, the alloy went completely out of the sialon, leaving no residue in the original crucible. This indicates very low wetting, i.e. good suitability for alloy processing. FIG. 5 provides a photograph showing that a large amount of copper has evaporated from the alloy in 30 minutes, and the same copper deposition was observed when the boat was lined with a sialon sleeve.

  The yttria crucible was heated with a zirconium base alloy at 1000 ° C. for 1 hour and then slowly cooled. FIG. 6 provides a photograph showing that the top of the crucible was destroyed after the alloy was rapidly heated, melted and filled into the crucible. The alloy was slowly cooled and held in a cracked crucible. However, the wetness between the alloy and the crucible was low and it was fairly easy to remove the crucible fragments, indicating good suitability for processing.

As shown by chemical analysis, the contamination is low and the results are provided in Table 2. Yttria is shown to have slightly increased O content compared to graphite. This result indicates that the tested ceramic crucible may have low wetting due to alloy charge. Thus, by introducing the outer container of the c susceptor, the entire crucible assembly will benefit from low wetting and improved thermal shock resistance.
Table 2. Chemical analysis results showing different contamination levels for different crucible designs.

  For comparison, the following experiment was performed using the yttria crucible 71 in the graphite susceptor 72. Both were held inside the quartz container 73 as shown in FIGS. 7 (a) -7 (c).

  The alloy ingot placed in the yttria crucible is a Zr—Ti—Cu—Ni—Be base alloy (LM1), the composition of which is shown in Table 2. The susceptor was inductively heated to melt the alloy ingot, and the alloy ingot collapsed into the yttria crucible. The alloy was held at about 1000 ° C. for 1 hour and then slowly cooled to room temperature. As the alloy melted and filled the crucible, it was observed that the yttria crucible was uniformly heated by radiation from the graphite susceptor, and no cracks (due to thermal shock) were observed in the crucible. Please refer to FIGS. 7 (b) to 7 (c).

Claims (26)

Goods,
An inner container having a cavity and a thermal shock sensitive ceramic;
An outer container,
At least a portion of the outer surface of the inner container is in contact with the inner surface of the outer container;
The inner container is reusable and removable from the outer container;
The article has improved thermal shock resistance with respect to crack initiation as compared to a similar article without the outer container.   The article of claim 1, wherein the ceramic comprises at least one element selected from groups IVA, VA, and VIA of the periodic table of elements.   The article of claim 1, wherein the ceramic comprises an oxide, nitride, oxynitride, boride, carbide, carbonitride, silicate, titanate, silicide, or a combination thereof.   The ceramic is yttria, silicon nitride, silicon oxynitride, silicon carbide, boron carbonitride, titanium boride, zirconium silicate, aluminum titanate, boron nitride, alumina, zirconia, magnesia, silica, tungsten carbide, aluminum oxynitride The article of claim 1 comprising a combination thereof.   The article of claim 1, wherein the outer container comprises graphite, refractory material, silicon carbide, or a combination thereof.   The article of claim 1, wherein at least one of the inner container and the outer container comprises a refractory material.   The article of claim 1, wherein the outer container has a higher thermal conductivity than the inner container.   The article of claim 1, wherein the outer container is connected to a heat source.   The article of claim 1, wherein substantially the entire outer surface of the inner container contacts the inner surface of the outer container.   The article of claim 1, wherein the removable inner container is reusable. A melting method,
Providing a mixture of alloying elements;
Heating the mixture to a temperature above the melting temperature of the alloying element in an article, and
The article is
An inner container having a cavity containing the mixture and comprising a ceramic;
An outer container,
At least a portion of the outer surface of the inner container is in contact with the inner surface of the outer container;
The method, wherein the inner container is removable from the article.   The ceramic is yttria, silicon nitride, silicon oxynitride, silicon carbide, boron carbonitride, titanium boride, zirconium silicate, aluminum titanate, boron nitride, alumina, zirconia, magnesia, silica, tungsten carbide, aluminum oxynitride 12. The method of claim 11, comprising a combination thereof.   The alloy elements are Zr, Fe, Hf, Cu, Co, Ni, Al, Sn, Be, Ti, Pt, Cu, Ni, P, Si, B, Pd, Ag, Ge, Ti, V, Nb, Zr. 12, comprising: Be, Fe, C, B, P, Mn, Mo, Cr, Y, Si, Y, Sc, Pb, Mg, Ca, Zn, La, W, Ru, or combinations thereof. Method.   The method of claim 11, wherein at least a portion of the heating step is performed by vacuum induction melting.   The method of claim 11, further comprising quenching the molten alloy element in the mixture to form an at least partially amorphous composition.   The method of claim 11, wherein substantially no wetting occurs between the inner container and the heated mixture after the heating step.   The method of claim 11, further comprising removing the inner container and reinserting the inner container into the article.   The method of claim 11, wherein the heated mixture is substantially free of elements from the outer container.   The method of claim 11, wherein the inner container has improved thermal shock resistance with respect to crack initiation compared to an inner container that does not have an outer container.   The method of claim 11, wherein the inner container is substantially free of observable cracks after the article is heated at 1200 ° C. for at least 8 hours. A crucible assembly,
An inner layer comprising ceramic;
An outer layer comprising carbon,
At least a portion of the outer surface of the inner layer is in contact with the inner surface of the outer layer;
The crucible assembly, wherein the crucible has improved thermal shock resistance with respect to crack initiation compared to a similar crucible without the outer container.   The inner layer is yttria, silicon nitride, silicon oxynitride, silicon carbide, boron carbonitride, titanium boride, zirconium silicate, aluminum titanate, boron nitride, alumina, zirconia, magnesia, silica, tungsten carbide, aluminum oxynitride The crucible assembly of claim 21 comprising particles comprising an article, or a combination thereof.   The crucible assembly of claim 21, wherein the outer layer comprises graphite.   The crucible assembly of claim 21, wherein the inner layer is part of a crucible.   The crucible assembly of claim 21, wherein the ceramic comprises sprayed particulates.   The article of claim 1, wherein the ceramic includes at least one element selected from Ti, Zr, Hf, Th, Va, Nb, Ta, Pa, Cr, Mo, W, and U.