Organosilicon chemistry, polymer derived ceramic materials, and methods. Such materials and methods for making polysilocarb (SiOC) and Silicon Carbide (SiC) materials having 3-nines, 4-nines, 6-nines and greater purity. Processes and articles utilizing such high purity SiOC and SiC.

In a case where a detector is positioned in a [11-20] direction, and where a first measurement region including a center of a main surface is irradiated with an X ray in a direction within ±15° relative to a [−1-120] direction, a ratio of a maximum intensity of a first intensity profile is more than or equal to 1500. In a case where the detector is positioned in a direction parallel to a [−1100] direction, and where the first measurement region is irradiated with an X ray in a direction within ±6° relative to a [1-100] direction, a ratio of a maximum intensity of a second intensity profile is more than or equal to 1500. An absolute value of a difference between maximum value and minimum value of energy at which the first intensity profile indicates a maximum value is less than or equal to 0.06 keV.

An additive manufacturing method of producing a metal alloy article may involve: Providing a supply of a metal alloy in powder form; providing a supply of a nucleant material, the nucleant material lowering the nucleation energy required to crystallize the metal alloy; blending the supply of metal alloy powder and nucleant material to form a blended mixture; forming the blended mixture into a first layer; subjecting at least a portion of the first layer to energy sufficient to raise the temperature of the first layer to at least the liquidus temperature of the metal alloy; allowing at least a portion of the first layer to cool to a temperature sufficient to allow the metal alloy to recrystallize; forming a second layer of the blended mixture on the first layer; and repeating the subjecting and allowing steps on the second layer to form an additional portion of the metal alloy article.

An additive manufacturing method of producing a metal alloy article may involve: Providing a supply of a metal alloy in powder form; providing a supply of a nucleant material, the nucleant material lowering the nucleation energy required to crystallize the metal alloy; blending the supply of metal alloy powder and nucleant material to form a blended mixture; forming the blended mixture into a first layer; subjecting at least a portion of the first layer to energy sufficient to raise the temperature of the first layer to at least the liquidus temperature of the metal alloy; allowing at least a portion of the first layer to cool to a temperature sufficient to allow the metal alloy to recrystallize; forming a second layer of the blended mixture on the first layer; and repeating the subjecting and allowing steps on the second layer to form an additional portion of the metal alloy article.

A method for fabricating a component according to an example of the present disclosure includes the steps of depositing a stoichiometric precursor layer onto a preform, and densifying the preform by depositing a matrix material onto the stoichiometric precursor layer. An alternate method and a component are also disclosed.

A technology for securing favorable appearance of a SiC member, the SiC member includes: a first SiC layer having a first upper surface having a concavo-convex shape and a first lower surface; and a second SiC layer having a second upper surface and a second lower surface, the second lower surface being in contact with the first upper surface and having a concavo-convex shape corresponding to that of the first upper surface. The second SiC layer has a recess concaved from the second upper surface toward the second lower surface side and a flat bottom surface, and the bottom surface of the recess is placed upward of the second lower surface.

A technology for securing favorable appearance of a SiC member, the SiC member includes: a first SiC layer having a first upper surface having a concavo-convex shape and a first lower surface; and a second SiC layer having a second upper surface and a second lower surface, the second lower surface being in contact with the first upper surface and having a concavo-convex shape corresponding to that of the first upper surface. The second SiC layer has a recess concaved from the second upper surface toward the second lower surface side and a flat bottom surface, and the bottom surface of the recess is placed upward of the second lower surface.

The disclosure provides a silicon carbide seed crystal and a method of manufacturing a silicon carbide ingot. The silicon carbide seed crystal has a silicon surface and a carbon surface opposite to the silicon surface. A difference D between a basal plane dislocation density BPD1 of the silicon surface and a basal plane dislocation density BPD2 of the carbon surface satisfies the following formula (1), a local thickness variation (LTV) of the silicon carbide seed crystal is 2.5 μm or less, and a stacking fault (SF) density of the silicon carbide seed crystal is 10 EA/cm.sup.2 or less:

D=(BPD1−BPD2)/BPD1≤25%  (1).

There is provided a silicon carbide powder having a small mean particle diameter and a narrow particle diameter distribution width. A silicon carbide powder is a powder of silicon carbide (SiC) having an α-type crystal form and has a mean particle diameter of 300 nm or less. In the silicon carbide powder, a ratio D90/D10 between a particle diameter D10 and a particle diameter D90 is 4 or less, the particle diameter D10 being a particle diameter at which the cumulative particle volume from the small particle diameter side in a volume-based cumulative particle diameter distribution reaches 10% of the total particle volume and the particle diameter D90 being a particle diameter at which the cumulative particle volume from the small particle diameter side in the volume-based cumulative particle diameter distribution reaches 90% of the total particle volume.

A SiC ingot includes: a main body including a first cross-sectional plane of the main body and a second cross-sectional plane of the main body facing the first cross-sectional plane; and a protrusion disposed on the second cross-sectional plane and including a convex surface from the second cross-sectional plane of the main body, wherein a first end point disposed at one end of the second cross sectional plane, a second end point disposed at another end of the second cross sectional plane, and a peak point disposed on the convex surface are disposed on a third cross-sectional plane of the main body perpendicular to the first cross-sectional plane, and wherein a radius of curvature of an arc corresponding to a line of intersection between the third cross-sectional plane and the convex surface satisfies Equation 1 below:
3D≤r≤37D  [Equation 1]
where r is the radius of curvature of the arc corresponding to the line of intersection between the third cross-sectional plane and the convex surface, and D is a length of a line of intersection between the first cross-sectional plane and the third cross-sectional plane.