The present invention discloses an Al.sub.2O.sub.3-based ceramic welding sealing component and a preparation method thereof, and relates to the technical field of metalized ceramic processing. The Al.sub.2O.sub.3-based ceramic welding sealing component disclosed in the present invention comprises a ceramic matrix and a metallized layer. The ceramic matrix is made from raw materials such as an inorganic fiber-aluminum oxide 3D network matrix, yttrium oxide, silicon oxide, titanium oxide, an additive, a binder and a dispersant, through steps such as preparation of the inorganic fiber-aluminum oxide 3D network matrix, mixing, pelletizing, primary sintering and secondary sintering; and the raw materials of the metallized layer comprise titanium powder, tungsten powder, molybdenum oxide, boron oxide, yttrium oxide and an organic binder. Al.sub.2O.sub.3-based ceramic welding sealing component provided by the present invention has high efficiency of space filling and tensile strength, excellent tensile strength, toughness and high-temperature resistance.

A method of forming a ceramic matrix composite with being impregnated with molten metal includes: stacking a plurality of fiber layers that are layers of reinforced fibers impregnated with base resin to form a laminate in which a matrix layer containing fibers extending in a direction of impregnation with the molten metal is disposed between the fiber layers; forming an impregnation path in the matrix layer entirely in an in-plane direction perpendicular to a direction of the stacking in the laminate by carbonizing the formed laminate; and impregnating, with the molten metal, the laminate in which the impregnation path has been formed.

A method of forming a ceramic matrix composite with being impregnated with molten metal includes: stacking a plurality of fiber layers that are layers of reinforced fibers impregnated with base resin to form a laminate in which a matrix layer containing fibers extending in a direction of impregnation with the molten metal is disposed between the fiber layers; forming an impregnation path in the matrix layer entirely in an in-plane direction perpendicular to a direction of the stacking in the laminate by carbonizing the formed laminate; and impregnating, with the molten metal, the laminate in which the impregnation path has been formed.

A heating element and method for fabricating the same includes: a heating material piece configured to generate heat when being powered. A first substrate is configured to support the heating material piece and a liquid guiding member is configured to guide an atomizing liquid to be heated. The first substrate is a substrate made of a dense material and the heating material piece is a film with a certain resistance formed by a resistive slurry fixed on a surface of the dense material substrate by at least one selected from printing, coating, soaking and spraying. Two wires are electrically connected to the first substrate to form electrodes that are respectively connected to two ends of the film with a certain resistance. The liquid guiding member is a member made of a microporous material fixed outside the first substrate and the heating material piece.

Among two main surfaces of a heat dissipation member, one main surface is curved to be convex in an outward direction and the other convex in an inward direction. When a straight line passing through both endpoints P.sub.1 and P.sub.2 of the curve is l.sub.1, a point at which a distance to l.sub.1 on the curve is maximum is P.sub.max, an intersection point between l.sub.1 and a perpendicular drawn from P.sub.max to l.sub.1 is P.sub.3, a middle point of a line segment P.sub.1P.sub.3 is P.sub.4, an intersection point between the curve and a straight line that passes through P.sub.4 and is perpendicular to l.sub.1 is P.sub.mid, a length of the line segment P.sub.1P.sub.3 is L, a length of a line segment P.sub.3P.sub.max is H, and a length of a line segment P.sub.4P.sub.max is h, (2 h/L)/(H/L) is 1.1 or more.

Among two main surfaces of a heat dissipation member, one main surface is curved to be convex in an outward direction and the other convex in an inward direction. When a straight line passing through both endpoints P.sub.1 and P.sub.2 of the curve is l.sub.1, a point at which a distance to l.sub.1 on the curve is maximum is P.sub.max, an intersection point between l.sub.1 and a perpendicular drawn from P.sub.max to l.sub.1 is P.sub.3, a middle point of a line segment P.sub.1P.sub.3 is P.sub.4, an intersection point between the curve and a straight line that passes through P.sub.4 and is perpendicular to l.sub.1 is P.sub.mid, a length of the line segment P.sub.1P.sub.3 is L, a length of a line segment P.sub.3P.sub.max is H, and a length of a line segment P.sub.4P.sub.max is h, (2 h/L)/(H/L) is 1.1 or more.

A copper-ceramic composite: includes a ceramic substrate containing alumina and a copper or copper alloy coating on the ceramic substrate. The alumina has a mean grain shape factor R.sub.a(Al.sub.2O.sub.3), defined as the arithmetic mean of the shape factors R of the alumina grains, of at least 0.4.

A copper-ceramic composite: includes a ceramic substrate containing alumina and a copper or copper alloy coating on the ceramic substrate. The alumina has a mean grain shape factor R.sub.a(Al.sub.2O.sub.3), defined as the arithmetic mean of the shape factors R of the alumina grains, of at least 0.4.

There is provided a group III nitride laminate, including: a substrate comprised of silicon carbide; a first layer comprised of aluminum nitride and formed on the substrate; a second layer comprised of gallium nitride and formed on the first layer; and a third layer formed on the second layer and comprised of group III nitride having an electron affinity lower than that of the gallium nitride which is comprised in the second layer, the second layer having a thickness of less than 500 nm, the second layer containing iron at a concentration of less than 1×10.sup.17/cm.sup.3, and the second layer containing carbon at a concentration of less than 1×10.sup.17/cm.sup.3.

There is provided a group III nitride laminate, including: a substrate comprised of silicon carbide; a first layer comprised of aluminum nitride and formed on the substrate; a second layer comprised of gallium nitride and formed on the first layer; and a third layer formed on the second layer and comprised of group III nitride having an electron affinity lower than that of the gallium nitride which is comprised in the second layer, the second layer having a thickness of less than 500 nm, the second layer containing iron at a concentration of less than 1×10.sup.17/cm.sup.3, and the second layer containing carbon at a concentration of less than 1×10.sup.17/cm.sup.3.