A sintered body includes a crystal grain containing silicon nitride, and a grain boundary phase. If dielectric losses of the sintered body are measured while applying an alternating voltage to the sintered body and continuously changing a frequency of the alternating voltage from 50 Hz to 1 MHz, an average value .sub.A of dielectric losses of the sintered body in a frequency band from 800 kHz to 1 MHz and an average value .sub.B of dielectric losses of the sintered body in a frequency band from 100 Hz to 200 Hz satisfy an expression |.sub.A.sub.B|0.1.

The present invention is a bonded body in which an aluminum member constituted by an aluminum alloy, and a metal member constituted by copper, nickel, or silver are bonded to each other. The aluminum member is constituted by an aluminum alloy in which a solidus temperature is set to be less than a eutectic temperature of a metal element that constitutes the metal member and aluminum. A Ti layer is formed at a bonding portion between the aluminum member and the metal member, and the aluminum member and the Ti layer, and the Ti layer and the metal member are respectively subjected to solid-phase diffusion bonding.

To improve a TCT characteristic of a circuit substrate. The circuit substrate comprises a ceramic substrate including a first and second surfaces, and first and second metal plates respectively bonded to the first and second surfaces via first and second bonding layers. A three-point bending strength of the ceramic substrate is 500 MPa or more. At least one of L1/H1 of a first protruding portion of the first bonding layer and L2/H2 of a second protruding portion of the second bonding layer is 0.5 or more and 3.0 or less. At least one of an average value of first Vickers hardnesses of 10 places of the first protruding portion and an average value of second Vickers hardnesses of 10 places of the second protruding portion is 250 or less.

A joined body according to the invention is a ceramic/aluminum joined body including: a ceramic member; and an aluminum member made of aluminum or an aluminum alloy, in which the ceramic member and the aluminum member are joined to each other, the ceramic member is formed of silicon nitride containing magnesium, and a joining layer in which magnesium is contained in an aluminum-silicon-oxygen-nitrogen compound is formed at a joining interface between the ceramic member and the aluminum member.

The disclosure describes techniques for forming a surface layer of an article including a CMC using a cast. In some examples, the surface layer includes three-dimensional surface features, which may increase adhesion between the CMC and a coating on the CMC. In some examples, the surface layer may include excess material, with or without three-dimensional surface features, which is on the CMC. The excess material may be machined to remove some of the excess material and facilitate conforming the article to dimensional tolerances, e.g., for fitting the article to another component. The excess material may reduce a likelihood that the CMC (e.g., reinforcement material in the CMC) is damaged by the machining.

To improve a TCT characteristic of a circuit substrate. The circuit substrate comprises a ceramic substrate including a first and second surfaces, and first and second metal plates respectively bonded to the first and second surfaces via first and second bonding layers. A three-point bending strength of the ceramic substrate is 500 MPa or more. At least one of L1/H1 of a first protruding portion of the first bonding layer and L2/H2 of a second protruding portion of the second bonding layer is 0.5 or more and 3.0 or less. At least one of an average value of first Vickers hardnesses of 10 places of the first protruding portion and an average value of second Vickers hardnesses of 10 places of the second protruding portion is 250 or less.

A bonded body is provided that is formed by bonding a metal member formed from copper, nickel, or silver, and an aluminum alloy member formed from an aluminum alloy of which a solidus temperature is lower than a eutectic temperature of aluminum and a metal element that constitutes the metal member. The aluminum alloy member and the metal member are subjected to solid-phase diffusion bonding. A chill layer, in which a Si phase of which an aspect ratio of a crystal grain is 2.5 or less and a crystal grain diameter is 15 m or less is dispersed, is formed on a bonding interface side with the metal member in the aluminum alloy member. The thickness of the chill layer is set to 50 m or greater.

Provided is a heat-sink-attached power-module substrate, in which a metal layer and first layers are formed from aluminum sheets having a purity of 99.99 mass % or greater and a heat sink and second layers are formed from aluminum sheets having a purity lower than that of the metal layer and the first layers: when a thickness is t1 (mm), a joined-surface area is A1 (mm2), yield strength at 25 C. is 11 (N/mm2), yield strength at 200 C. is 12 (N/mm2) in the second layers; a thickness is t2 (mm), a joined-surface area is A2 (mm2), yield strength at 25 C. is 21 (N/mm2), and yield strength at 200 C. is 22 (N/mm2) in the heat sink.

A method for the joining of ceramic pieces with a hermetically sealed joint comprising brazing a layer of joining material between the two pieces. The ceramic pieces may be aluminum nitride or other ceramics, and the pieces may be brazed with Nickel and an alloying element, under controlled atmosphere. The completed joint will be fully or substantially Nickel with another element in solution. The joint material is adapted to later withstand both the environments within a process chamber during substrate processing, and the oxygenated atmosphere which may be seen within the interior of a heater or electrostatic chuck. Semiconductor processing equipment comprising ceramic and joined with a nickel alloy and adapted to withstand processing chemistries, such as fluorine chemistries, as well as high temperatures.

In an aluminum material that constitutes a bonding surface of a metal layer, and an aluminum material that constitutes a bonding surface of a heat sink, any one aluminum material is set to a high-purity aluminum material with high aluminum purity, and the other aluminum material is set to a low-purity aluminum material with low aluminum purity. The difference in a concentration of a contained element other than Al between the high-purity aluminum material and the low-purity aluminum material is set to 1 at % or greater, and the metal layer and the heat sink are subjected to solid-phase diffusion bonding.