A method for joining engine components includes positioning a first plurality of thermal protection structures across a thermal protection space between a first thermal protection surface and a second thermal protection surface. The first and second engine components are locally joined by forming a first plurality of transient liquid phase (TLP) or partial transient liquid phase (PTLP) bonds along corresponding ones of the first plurality of thermal protection structures between the first thermal protection surface and the second thermal protection surface. The second thermal protection surface is formed from a second surface material different from a first surface material of the first thermal protection surface.

Provided is a metal powder sintering paste having a high resistance to thermal stress. The present invention provides a metal powder sintering paste containing silver particles having an average particle diameter (median diameter) of 0.3 m to 5 m as a main component, further containing inorganic spacer particles having a CV value (standard deviation/average value) of less than 5%, and containing substantially no resin.

A pressure measurement cell, comprising: a ceramic measurement membrane and a ceramic counterpart. The measurement membrane is joined to the counterpart in a pressure-tight manner forming a pressure chamber between the measurement membrane and the counterpart by means of an active brazing solder. The pressure measurement cell furthermore has a solder stop layer on a surface of the measurement membrane and/or the counterpart, wherein the solder stop layer has a metal oxide or a reduced form of the metal oxide. The metal oxide has at least one oxidation stage, which, assuming an activity coefficient of R.sub.akt=1 at an inverse temperature of 8.Math.10.sup.4/K, has an oxygen coexistence decomposition pressure of not less than 1.sup.23 MPa (10.sup.23.Math. bar) and not more than 1.sup.12 MPa (10.sup.12.Math. bar) and which, assuming an activity coefficient of R.sub.akt=1, at an inverse temperature of 9.Math.10.sup.4/K has an oxygen coexistence decomposition pressure of not less than 1.sup.27 MPa (10.sup.27 bar) and not more than 1.sup.15 MPa (10.sup.15 bar). Suitable metal oxides are, for example, oxides of chromium, tungsten or titanium.

Provided is a metal powder sintering paste having a high resistance to thermal stress. The present invention provides a metal powder sintering paste containing silver particles having an average particle diameter (median diameter) of 0.3 m to 5 m as a main component, further containing inorganic spacer particles having a CV value (standard deviation/average value) of less than 5%, and containing substantially no resin.

The invention described herein pertains generally to boric acid free flux composition wherein in some embodiments, a phthalocyanine pigment is used to effect a color change at activation temperature.

A universal approach is described to produce welding filler materials with enhanced grain refining, for making welded objects with hot-crack resistance. Some variations provide a welding filler material comprising a functionalized metal-containing powder, wherein the functionalized metal-containing powder comprises metal or metal alloy particles and a plurality of nanoparticles disposed on surfaces of the metal or metal alloy particles, and wherein the nanoparticles are consolidated in a three-dimensional architecture throughout the welding filler material. A welded object contains a welding filler material comprising the functionalized metal-containing powder, enabling the welded object to be free of hot cracks. Other variations provide methods of making a welding filler material. This approach has been successfully demonstrated by incorporating zirconium-based nanoparticle grain refiners within a welding precursor material for welding aluminum alloy Al 7075, as one non-limiting example.

A method of fabricating a joining preform includes the step of printing a self-fluxing joining alloy. Joining includes brazing and soldering. The self-fluxing joining alloy contains at least one of phosphorus, boron, fluorine, chlorine, or potassium. Another printing step prints a non-phosphorous joining alloy. Both printing steps are performed by an additive manufacturing or 3D printing process. The printing a self-fluxing joining alloy step may be repeated until the non-phosphorous joining alloy is substantially encapsulated by the self-fluxing joining alloy. The self-fluxing joining alloy may be a BCuP alloy, a CuP alloy, a CuSnP alloy, a CuSnNiP alloy or a CuAgP alloy. The non-phosphorous joining alloy may be a BAg alloy, a BNi alloy or a BAu alloy.

A solder alloy substantially consists of tin, silver, indium, bismuth, and antimony. With respect to the total amount of the solder alloy, the content ratio of the silver is 2.8 mass % or more and 4 mass % or less; the content ratio of the indium is 6.2 mass % or more and 9.0 mass % or less; the content ratio of the bismuth is 0.7 mass % or more and 5.0 mass % or less; the content ratio of the antimony is 0.3 mass % or more and 5.0 mass % or less; and the content ratio of the tin is the remaining ratio and the value of A is 4.36 or less wherein A=0.87[In content ratio (mass %)]0.41[Ag content ratio (mass %)]0.82[Sb content ratio (mass %)].

A solder alloy is a tin-silver-copper solder alloy substantially consisting of tin, silver, copper, bismuth, nickel, cobalt, and indium. With respect to the total amount of the solder alloy, the content ratio of the silver is 2 mass % or more and 5 mass % or less; the content ratio of the copper is 0.1 mass % or more and 1 mass % or less; the content ratio of the bismuth is 0.5 mass % or more and 4.8 mass % or less; the content ratio of the nickel is 0.01 mass % or more and 0.15 mass % or less; the content ratio of the cobalt is 0.001 mass % or more and 0.008 mass % or less; the content ratio of the indium is above 6.2 mass % and 10 mass % or less; and the content ratio of the tin is the remaining ratio.

The invention described herein pertains generally to boric acid free flux composition in which boric acid and/or borax is substituted with a molar equivalent amount of potassium tetraborate tetrahydrate. In some embodiments, a phthalocyanine pigment is used to effect a color change at activation temperature.