An amorphous ductile brazing foil is provided. The brazing foil has a composition consisting substantially of Ni.sub.BalCr.sub.aB.sub.b,P.sub.cSi.sub.dMo.sub.eX.sub.fY.sub.g, with 21 atomic %a28 atomic %; 0.5 atomic %b7 atomic %; 4 atomic %c12 atomic %; 2 atomic %d10 atomic %; 0 atomic %<e5 atomic %; 0 atomic %f5 atomic %; 0 atomic %g20 atomic %; incidental impurities1.0 atomic %; balance Ni, wherein X is one or more of the elements Nb, Ta, W, Cu, C or Mn and Y is one or both of the elements Fe and Co and a/c2.

A method for producing a reinforced alloy powder containing a metal matrix in which crystalline oxide particles are dispersed, including: (i) providing a powder mixture including a parent metal powder including a master alloy for forming the metal matrix and an additional powder including an intermediate; (ii) milling the powder mixture by a mechanical synthesis process to make a precursor powder; and (iii) subjecting the precursor powder to a thermal plasma generated by a plasma torch including a plasma gas. The master alloy is iron-based, nickel-based, or aluminum-based. The intermediate is at least one of YFe.sub.3, Y.sub.2O.sub.3, Fe.sub.2O.sub.3, Fe.sub.2Ti, FeCrWTi, TiH.sub.2, TiO.sub.2, Al.sub.2O.sub.3, HfO.sub.2, SiO.sub.2, ZrO.sub.2, ThO.sub.2, and MgO. In (iii), the precursor powder is injected into the plasma torch at a flow rate of 10-30 g/min, a power of the plasma torch is 20-40 kW, and a pressure in a reaction chamber of the plasma torch is 25-100 kPa.

Disclosed is a semi-amorphous, ductile brazing foil with a composition consisting essentially of Ni.sub.balFe.sub.aCr.sub.bP.sub.cSi.sub.dB.sub.eMo.sub.f with approximately 30 atomic percentaapproximately 38 atomic percent; approximately 10 atomic percentbapproximately 20 atomic percent; approximately 7 atomic percentcapproximately 20 atomic percent; approximately 2 atomic percentdapproximately 4 atomic percent; eapproximately 2 atomic percent; fapproximately 5 atomic percent; and the balance being Ni and other impurities; where c+d+e<approximately 16 atomic percent.

An object of the present invention is to provide an Ni-based alloy pipe or tube for nuclear power with reduced rate of SCC crack propagation. The Ni-based alloy pipe or tube for nuclear power according to the present invention is an Ni-based alloy pipe or tube having a wall thickness of 15 to 55 mm, having a chemical composition of, in mass %: 0.010 to 0.025% C; 0.10 to 0.50% Si; 0.01 to 0.50% Mn; up to 0.030% P; up to 0.002% 5;52.5 to 65.0% Ni; 20.0 to 35.0% Cr; 0.03 to 0.30% Mo; up to 0.018% Co; up to 0.015% Sn; 0.005 to 0.050% N; 0 to 0.300% Ti; 0 to 0.200% Nb; 0 to 0.300% Ta; 0% or more and less than 0.03% Zr; and the balance being Fe and impurities, wherein the Ni-based alloy pipe or tube has a microstructure being an austenite single phase, and the chemical composition satisfies the following equation, Eq. (1):

0.0020[N]/14{[Ti]/47.9+[Nb]/92.9+[Ta]/180.9+[Zr]/91.2}0.0015 Eq. (1).

For the element symbols in Eq. (1), the contents of the corresponding elements in mass % are substituted.

The contents of Cr, Fe, Mn, Ti, Si, Cu, N, Al, C, Mg, Mo, B, Zr, and Nb+Ta in a Ni-base alloy weld metal are properly specified and the contents of Co, P, and S in incidental impurities are controlled. In particular, a weld metal having high cracking resistance is formed by specifying the Mn content in a proper range and restricting the contents of B and Zr at low levels. Regarding a Ni-base alloy covered electrode, by specifying the contents of a slag-forming agent, a metal fluoride, and a carbonate serving as flux components in proper ranges and controlling the contents of Mn, Nb+Ta, and Fe in a flux, good welding workability is achieved and a weld metal having good bead appearance is formed.

The erosion-prone sections of the tubes in a circulating fluidized bed boiler are provided with a locally thickened sidewall without forming discontinuities on the outer surface of the tubes. This can be accomplished, for example, by replacing the erosion prone portion of the tube with a section having a smaller inside diameter, but the same outside diameter, or by replacing the erosion prone portion of the tube with a section having a thicker sidewall, but the same inside diameter, and smoothing over the outside discontinuity with an alloy coating. A useful alloy coating is also disclosed which can be used for this and other applications.

A nickel-chromium-molybdenum-copper alloy resistant to 70% sulfuric acid at 93 C. and 50% sodium hydroxide at 121 C. for acid and alkali neutralization in the field of waste management; the alloy contains, in weight percent, 27 to 33 chromium, 4.9 to 7.8 molybdenum, 3.1 to 6.0 wt. % copper (when chromium is between 30 and 33 wt. %) or 4.7 to 6.0 wt. % copper (when chromium is between 27 and 29.9 wt. %), up to 3.0 iron, 0.3 to 1.0 manganese, 0.1 to 0.5 aluminum, 0.1 to 0.8 silicon, 0.01 to 0.11 carbon, up to 0.13 nitrogen, up to 0.05 magnesium, up to 0.05 rare earth elements, with a balance of nickel and impurities. Titanium or another MC carbide former can be added to enhance thermal stability of the alloy.

The invention discloses a nickel based brazing filler metal in form of an alloy containing or consisting of between 20 wt % and 35 wt % chromium, between 7 wt % and 15 wt % iron and between 2.5 wt % and 9 wt % silicon, between 0 wt % and 15 wt % molybdenum, unavoidable impurities and the balance being nickel. The solidus temperature of the brazing filler shall be between 1140 C. and 1240 C. The brazing filler metal is suitable for production of catalytic converters and heat exchangers.

The invention also discloses a brazing method.

A compositionally graded alloy construction for separating a low oxygen content corrosive environment from a high oxygen content oxidizing environment includes a wall having a wall thickness and a first surface segment for contacting the low oxygen content corrosive environment, and a second surface segment for contacting the high oxygen content oxidizing environment. The alloy comprises, in weight percent: 0 to 5 Al; 5 to 30 Cr; 0 to 20 Co; 0 to 70 Fe; 0 to 2 Nb; 0 to 2 Ta; 0 to 3 Ti; 0 to 1 Si; 0 to 1 V; 0 to 2 Mn; 0 to 5 Cu; 0 to 30 Mo; 0 to 30 W; 0 to 0.1 P; 0 to 1 Zr; 0 to 1 Hf; 0 to 0.1 Y; 0.05 to 0.5 C; 0 to 0.1 N; and balance Ni.

In a method for producing, and/or installing into a system, a component with one or more weld seams containing a nickel-chromium-aluminum alloy, with (in wt. %) >18 to 33% chromium, 1.8-4.0% aluminum, 0.01-7.0% iron, 0.001-0.50% silicon, 0.001-2.0% manganese, 0.00-0.60% titanium, respectively 0.0-0.05% magnesium and/or calcium, 0.005-0.12% carbon, 0.0005-0.050% nitrogen, 0.0001-0.020% oxygen, 0.001-0.030% phosphorus, max. 0.010% sulfur, max. 2.0% molybdenum, max. 2.0% tungsten, remainder 50% nickel and impurities, the component containing semi-finished products of wrought alloy, after welding, only the weld seams and surrounding heat-affected zones undergo annealing between greater than 980 and 1250 C. for 0.05 minutes-24 hours, then cooling in inert protective atmosphere, moving protective gas or air, where: Cr+Al28 and Fp39.9 with Fp=Cr+0.272*Fe+2.36*Al+2.22*Si+2.48*Ti+0.374*Mo+0.538*W11.8*C, Cr, Fe, Al, Si, Ti, Mo, W and C being element wt. % concentrations.