A watertube panel portion for a fluidized bed reactor and a corresponding method. The watertube panel portion includes multiple parallel metal tubes having a tube length L1, an outer surface, an original outer diameter OD1, and an original wall thickness WT1, and a circumferentially extending recess formed in a central portion of each of the tubes, between first and second end portions. The recess has a constant depth D that is less than the wall thickness WT1. The recess encircles the outer surface of the central portion of the metal tube. A circumferentially extending metal coating has a constant thickness of at most the depth D of the recess to blanket the recess of each of the multiple metal tubes. A fin is continuously welded between each pair of adjacent tubes.

A method of both coating a substrate with aluminum oxide and infusing the substrate with elemental aluminum is disclosed. In one example, the method includes providing a metal powder/polymer binder slurry, the slurry having a solvent, an organic binder, metal granules and a seed element, wherein the metal granules include Al; dispersing the slurry upon a Cr-containing surface; after dispersing the slurry, exposing the slurry to air and maintaining the temperature of the slurry and substrate below 110 C. to remove at least a portion of the solvent from the slurry; and, in a combined step, both exposing the binder, metal granules and substrate to air and heating the remaining slurry and substrate at a temperature less than or equal to 1000 C. to both diffuse at least a portion of the metal of the metal granules into the substrate and coat the substrate with aluminum oxide.

A feedstock for a thermal spray process is disclosed. The feedstock includes fly ash derived from coal combustion. A method for coating an article is disclosed. The method includes applying the feedstock as a coating precursor by a thermal spray process. The fly ash preferentially forms a coating disposed on a substrate of the article.

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.

The boiler (1) according to an aspect of the present invention is provided with a boiler main body (3) and a steel support frame (5) that suspends and supports the boiler main body (3). The boiler main body (3) is provided with: a furnace wall (11) composed of water pipes (15) and plate-like fins (16) arranged in an alternating manner; an internal element (4) housed inside the furnace wall (11); and a buffering mechanism (20) configured to attenuate vibration energy when relative displacement, of the internal element (4) with respect to the furnace wall (11), occurs that exceeds a predetermined value. The buffering mechanism (20) is disposed between the furnace wall (11) and the internal element (4) in the main vibration direction of the internal element (4), and the load on the buffering mechanism (20) caused by interference is transmitted to the fins (16).