Forming a porous multilayer material includes forming a multilayer material on a substrate. Forming the multilayer material includes alternately forming a sacrificial layer and a semi-sacrificial layer, where the sacrificial layer includes a first metal and the semi-sacrificial layer includes the first metal and a second metal or metallic alloy. Forming the porous multilayer material further includes removing at least a portion of the first metal from each of the sacrificial and semi-sacrificial layers to yield the porous multilayer material. The porous multilayer material includes a multiplicity of metal-containing layers, each layer having a thickness in a range between about 5 nm and about 100 nm and bonded to an adjacent layer. Each layer includes chromium, niobium, tantalum, vanadium, molybdenum, tungsten, or a combination thereof. A void is defined between each pair of layers, and a density of porous the multilayer material is <1% bulk density.

A method of forming a multilayered zinc alloy coating comprises steps of providing a bath of an aqueous electrolyte including zinc and a second electrodepositable component in an electrolytic cell having an anode and a cathode; applying a current or voltage between the anode and the cathode; modulating the applied current or voltage over time between at least two current or voltage values to thereby modulate the current density over multiple cycles between at least two current density values, wherein a first current density value is in a range of 0.3 to less than 2 A/dm.sup.2 and a second current density value is higher than the first current density value and is in a range of 0.6 to less than 5 A/dm.sup.2; and controlling the modulation of the applied current or voltage to obtain a multilayered structure having multiple layers of one or more of alternating proportions of the second component, alternating corrosion potential, alternating grain size, and alternating grain orientation, wherein one or more of the multiple layers has a thickness in the range of 1 to 10 μm.

A coated cutting tool including a substrate and a coating layer formed on the substrate, wherein the coating layer has an alternately laminated structure of a first layer and a second layer, the first layer contains a compound having a composition represented by (Al.sub.aTi.sub.1-a)N (0.80 ≤ a ≤ 0.95), the second layer contains a compound having a composition represented by (Al.sub.bM.sub.cTi.sub.1-b-c)N (M represents at least one of Si or B, 0.80 ≤ b ≤ 0.95, and 0 < c ≤ 0.20), a and b satisfy |a-b| ≤ 0.05, and an average thickness of the alternately laminated structure is 1.0 .Math.m or more and 10.0 .Math.m or less.

The present invention relates to a method for producing a blade or blade arrangement of a turbomachine, which features the following steps: producing a blade (4) from at least one blade material, machining the blade in at least one region of the blade by a surface machining process, cleaning the surface of the blade depositing an erosion protection coating (10) of at least two layers of different hardness by physical vapor deposition in the at least one region, machining the erosion protection coating (10) by a coating smoothing process in order to establish a defined surface roughness.

Furthermore, the invention relates to correspondingly produced blades or blade arrangements.

The present disclosure provides a multilayer coated cutting material having increased wear resistance at high temperatures, a method for manufacturing the same, and a cutting tool insert for mechanical machining including the same. According to an embodiment of the present disclosure, the multilayer coated cutting material includes a cemented carbide, cermet, ceramic, a cubic crystal boron nitride-based material or a hard alloy body of high-speed steel, and a cutting layer positioned on the base material and configured in multiple layers.

In a surface-coated cutting tool in which a hard coating layer having a total layer thickness of 0.5 to 10 μm is deposited on a surface of a tool body made of WC-based cemented carbide or TiCN-based cermet, the hard coating layer has an alternately laminated structure of A layers and B layers, in a case where the A layer is: (Al.sub.aTi.sub.1-a)N (here, a is in atomic ratio), the A layer satisfies 0.50≦a<0.75, in a case where the B layer is: (Al.sub.bTi.sub.1-b)N (here, b is in atomic ratio), the B layer satisfies 0.75≦b≦0.95, and when a layer thickness per layer of the A layers is represented by x (nm) and a layer thickness per layer of the B layers is represented by y (nm), 5y≧x≧3y and 250 (nm)≧x+y≧100 (nm) are satisfied.

A component of a gas turbine engine comprises a substrate, a corrosion resistant top layer, and an intermediate corrodible layer disposed between the corrosion resistant top layer and the substrate. When corroding, the intermediate layer has a color contrasting with a color of the top layer. A method of detecting a crack when it penetrated the top layer in a component of a gas turbine engine having a corrosion resistant top layer and an intermediate corrodible layer comprises, in sequence, observing that at least one area of the component has a color contrasting with that of the top layer; determining that the color of the at least one area is a result of corrosion of the intermediate corrodible layer; and determining that the top layer has a crack as a result of determining corrosion of the intermediate layer. A method of facilitating crack detection in a component is also presented.

The present disclosure provides a multilayer coated cutting material having increased wear resistance at high temperatures, a method for manufacturing the same, and a cutting tool insert for mechanical machining including the same. According to an embodiment of the present disclosure, the multilayer coated cutting material includes a cemented carbide, cermet, ceramic, a cubic crystal boron nitride-based material or a hard alloy body of high-speed steel, and a cutting layer positioned on the base material and configured in multiple layers.

Provided is a coated cutting tool, which includes a hard coating film containing a layer (b) formed of a nitride or a carbonitride, a layer (c) which is a layered coating film formed by alternately layering a nitride or carbonitride layer (c1) that contains 55 atom % or more and 75 atom % or less of Al, Cr having a second highest content percentage, and at least Si and a nitride or carbonitride layer (c2) that contains 55 atom % or more and 75 atom % or less of Al and Ti having a second highest content percentage, each layer having a film thickness of 50 nm or less, and a layer (d) that is a nitride or carbonitride that contains, with respect to a total amount of metal elements (including metalloid elements), 55 atom % or more and 75 atom % or less of Al, Cr having a second highest content percentage.

The present invention addresses the problem of providing a piston ring covered with a DLC coating that has excellent wear resistance and shows a low attacking property on a cylinder bore sliding surface. The problem is solved by a piston ring which is used in the presence of an engine lubricating oil and includes a DLC coating on an outer peripheral sliding surface. The DLC coating has an sp.sup.2 component ratio of 0.5 to 0.85 as determined from a TEM-EELS spectrum obtained by a combination of a transmission electron microscope (TEM) and electron energy loss spectroscopy (EELS), as well as a coating hardness of 12 GPa to 26 GPa and a Young's modulus of 250 GPa or less as measured by a nanoindentation method.