摘要:
A reduced thermal conductivity thermal barrier coating having improved impact and erosion resistance for an underlying metal substrate of articles that operate at, or are exposed to, high temperatures. This coating comprises an inner layer nearest to the underlying metal substrate comprising a ceramic thermal barrier coating material, as well as a protective outer layer adjacent to and overlaying the inner layer and having an exposed surface. The outer layer has a thickness up to about 5 mils (127 microns) sufficient to impart impact and erosion resistance to the thermal barrier coating, and comprises a zirconia-containing ceramic composition having a c/a ratio of the zirconia lattice in the range of from about 1.011 to about 1.016 and stabilized in the tetragonal phase by a stabilizing amount of a stabilizing metal oxide selected from the group consisting of yttria, calcia, ceria, scandia, magnesia, india, ytterbia and mixtures thereof. This coating can be used to provide a thermally protected article having a metal substrate and optionally a bond coated layer adjacent to and overlaying the metal substrate. The thermal barrier coating can be prepared by forming the inner layer comprising the ceramic thermal barrier coating material, followed by forming on the inner layer the protective outer layer.
摘要:
An article protected by a thermal barrier coating system is fabricated by providing an article substrate having a substrate surface, thereafter depositing a bond coat on the substrate surface, the bond coat having a bond coat surface, and thereafter processing the bond coat to flatten the bond coat surface. A thermal barrier coating is deposited overlying the bond coat surface. The thermal barrier coating is yttria-stabilized zirconia having a yttria content of from about 3 percent by weight to about 5 percent by weight of the yttria-stabilized zirconia.
摘要:
An electron beam physical vapor deposition (EBPVD) apparatus and a method for using the apparatus to produce a coating material (e.g., a ceramic thermal barrier coating) on an article. The EBPVD apparatus generally includes a coating chamber that is operable at elevated temperatures and subatmospheric pressures. An electron beam gun projects an electron beam into the coating chamber and onto a coating material within the chamber, causing the coating material to melt and evaporate. An article is supported within the coating chamber so that vapors of the coating material deposit on the article. The operation of the EBPVD apparatus is enhanced by the inclusion of a crucible that supports the coating material and is configured to be efficiently cooled so as to reduce the rate at which the process temperature increases within the coating chamber.
摘要:
A bushing includes a bronze backing layer having a first axial end, a second axial end, and a central opening, the bushing having a cylindrical shape and a porous bronze layer. PTFE or other suitable low friction material is impregnated into the porous bronze layer at one of a radially inner or outer surface of the bushing. A PTFE or other suitable low friction material topical layer is disposed adjacent the impregnated layer. The bushing may optionally comprise a flange which also includes the bronze backing layer, the porous bronze and impregnated layer, and the topical layer on an axially inner or outer surface.
摘要:
A thermal barrier coating and deposition process for a component intended for use in a hostile thermal environment, such as the turbine, combustor and augmentor components of a gas turbine engine. The TBC has a first coating portion on at least a first surface portion of the component. The first coating portion is formed of a ceramic material to have at least an inner region, at least an outer region overlying the inner region, and a columnar microstructure whereby the inner and outer regions comprise columns of the ceramic material. The columns of the inner region are more closely spaced than the columns of the outer region so that the inner region of the first coating portion is denser than the outer region of the first coating portion, wherein the higher density of the inner region promotes the impact resistance of the first coating portion.
摘要:
A turbine airfoil having an improved impact and erosion resistance. The airfoil comprises: (a) a base segment having an impact resistant leading edge section proximate to the leading edge comprising a material having having a yield strength of least about 250 ksi and an elongation percentage of about 12% or less; and (b) an erosion resistant coating overlaying the base segment at least in the leading and trailing edge portions of the pressure side, the erosion resistant coating comprising at least one ceramic layer having at least one of the following properties: (1) an erosion value of at least about 200 g. of erodent to cause a thickness loss of about 15-20 microns; (2) an erosion volume loss value (V) of about 1.9 or less as defined by the equation V=H−0.18×E0.75×F−1.65 where H is hardness, E is elastic modulus and F is fracture toughness; and (3) an F value of at least about 1.5 MPa*m1/2. The erosion resistant coating can comprise alternating ceramic and metallic layers and is typically formed by a method involving the step of forming on the pressure side of the base segment of the airfoil in alternating fashion at least one ceramic layer and at least one metallic layer.
摘要:
A rod end bearing comprising a body comprising a ring portion and a rod portion. The ring portion comprises a ring having an opening, the opening having a center axis. The rod portion comprises a first rod extending radially from the ring in a direction perpendicular to the center axis. The opening having a geometry sufficient to support a substantially spherical ball bearing, and permit rotation of the ball bearing inside the ring. The inner periphery of the ring is in contact with the ball bearing and includes a wear coating. An antifriction coating is disposed on a surface selected from the group consisting of a surface of the wear coating, a surface of the ball bearing and combinations thereof. The antifriction coating maintains a coefficient of friction between the wear coating and the ball bearing of up to about 0.95 in atmospheres substantially devoid of water vapor.
摘要:
A method for surface treating a titanium gas turbine engine component. The method includes providing a gas turbine engine component having a titanium-containing surface. The component is heated to a temperature sufficient to diffuse carbon into the titanium and below 1000° F. The surface is contacted with a carbon-containing gas to diffuse carbon into the surface to form carbides. Thereafter, the carbide-containing surface is coated with a lubricant comprising a binder and a friction modifier. The binder preferably including titanium oxide and the friction modifier preferably including tungsten disulfide. The coefficient of friction between the surface and another titanium-containing surface is less than about 0.6 in high altitude atmospheres.
摘要:
A variable stator vane assembly and a bushing thereof. The bushing includes a metal bushing body and a wear-resistant coating. The assembly includes a rotatable trunnion and a first metal bushing. The trunnion is capable of being located in a through hole extending between outer and inner surfaces of a compressor casing of a gas turbine engine. The first metal bushing is capable of being located in the through hole proximate the outer surface to surround a first portion of the trunnion when the trunnion is located in the through hole. The first metal bushing and the first portion have wear-resistant coatings which are in mutual contact, apart from any intervening lubricant, when the trunnion and the first metal bushing are located in the through hole and the trunnion is rotating with respect to the first metal bushing.
摘要:
Method for preparing reduced thermal conductivity thermal barrier coating having improved impact resistance for an underlying substrate for high temperature applications. An exemplary method includes depositing a first zirconia-containing ceramic composition having a c/a ratio of about 1.011 to about 1.016 and stabilized in the tetragonal phase by yttria, calcia, ceria, scandia, magnesia, india, lanthana, gadolinia, neodymia, samaria, dysprosia, erbia, ytterbia, europia, praseodymia, and mixtures thereof, and including about 0.3 to about 0.5% by weight lanthana, neodymia, gadolinia, and mixtures thereof The first material forms a high fracture toughness inner layer having a fraction of porosity of about 0.20 or less, and a thickness in the range of from about 0.5 to about 2 mils. The method includes depositing a ceramic material forming an outer thermal insulating layer overlying the inner layer and having a greater fraction of porosity than the inner layer.