Patent claim: A method for producing a seal comprising forming a seal from substrate material the seal comprising a first portion having a first abradability and a second portion having a second abradability the first abradability being different from the second abradability.

Related passage: The most important elements of the proposed approach are summarised in table 2 as given belowTable 2 Overview over essential elements of the proposed system.Characteristic Detailed characteristicShape design of the abradable coating systemAbradable coating system characterised in thatit is preformedit is presintered characterized in that it can bethe tissue onlythe matrix and the tissueor it is a green body characterized in that it can bethe tissue onlythe matrix and the tissuethe tissue and additional organic polymer in order to reinforce the tissue for an easier applicationit is monoblock or with several blocksit is designed with texturing in the cm range e.g.the sides are harder than the middle zoneits surface is optionally textured in the cm range so that it is achieved e.g.by isostatic hot pressing or by using polymers with a grid structure or any texturing with preferably a honeycomb structureits core has a texture in the millimeter and micrometer range texturedThis type of structuring is characterised in thatfibers are oriented in the direction y preferably or x depending ofthe operating conditionsthe matrix can be locally reinforced by abrasive particlesfibresthe matrix is infiltrated in a graded manner along zits erosion resistance and abradability are graded and is characterised in thatthe materials are abradable in the plan xy in the middle zone where the blading is running in and it is erosion resistant in the plane xy on the side in order to stabilize the inner coatingin the middle zone the coating abradability is graded along the direction z in order to give the best adhesion and the best stability of the layer integrity of the system and abradabilityit can enable cooling of the partsIt is thermally insulating light weightits lifetime min 1C cycleComposition of the abradablecoating systemA tissue and a matrixThe tissue is characterised in thatit is made of ceramic or glass or ceramicmetal composite or combinations thereofit is woven e.g.textile or cloth or non woven e.g.feltAn alternative to the tissue can be to use a foam.Matrix is characterised in that it contains a complex composition of filler particlesfibres and binders.The filler particlesfibres can be oxide or oxide precursors or non oxide.They can be selected among other criteria on the criteria of their hardnessabrasive potential.The binder can be an organic or inorganic polymer.It is applied as a liquid which is hardenedThe several different tissues can optionally be combined within one block or be used for different assemblies.One or several different matrixes can be used within one assembly.Preparation of the abradable coating systemsee embodiments according to Figs 710 and the corresponding description or combination thereof optionally intermediate drying andor curing is possibleApplication of the abradable coating systemOnsite mounted or dismountedOn metallic substrate e.g.stator heat shield which can have a curvature and which have optionally a surface treatment e.g.rough surface obtained by blasting rough surface of metallic coatingthe abradable coating is e.g.glued to the metallic substrate and the glue is cured by for example light radiations for e.g.UV IR...or heat for e.g.resistor or heat of the engine...Thickness of the abradable coating system Up to 4 mmIt can be adjusted to the need by a using for example several tissuestissue layersRepair process Examplesonly replacement of the central part or full replacementonly replacement of the surfacial coating and not up to the base metalon mounted or dismounted partControl of the coating quality e.g.thermography