Technology of Microstructural Analysis BRAMANTYO UTOMO1306387840INTRODUCTION :Kind of superalloy/TBC system consist of plasma lasma-sprayed zirconium-yttrium ceramic layer with a nickel-chromium- aluminium-yttrium bond coat on a substrate made of nickel-based superalloy.. And the application in aerospace and gas turbine engine. Sometimes in automotive use a piston head for diesel engine is coated to enhance lifetime and performance as far as fuel demand reduction and power improvement are concerned. which is the result of the applied material and thermal contrast between the coating and the base metal.METHODOLOGY : A scope of investigations comprised realization of a process of preparation of metallographic micro-sections, beginning from a cutting moment, through mounting, grinding and polishing. A standard method of preparation of micro-sections, typical for conventional layers was used and microstructural observation, from a point of view of presence of artefacts of mechanical origin was carried out. Metallographic investigations of coatings, thermally sprayed, including coating barrier layers type TBC (thermal barrier coating), are basic sources of several pieces of information, which enables to assess qualitatively the ceramic layers and interlayers. However metallographic procedures are very difficult to be controlled and in an effect of faulty preparation of samples, the got results can be essentially different from a real state for the first step.Cutting : The fuction of cutting is for ealized in order to prepare samples to further investigations . In TBC we use some several cutting methods and the result will shown after finished. manual abrasive saw, automatic abrasive-cutting machines , low-rotary diamond precise saws or bigger high-rotary precise cut-off machines to get the best result of cutting, smooth and flat form. It depends by individual parameters of cutting process. We must considered place of defects and to locate the sample. In abrasive methods disks comprise aluminium oxide or silicon carbide with additives of phenol resins. Cutting of hard materials requires using disks, relatively soft. Use of methods of precise cutting is especially an effective method to get a good quality of surface. The rotation and speed cutting force must considered in case of cutting because will effect for cutting quality. These samples should be fixed and positioned in such a way that defects of coating are minimized.Mounting : Mounting is a method of placing a sample in a media in order to ease handling the small size and irregular shape of the sample without damage it. The small-sized specimen or specimen that does not have regularity form will be hard to be handled, especially when they are on the stage of grinding and polishing. Two types of mounting in cold and hot mounting. If we use some requirements of hot mounting this application f higher temperature and pressure isnt best solution for ceramic. It will porous layers when the penetration through resins in ceramic layers is too small. And resins effecting relating to epoxy resins of less viscosity, which are used in mounting in cold. In effect, grinded samples with a ceramic layer of less penetration degree through resin undergo easily cracking. Additionally, during mounting process, pressure and temperature generate cracks, what causes ceramic layers type TBC not to be suitable for mounting by this method. Mounting in cold sample protection of a sample in mixture epoxy and acrylic and in polyesters. Because cold this application of course realized in temperature and sprayed relatively wide. And mounting cold be carried out in vacuum because vacuum will remove of air. The type of resins of short time of congealing and low viscosity. Use transparent resins or epoxy produce enables precisely to detect artefacts and distinguish Grinding : Grinding aims to smoothening the sample surface by rubbing a grinding paper over the surface. The sample which has been cut or corrosive sample has coarse surface. This coarse surface must be flattening in order to ease the structure observation Use brasive papers on base of SiC, Al2O3 and ZrO2 are used. Carbide papers are used in a wide range of gradation from 60 to 1200, and oxide papers are used for rough grinding in gradation 60 to 120. In order to get satisfying quality of surface, grinding with papers of more and more gradation is used. But SiC makes some problems it makes differences in quality of surface of treated samples with layers. In abrasion process the product of grinding will different with each other because we must consider with direction and the number of grid. And the final of grinding is the abrasive materials of very fine granularity. This stage is not able to remove defects and deformations, which originated in sooner stages. However, there is no consensus, when grinding finishes and polishing begins. As far as rough grinding and final grinding is a multi-stage process. Grinding disks are made of rigid metal disks with a composite strap on surface, which is not an abrasive material. Diamond particles, during a grinding process, deposit themselves on composite substrate, and thanks to it a process of final grinding is realized Polishing : Polishing is done to obtain a smooth sample surface that free from any scratch and shine like mirror, also to disappear the irregularity of the sample until 0.01 m in order. The sample surface that will be observed from the microscope must be very flat. If the sample surface is rough, the microstructure observation will be hard to do because the light that comes from the microscope will be reflected by the sample surface. In polishing abrasive agent enables to avoid sensible defects of thermal barrier. Washing time should be minimal in order to avoid defects A polishing process has to remove any remaining defects on treated surface and other defects after sooner actions. aterial (SiO2, Al2O3) in co- operation with polishing clothes. In modern polishing methods, more than one step is applied. A view of the TBC layers of a new type, after having finished the whole procedureSUMMARY :We can conclude of the result microstructural investigation on samples by several step cutting, mounting,grinding, polishing. The preparation has a meaning influence on correct structural elements, which are subjects of criterion assessment in quality assessment of the TBC layers.The investigation showed that a new kind of a used material was also characterized by strong on applied procedures and conventional layers type YSZ as well. And cold mounting is recommended as for conventional materials