engleski

Wear mechanisms of monolithic ceramics

Advanced ceramics have been extensively used as anti-wear materials for various engineering applications, because of the wide range of their good properties, such as high temperature stability, hardness and strength, good wear and corrosion resistance, particularly at elevated temperatures where metal matrix composites have proven to be inadequate. Among the advanced oxide engineering ceramics, alumina ceramics have the unique combination of desirable properties for different applications: good wear and corrosion resistance, high hardness, excellent oxidation resistance and low production costs. Wear is one of the most commonly encountered industrial problems, leading to frequent replacement of components. Solid particle erosion can be defined as the degradation of material that results from repeated impacts of small solid particles. It occurs in a gaseous or a liquid medium containing solid particles. The present medium can change the velocity and direction of erodents (solid particles). If the erosion occurs at impact angles between 0° and 30°, it is regarded as abrasive erosion, while the one occurring between 60° and 90° is called impact erosion. Depending on the material and operating parameters, erosive wear can occur with plastic deformation and/or brittle fracture. Ductile materials will undergo wear by a plastic deformation process, where the material is removed by the displacing or cutting action of the eroding particle. On the other hand, eroded brittle material will be removed by the formation and intersection of cracks that cause grain ejection. In this investigation, solid particle erosion tests were conducted to investigate the erosion wear behavior of the slip cast monolithic high purity alumina (Al2O3) advanced ceramics at different particle impact angles at the room temperature. The erodent impact angles were 30°, 60° and 90°. Dry silicon carbide (SiC) was used as an erodent. Erosion mechanisms of all prepared ceramic samples were evaluated by measuring the weight loss and roughness parameters (Ra, Rz, Rm).

alumina ceramics ; wear

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