1.6.3 Control of Grain Growth
The most effective approach for inhibiting grain growth involves the use of additives (dopants) that are incorporated into the powder to form a solid solution. The concentration of the dopant (the solute) is often believed to be well below its solid solubility limit in the ceramic (the host) but this is not clear in some systems.
1.6.4 Grain Growth and Pore Evolution in Porous Compacts
In porous powder compacts, grain growth is very limited in the initial stage of sintering but coarsening of the microstructure can occur by surface diffusion and vapor transport. The mechanism most commonly cited for coarsening in this early stage of sintering. It assumes that the coarsening processes (surface diffusion; vapor transport) lead to rounding of the particle shapes and growth of the necks between the particles, thereby producing the structural changes for boundary migration to be energetically favorable.
1.6.5 Interactions between Pores and Grain Boundaries
The attainment of high density during sintering depends on the ability to stabilize the microstructure such that the pores and the grain boundaries remain attached. For an idealized geometry of an isolated, spherical pore at a grain boundary, typical of an idealized microstructure in the final stage of sintering, the interaction between the pore and the boundary used to determine the conditions for pore attachment and breakaway.
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
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