What Is Sintering

1.1 What Is Sintering?
Sintering is a processing technique used to produce density-controlled materials and components from metal or/and ceramic powders by applying thermal energy. Hence, sintering is categorized in the synthesis/processing element among the four basic elements of materials science and engineering, as shown in Figure 1.1. As material synthesis and processing have become crucial in recent years for materials development, the importance of sintering is increasing as a material processing technology. Sintering aims, in general, to produce sintered parts with reproducible and, if possible, designed microstructure through control of sintering variables.
The most important and beneficial uses of sintering is the fabrication of sintered parts of all kinds, including powder-metallurgical parts and bulk ceramic components. Figure 1.2 shows the general fabrication pattern of sintered parts. Unlike other processing technologies, various processing steps and variables need to be considered for the production of such parts. For example, in the shaping step, one may use simple die compaction, isotactic pressing, slip casting, injection molding, etc., according to the shape and properties required for the end product. Depending on the shaping techniques used, not only the sintering conditions but also the sintered properties may vary considerably.