Nitriding annealing hot working Tool steel H13 (DIC, 200X), comet trailing defect

    Occasionally, during the preparation process of metallographic samples, it may be encountered; Comet Trailing; Once encountering this defect phenomenon, there is no need to rush. You can try the following solutions, and using a hard, lint-free metallographic polishing cloth is one of the essential solutions. We need to take targeted measures based on the specific causes of such defects, in order to achieve effective solutions.


The generation of comet tail defects is mostly due to poor adhesion of hard phases in soft substrates, resulting in unidirectional fine grooves originating from particles or pores. There are generally several reasons for this.

Bright field of view, 200X comet tail defect

    Firstly, as shown in the above figure; Comet Trailing; Defects, visible in a 200X image under bright field, with a large amount of&quo; visible; Comet Trailing; The presence of defects is mainly caused by abrasive particles embedded between the resin and the sample gap. The solution is very simple. It is necessary to perform ultrasonic cleaning before polishing, and then use a hard, lint free metallographic polishing cloth combined with a polishing agent for polishing. During the polishing process, it is important to reduce the loading pressure appropriately and not pursue a fast removal rate to avoid; Comet Trailing; Obtain an ideal polished surface while defects are present.

Quenched and hardened steel (DIC, 500X), comet trailing defect

    Secondly, as shown in the above figure, the comet trailing defect is mainly caused by the trailing of carbides in quenched and hardened steel, which may have been caused by single-phase polishing. The solution is to avoid single-phase polishing while still using a hard, lint-free metallographic polishing cloth combined with a polishing agent for polishing, and appropriately reducing the loading pressure to obtain a defect free polished surface.

    However, for porous materials, it is also relatively easy to generate this kind of&quo; Comet Trailing; For defects, in addition to ultrasonic cleaning before polishing, resin or wax can also be used to seal the pores before polishing. However, no matter which measure is taken, it cannot be separated from the two key points of using a hard lint free polishing cloth combined with a polishing agent for polishing, and appropriately reducing the loading pressure. Sample preparation encountered&# quo; Comet Trailing; Defect, you can try this type of metallographic polishing cloth, which refers to a hard and lint free metallographic polishing cloth. Try it! Let's see if we can help you solve this problem.