**Author details**

trapped porosity were also observed on the samples' surface. A complex array of mechanisms involving solid, liquid, and vapor phases led to formation of these morphologies including

394 Applications of Laser Ablation - Thin Film Deposition, Nanomaterial Synthesis and Surface Modification

In addition to the laser ablation of ultra-high-temperature ceramics, the laser beams were also used to characterize the ablation resistance of ultra-high-temperature ceramic coatings. Liu et al. [30] prepared a two-layer SiC-ZrC coating on C/C composite by chemical vapor deposition method. They characterized the ablation resistance of the coating using a continuous CO2 laser beam and investigated the laser ablation behaviors and ablation mechanisms of the SiC-ZrCcoated C/C composites. The results indicated that the ablation depth and width increased with increasing the laser power. Laser ablation resistance of the composites was greatly improved by the SiC-ZrC coating. They found three ablation regions on the ablated coating surface and discussed the formation mechanism. At the ablation center, the ablation was thought to be dominated by the blast and sublimation processes. At the transitional zone, the main ablation mechanism was evaporation. At the ablation edge, the ablation was mainly controlled by the oxidation process. Li et al. [31] also employed the laser beam to characterize ablation resistance of ultra-high-temperature ceramic coatings. A TaC coating was prepared on C/C composite by chemical vapor deposition to improve ablation resistance of the composite at high temperatures. They tested the ablation resistance of TaC coating and investigated ablation mechanism.

Laser ablation is a facile, reliable, and economical method to evaluate ablation resistance of materials. The fundamentals of laser-material interactions were discussed from the physical aspects and chemical aspects. The physical aspects mainly involved the absorption of laser radiation, heating and propagation, melting, vaporization, and solidification. The chemical aspects mainly involved the decomposition of materials and the reaction between the materials

melting, oxidation, volatilization, and liquid flow.

**5. Conclusions**

**Figure 11.** Macro-morphologies of laser-heated (a) ZrB2/20 vol.% SiC and (b) ZrB2 samples.

Yonggang Tong1,2\*, Xiubing Liang1 , Shuxin Bai2 and Qing H. Qin3

\*Address all correspondence to: tygiaarh419@163.com

1 National Engineering Research Center for Mechanical Product Remanufacturing, Academy of Armored Forces Engineering, Beijing, China

2 College of Aerospace Science and Engineering, National University of Defense Technology, Changsha, China

3 Research School of Engineering, Australian National University, Canberra, Australia
