## 4 Discussion on Array Micro Grooves Processing  
Nanosecond pulse lasers are a type of short pulse laser. In the process of material removal, the laser energy in the processing area can cause the matrix material to decompose and sublimate. As shown in Figure 11a, in conventional laser processing, some of the SiC material is sublimated into a gaseous form of SiC(g) with the action of the laser, and some of the SiC material was decomposed into Si(g) and C(g) [24]. The SiC (g) and Si(g) reacted with O\({}_{2}\) to generate SiO\({}_{2}\)(g), which solidified at room temperature. The C(g) reacted with oxygen in the air to generate CO\({}_{2}\) and CO gas during the processing. In the conventional nanosecond laser processing, the ablation reactions were as follows:  
\[\text{SiC(s)}=\text{SiC(g)} \tag{1}\]  
\[\text{SiC(s)}=\text{Si(g)}+\text{C(g)} \tag{2}\]  
\[2\text{SiC(s)}+3\text{O}_{2}(\text{g)}=2\text{SiO}_{2}(\text{g)}+2\text{CO}_{ 2}(\text{g)} \tag{3}\]  
\[\text{Si(s)}+\text{O}_{2}(\text{g)}=\text{SiO}_{2}(\text{s)} \tag{4}\]  
\[\text{C(g)}+\text{O}_{2}(\text{g)}=\text{CO}_{2}(\text{g)} \tag{5}\]  
\[2\text{C(g)}+\text{O}_{2}(\text{g)}=2\text{CO}(\text{g)} \tag{6}\]  
In the bottom of the grooves in the processing area, the laser energy was enough to vaporize the material, and the gaseous products diffused to the outside of the groove and solidified. As shown in Figure 3, oxidation products firstly accumulated around the groove. With the increase of processing times, the oxidation products sp  
Figure 11: Schematic of material removal in the fiber nanosecond laser processing of SiC material: (**a**) conventional laser processing, (**b**) blowing-assisted laser processing.  
Figure 10: SEM of workpieces of different widths processed by blowing-assisted laser processing, shown after ultrasonic cleaning: (**a**) width of 1 mm, (**b**) width of 0.8 mm, (**c**) width of 0.6 mm.  
groove. Unfortunately, the accumulated products could shield part of the laser energy, and this material was melted and recast. As a result, the poor processing quality was obtained.  
In blowing-assisted laser processing, silicon carbide material was processed normally by the laser, and oxidation products were also formed. As shown in Figure 11b, with the assistance of blowing, the oxidation products could be blown away from processing area. There were only a small amount of products near the groove, which would not affect the processing. With the increase of processing depth and the decrease of processing width of the groove structures, the blowing also effectively removed the products, thus avoiding the accumulation of products in the processing area. Therefore, deeper and narrower groove structures of good processing quality could be obtained by blowing-assisted laser processing. In addition, compared with conventional laser processing, waste products could be removed from the processing area more quickly before they had a chance to react, enabling the blowing-assisted laser processing to obtain higher processing efficiency. To further verify that blowing can improve the laser processing capability of silicon carbide, array microgroove microstructures of 1 mm \(\times\) 1 mm were processed 100 times, 150 times, and 200 times by blowing-assisted laser processing. As shown in Figure 12, the contour of array grooves were clear and the bottom of the groove structures were bright without molten deposits. From the cross-sectional profile, it can be found that the depth of the groove structures gradually increased with the increase of processing times. The processing depth of 1 mm \(\times\) 1 mm array grooves can be 0.658 mm when processed by the blowing-assisted laser processing 200 times. It can be concluded that blowing-assisted laser processing is more suitable for the processing of microstructures on silicon carbide materials, compared with the conventional laser processing.