Fig. 1. Experimental diagram of LIBS

Fig. 2. LIBS of sinter

Fig. 3. Effects of pressures on spectral signals of Fe, Si,and Ca. (a) Signal stability; (b) signal intensity

Fig. 4. Effects of laser energy on spectral signals. (a) Fe Ⅱ 248.266 nm; (b) Si Ⅰ 288.158 nm; (c) Ca Ⅰ 647.166 nm

Fig. 5. Effects of delay time on spectral signals of laser-induced sinter samples. (a) Fe Ⅱ 248.266 nm; (b) Si Ⅰ 288.158 nm;(c) Ca Ⅰ 647.166 nm

Fig. 6. Test results of spectral signal stability of different elements. (a) Fe element; (b) Si element; (c) Ca element

Fig. 7. Calibration curves before processing by internal standard method. (a) Intensity ratio of Ca Ⅰ 647.166 nm and Si Ⅰ 288.158 nm; (b) intensity ratio of Ca Ⅰ 422.673 nm and Si Ⅰ 288.158 nm

Fig. 8. Calibration curves after processing by internal standard method. (a) r₁/r₂; (b) r₃/r₂