On-line temperature monitoring of plasma sprayed coating is presented, which is based on IR pyrometery combined to robot trajectories. Temperature fields of the substrate before spraying and the deposited coating when...On-line temperature monitoring of plasma sprayed coating is presented, which is based on IR pyrometery combined to robot trajectories. Temperature fields of the substrate before spraying and the deposited coating when the damage happens are taken to investigate the temperature fluctuation information. Experimental results demonstrate that coating damage always occurs in the temperature transition area of the substrate from the higher to the lower, as well as the higher temperature area. The temperature difference between the peak and the mean of the relevant regions is beyond 30 - 50℃ or even higher. This case provides the omen of coating damage and the focusing scopes for the process control of coating temperature in plasma spraying展开更多
Single-pulse and multi-pulse damage behaviors of ＂standard＂ （with A/4 stack structure） and ＂modified＂ （with reduced standing-wave field） HfO2/SiO2 mirror coatings are investigated using a commercial 50-fs, 800...Single-pulse and multi-pulse damage behaviors of ＂standard＂ （with A/4 stack structure） and ＂modified＂ （with reduced standing-wave field） HfO2/SiO2 mirror coatings are investigated using a commercial 50-fs, 800-nm Ti：sapphire laser system. Precise morphologies of damaged sites display strikingly different features when the samples are subjected to various number of incident pulses, which are explained reasonably by the standing-wave field distribution within the coatings. Meanwhile, the single-pulse laser-induced damage threshold of the ＂standard＂ mirror is improved by about 14% while suppressing the normalized electric field intensity at the outmost interface of the HfO2 and SiO2 layers by 37%. To discuss the damage mechanism, a theoretical model based on photoionization, avalanche ionization, and decays of electrons is adopted to simulate the evolution curves of the conduction-band electron densitv during r^ulse dHratian.展开更多
基金The work is supported by the National Natural Science Foundation of China （No. 51005085）.
文摘On-line temperature monitoring of plasma sprayed coating is presented, which is based on IR pyrometery combined to robot trajectories. Temperature fields of the substrate before spraying and the deposited coating when the damage happens are taken to investigate the temperature fluctuation information. Experimental results demonstrate that coating damage always occurs in the temperature transition area of the substrate from the higher to the lower, as well as the higher temperature area. The temperature difference between the peak and the mean of the relevant regions is beyond 30 - 50℃ or even higher. This case provides the omen of coating damage and the focusing scopes for the process control of coating temperature in plasma spraying
文摘Single-pulse and multi-pulse damage behaviors of ＂standard＂ （with A/4 stack structure） and ＂modified＂ （with reduced standing-wave field） HfO2/SiO2 mirror coatings are investigated using a commercial 50-fs, 800-nm Ti：sapphire laser system. Precise morphologies of damaged sites display strikingly different features when the samples are subjected to various number of incident pulses, which are explained reasonably by the standing-wave field distribution within the coatings. Meanwhile, the single-pulse laser-induced damage threshold of the ＂standard＂ mirror is improved by about 14% while suppressing the normalized electric field intensity at the outmost interface of the HfO2 and SiO2 layers by 37%. To discuss the damage mechanism, a theoretical model based on photoionization, avalanche ionization, and decays of electrons is adopted to simulate the evolution curves of the conduction-band electron densitv during r^ulse dHratian.
