The study aims to develop an infrared temperature-sensing system by applying to thermal radiation theory. The system consists of an optic unit, a photodetector, and an electronic unit. This system detects thermal radiation at 1310 nm wavelength, the temperature range of the system is 600~4000¢J, rise time 2£gs, spatial resolution 400£gm. The calibration was performed in the temperature low at 1200¢J by using a K-type thermocouple that can gain between temperature and output voltage relations, but beyond the temperature 1200¢J applying to Planck¡¦s law as calculate to predict. In the calibrated temperature range, the measurement error is ¡Ó80¢J for the low temperatures and ¡Ó20¢J for the high temperatures. The system was used to measure temperature variation during Nd:YAG pulse laser welding process. Experiments ware performed with stainless steel plates as specimen radiation by a laser pulse of 7ms duration time and various energy in the rang of 1245~5313mJ. The experimental results show the feasibility of the infrared temperature-sensing system in application of Nd:YAG pulse laser welding process.

Les techniques de frittage ultrarapide « naturel » (sans charge) comme le frittage par micro-ondes ou par induction présentent de nombreux avantages. Toutefois, le développement de ces techniques passe par une compréhension et une maitrise des mécanismes mis en jeu. A la fois similaires et complémentaires, ces procédés de chauffage-frittage ont été étudiées par une approche expérimentale afin d’approfondir les connaissances dans le domaine du Frittage Ultrarapide Naturel (FUN). Au cours de cette thèse, l’étude du frittage par micro-ondes de composites céramiques Al2O3-(Y)ZrO2 (3 à 40%vol.) a été menée parallèlement à celle du frittage par induction d’une poudre métallique micronique de nickel. La démarche expérimentale adoptée a consisté à réaliser des expériences de frittage à vitesses de chauffage imposées (de 25 à 1000°C/min) sur ces matériaux modèles et des pièces de petites dimensions, en se référant aux comportements en frittage conventionnel tant au niveau macroscopique qu’au niveau microscopique. / The techniques of ultrafast pressureless sintering as microwave or induction sintering offer manyadvantages. However, the development of these techniques requires an understanding and a control ofthe mechanisms involved. Both similar and complementary, these processes of heating-sintering havebeen studied by an experimental approach to increase knowledge in the field of Ultrafast PressurelessSintering.In this thesis, the study of microwave sintering of Al2O3-(Y)ZrO2 composites has been conductedin parallel with induction sintering of a submicronic nickel powder. The experimental approach usedconsisted in carrying out sintering experiments at imposed heating rates (from 25 to 1000°C/min) onchosen materials and small parts, referring to conventional sintering behavior at the macroscopic andmicroscopic scale.