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Thermal analysis of materials, components and processes with a high capacity macro-thermobalance
Thermische Analyse von Werkstoffen, Komponenten und Prozessen mit einer sehr leistungsfähigen Makrowärmebilanz
Key processes during the production of hard metals and other powder metallurgical products are drying, dewaxing and outgassing. Methods of thermal analysis are used for understanding these processes. There are different possibilities in order to transfer the results from small material samples usually used in thermal analysis to the industrial process. One of them is the comparison of results of conventional methods with results of macro devices. The application of a new Macro- Thermobalance is presented. With the investigation of the behaviour of components instead of small material samples additional results are gained in respect to the influence of gas diffusion paths (component dimensions). It is shown that greater component thickness shifts the dewaxing process to higher temperatures. Such process knowledge is very important for a high product quality (avoidance of disturbance of the carbon balance or of cracks). The Macro-Thermobalance was modified in order to meet thedemands for the investigation of such processes. First of all the handling of high amounts of evaporated organic aids was mastered. Results of investigating ceramics and hardmetals are given and the potentials of the high capacity Macro-Thermobalance are discussed.
The results for the drying, debinding, outgassing and sintering behaviour of large samples or parts measured in a macro-thermobalance allow the formulation of application oriented conclusions Up-scaling of the results of experiments with small samples in conventional TA equipment to large samples (Mass up-scaling factor up to 1 : 10 000) Optimization of temperature-time profiles in technical aggregates (debinding of highly plasticised parts, simulation of real atmospheres, minimization of residual carbon content, sintering of large samples, kinetic analysis) Contribution to the optimized construction of aggregates for debinding, outgassing, sintering and burning processes.