Design, modeling and construction of a temperature-controlled vacuum furnace

Abstract

The work presents an investigation that encompasses the concept, development, and mathematization of a vacuum furnace system with temperature control as a function of time. The project aims to achieve a wide range of temperatures from room temperature in a short period of time, using a mechanical device as the basis of the furnace. To raise the temperature of the system from the initial temperature to the desired temperature, a helical tungsten resistor is used inside the furnace. The resistor has a helical geometry and plays the role of the system’s heating component. The furnace was built to treat thin carbon films produced using the sputtering technique, with the aim of producing homogeneous single-layer graphene. To heat the system, use was made of a physical phenomenon that uses electromagnetic waves emitted by the resistor to propagate heat through the system. By pre-calculating the characteristics of electromagnetic waves, heating is induced since these waves can propagate even in vacuum conditions (radiation). The heating process begins when this component is subjected to a specific power, representing the energy radiated per second. The rate of change of temperature in relation to time was formulated mathematically, represented graphically by means of simulations and numerical modeling, and validated experimentally to verify the conformity of the model, ensuring its accuracy. In addition, it is important to note that, although there are various heating devices (furnaces), it was essential to conduct a specific study of a device capable of performing an effective job in terms of thin film treatment, with the ability to reach desired temperatures in short time intervals, with the atmosphere controlled in terms of both pressure and composition. This work shows the roadmap for the construction of a vacuum furnace for research use (small dimension). The vacuum furnace built showed sufficient results for the heat treatment of small portions of materials, with temperature control, with all the important steps for its construction and characterization considered in detail, with extensive discussion.