Study Of Microwave Sintering Oven And Power Supply For Driving The Microwave Sintering System

Microwave sintering is an emerging technology that receives extensive attention in recent years. It is an important process in the preparation of functional ceramics. In order to get high-performance functional ceramic components, sintering process should closely integrate with microwave sintering system. The key of microwave sintering is the automated microwave sintering system, and the system here is designed for this purpose.The system uses switching power supply technology to drive the magnetron and uses ATmega16 microcontroller as the core circuit. The switching time is adjusted by changing the duty cycle of PWM waveform. The adjustment process is done by ATmega16 microcontroller. MCU and host computer communicates through the serial port. It also captures the data obtained from sintering process and draws sintering curves. The temperature of the samples in the reaction chamber is measured by Infrared Thermometer. The MCU uses PID algorithm to make data processing, and adjusts the output of the magnetron by adjusting the PWM waveform duty cycle. The control circuit is also used to get the temperature data which is measured by the infrared thermometer, and sent it to the host computer via serial port.The host computer software is developed by Visual C++, it has the function of configuring serial port, providing users with curve settings interface, setting the data and transmitting it to the microcontroller through the serial port. It receives real-time temperature data from the microcontroller, draws sintering curve which could be used in future studies.The static parameters of zinc oxide varistors sintered by microwave sintering system are measured, including leakage current, breakdown voltage and non-linear coefficient. The clamping voltage ratio and the surge current withstanding performance are also tested. The characteristics are compared between microwave sintered samples and traditionally processed samples. The PTCR is sintered with the microwave sintering system. The size, common resistance, and the Resistance-Temperature of the PTCR are measured. The results show that the microwave sintering system can shorten sintering time and performance of the sample is good.