微波加热Mn-Zn铁氧体粉末压坯的微观机制及特点分析

采用频率为2.45 GHz的微波对Mn-Zn铁氧体粉末压坯进行加热,详细探讨微波加热过程微波场与电介质作用的微观机制以及软磁铁氧体在微波场中的电、磁损耗机理;探讨Mn-Zn氧体粉末压坯在微波场中加热的特点以及微波场E、磁导率μi、介电常数εr等对微波加热温度的影响。Mn-Zn铁氧体是磁性混合介质,在微波场中被加热的根本原因是Mn-Zn铁氧体粉末压坯在微波场作用下,微波电磁能以损耗的方式转化为热能对材料进行加热,这种损耗主要是介电损耗、磁损耗;影响损耗的主要电场因素包括微波电磁场的强度和频率,在特定频率(2.45 GHz)的微波场中,微波功率是Mn-Zn铁氧体加热烧结温度的主要影响因素,功率改变,加热烧结曲线随着变化;影响损耗的材料因素主要是磁导率μi、介电常数εr,两者随温度、频率变化。

Mechanism and Characteristics of Mn-Zn Ferrite Powder Compacts Heated by Microwave

The Mn-Zn ferrite powder compact is heated by microwave with a frequency of 2.45 GHz. This essay illustrates the micro-mechanism of the interaction between microwave field and dielectric, elucidates the mechanism of soft-magnetic ferrite electromagnetic loss in microwave field, and discusses the characteristics of Mn-Zn ferrite powder compact when heated by microwave, as well as some factors such as microwave fieldE, dielectric constantεr , permeabilityμi, etc, which influence the heating temperature. Mn-Zn ferrite is a magnetic mixed media, and the basic reason for Mn-Zn ferrite powder compacts can be heated in microwave field is that the microwave electromagnetic energy can convert into heat along with energy loss. The energy loss mainly includes dielectric loss and magnetic loss, and the main factors influence the energy loss are microwave electromagnetic field intensity and its frequency.In a particular microwave field (2.45 GHz), the power of the microwave is the main influence factor of the sintering temperature , when the power of microwave changes, it leads to the change of the heating sintering curve. The material influence factors of the energy loss for Mn-Zn ferrite are permittivityεr and permeabilityμi,both chang with temperature,and frequency.