The potential for material processing by microwave energy
This paper presents the potential applications for material processing by microwave energy which is electromagnetic waves that penetrates material and cause its molecules to rotate and generate heat. In this paper, potential uses of microwave energy in iron and steel making processes will be discussed in detail. Actually, microwave energy has been in use for various applications for over half century. One of the most well known applications is drying and cooking of food. Currently, industrial uses of microwave energy include direct-reduced iron making, wood processing, sintering, coke making, and so on. And moreover, CO2 and CH4 can be decomposed by super heating effect of microwave energy which can also be called as high temperature plasma furnace. In conventional heating processes, the materialpsilas surface is heated first and then the heat moves inward, while the material is heated the entire volume at about the same time, in microwave heating processes. Microwave heating method can be used in addition to conventional heating techniques to enhance the reaction of the material processing.
Microwave Application in Carbothermic Reduction of Iron Ores
Reduction of hematite fines and magnetite concentrates containing carbon using microwave energy was investigated. The reduction rate was found to be very rapid under all conditions employed. The nature of the ore mineral and flux (lime and limestone) did not influence the reduction but the nature of carbon had an effect, with charcoal being superior to coke.Microwave reduction is a highly non-isothermal process and bearing this in mind, the effect of temperature on reduction was exponential. Difference between the reduction of identical samples with microwave and conventional heating (1000°C) was remarkable–in favour of microwave heating.
Failure analysis for poor solderability of Au surface of PCB
Nonwetting is one of the common problems and is always rejected in electronic assemblies. ENIG pads of a PCBA exhibited nonwetting after lead-free reflow soldering. With the aid of stereomicroscope, SEM&EDS and XRF, a series of analysis was performed. And after visual inspection, surface and cross section analysis, thickness measurement and solderability test, it can be inferred that oxidation of plating surface was the main reason for nonwetting, and corrosion in Ni plating caused an adverse impact on solderalibity.