Search Results for atom

Field ion microscopy (FIM) can be used to study the three-dimensional structure of materials, such as metals and semiconductors, because successive atom layers can be ionized and removed from the surface by field evaporation. The ions removed from the surface by field evaporation can be analyzed chemically by coupling to the microscope a time-of-flight mass spectrometer of single-particle sensitivity, known as the atom probe (AP). This article describes the principles, sample preparation, and quantitative analysis of FIM. It also provides information on the principles, instrument design and operation, mass spectra and their interpretation, and applications of AP microanalysis.

Atomization is the dominant method for producing metal and prealloyed powders from aluminum, brass, iron, low-alloy steels, stainless steels, tool steels, superalloys, titanium alloys, and other alloys. The general types of atomization processes encompass a number of industrial and research methods. This article describes the key process variables and production factors for the industrial methods: two-fluid, centrifugal, vacuum or soluble-gas, and ultrasonic atomization. It also reviews the effect of atomization methods and process variables on key powder characteristics such as the average particle size, particle size distribution or screen analysis, particle shape, chemical composition, and microstructure.