Abstract: A method of measuring parameters of a particle includes providing a particle, wherein the particle has a first portion and a second portion. The process includes providing a column of photo-detectors including a first photo-detector and a second photo-detector, wherein the first photo-detector and the second photo-detector are sensitive to the same range of light frequencies. Light is projected from the particle onto the column of photo-detectors wherein the column of photo-detectors is oriented so the light from the first portion is projected onto the first photo-detector and light from the second portion is projected onto the second photo-detector. Light measured by the first photo-detector differs from light measured by the second photo-detector. The process further includes using the different first and the second photo-detector measurements to determine at least one from the group consisting of particle temperature and particle diameter.

Abstract: An improved automatic feedback control scheme enhances plasma spraying of powdered material through reduction of process variability and providing better ability to engineer coating structure. The present inventors discovered that controlling centroid position of the spatial distribution along with other output parameters, such as particle temperature, particle velocity, and molten mass flux rate, vastly increases control over the sprayed coating structure, including vertical and horizontal cracks, voids, and porosity. It also allows improved control over graded layers or compositionally varying layers of material, reduces variations, including variation in coating thickness, and allows increasing deposition rate. Various measurement and system control schemes are provided.

Abstract: A method of characterizing an electron beam is described, comprising providing a system including an electron gun having a steering coil. A material having a surface is also provided. An electron beam from said electron gun is directed to said surface. The directing includes providing a first current to the steering coil to direct the electron beam to a first point on the surface and then providing a second current to the steering coil to direct the electron beam to a second point on the surface. An imaging system is mounted for viewing said surface. An image is collected based on light emitted from the surface because of the electron beam directed at the first point and the second point. A light intensity is determined at the first point and at the second point.

Abstract: An improved automatic feedback control scheme enhances plasma spraying of powdered material through reduction of process variability and providing better ability to engineer coating structure. The present inventors discovered that controlling centroid position of the spatial distribution along with other output parameters, such as particle temperature, particle velocity, and molten mass flux rate, vastly increases control over the sprayed coating structure, including vertical and horizontal cracks, voids, and porosity. It also allows improved control over graded layers or compositionally varying layers of material, reduces variations, including variation in coating thickness, and allows increasing deposition rate. Various measurement and system control schemes are provided.