NANOSCALE PARTICLES, AND USES FOR SAME

摘要

Nanoscale particles and powders are made from a starting material, including larger-size starting particles and solid targets. Various techniques are disclosed all of which generally involve heating and decomposing the starting material with an energy source selected from the group consisting of laser, electric arc, flame and plasma. The various techniques disclosed herein all exhibit a high throughput and a nearly instantaneous rate of production of nanoscale powders for a variety of applications. In certain of the embodiments, cooling is required to prevent agglomeration of the nanoscale particles into larger (non-nanoscale) particles. The nanoscale particles are useful for painting, coating, joining, bonding, brazing, soldering, welding, etc. For example, thermal stresses normally associated with joining (e.g., brazing) may be alleviated by a low-temperature joining technique of the present invention. A low-temperature joining material is applied (as a paste, or as a powder spray, or as a tape, or as a paint, or as a putty) at the junction of two components desired to be joined together. Energy from a source such as a laser beam (for example an Nd:YAG or a CO2 laser) or by a flame, arc, plasma, or the like, is either "walked" along the joining material to react the entire amount joining material, or the joining material is self-sustaining and simply requires igniting a selected portion of the joining material by the energy source. In an exemplary application of the process, vanes are brazed to the bowl and/or to the shroud of an automatic transmission bowl (impeller or turbine) assembly, preferably using the low-temperature joining material. Systems for delivering the joining material and the energy are described. The fabrication of hollow vanes is described. The fabrication of shroudless bowl components, and stator components subsuming the function of the shroud are described.