Continuous Coating Process for Magnet Wire Insulation

In recent decades, advancements in electronic components have led to devices that generate significantly more heat per unit area. The processes by which waste heat is removed are less efficient, and the system must operate at higher temperatures. Magnet wire is a key component in many of these devices, and the durability of the insulating coating is critical to operation at elevated temperatures. Additional stresses on the wire insulation also come from the use of high-frequency, pulse-width-modulation control schemes. The integrity and lifetime of the magnet wire coating is therefore directly related to system performance and reliability. In previous work, Ultramet developed a rapid, low-cost method of applying oxide, nitride, and carbide interface coatings to carbon and silicon carbide fibers at low temperatures (as low as 100°C) through ultraviolet-enhanced chemical vapor deposition (UVCVD). Ultraviolet energy is used to decompose coating precursor gases at much lower temperatures than when thermal energy is used alone. The low temperature process has clear advantages over alternative coating methods because it is not line-of-sight and therefore can uniformly coat intricate shapes such as individual fine fibers. In this project, Ultramet will extend the current technology by applying BN coatings as insulation on magnet wire. The UVCVD process will also be transitioned from batch to continuous deposition, which will further reduce the cost of the coating process. The continuous process will also have increased manufacturing capabilities because it is not limited by downtime between batches or by reactor size.