METHOD OF FABRICATING A DARK HEATER

摘要

A refractory metal heater wire is first coated in conventional fashion with a first coating of insulating material, e.g., aluminum oxide. The coating is then dried in air at a temperature below which oxidation of the heater wire occurs for a time sufficient to completely remove all solvents from the first coating. Then, a second coating of a darkening material is applied over the first coating. The complete removal of solvents from the first layer prior to the second layer application step reduces penetration of the material of the second layer into the first layer.