| 摘要 |
A metal sheathed heating element comprises a metal sheath of stainless steel or nickel chromium alloy, a barrier layer of cerium oxide, aluminium oxide or nickel oxide, and an outer coating of gold or gold alloy containing platinum, palladium or rhodium. The gold coating is from an organo compound solution containing a gold sulforesinate or a gold mercaptide, or other "liquid bright gold" composition or "bright white gold" composition. The refractory oxide layer is applied by vacuum deposition, flame spraying or electro-plating, or from an organo compound of the metal (see Division B2). A specific example includes gold tert-dodecyl mercaptide.ALSO:A refractory oxide layer is applied to a metal sheathed heating device, (see Division H5), by preparing a solution of an organo compound of the metal in an organic solvent, spraying or brushing the solution over the metal sheath as a thin layer, and firing the sprayed-on layer in air at 300 DEG -800 DEG C to drive off the organic matter and to convert the organo metal compound to its respective oxide. Suitable oxides are cerium oxide, aluminium oxide or nickel oxide, and the coating is 200-1000 Angstrom units in thickness. A specific example uses cerium resinate solution and another example uses aluminium resinate solution. |
