| abstract |
PROBLEM TO BE SOLVED: To rust a partner metal in a humid environment, which is a problem when using calcium sulfate, which is non-black, inexpensive, easily available, and has excellent lubricating performance as a solid lubricant, on the surface of a metal material such as steel. Providing means to improve easy characteristics. A solid lubricant comprising a calcium sulfate crystal whose crystal surface is coated with a calcium compound that is hardly soluble or insoluble in water. [Selection] FIG. |