초록 ▼

A method for improving the wear characteristics and corrosion resistance of a metal surface having the basic steps of: A. case hardening the metal surface by placing the metal in a fluidized bed and exposing it to a first atmosphere of nitrogen, ammonia and natural gas at a temperature between about

A method for improving the wear characteristics and corrosion resistance of a metal surface having the basic steps of: A. case hardening the metal surface by placing the metal in a fluidized bed and exposing it to a first atmosphere of nitrogen, ammonia and natural gas at a temperature between about 750°F. and about 1200°F. for a period between about 1 and about 5 hours, followed by exposure to a second atmosphere containing nitrogen and water at a temperature between about 750°F. and about 1200°F.; B. coating the metal with an aqueous coating composition consisting essentially of a polymeric additive and water; and C. allowing the coating composition retained on the metal to cure for a period between about 2 and about 48 hours.

대표청구항 ▼

A method for improving the wear characteristics and corrosion resistance of the surface of a metal comprising the steps of: A. case-hardening the surface of pieces of the metal, the case hardening step comprising: 1. immersing the metal pieces in a fluidized bed of particulate material at a temperat

A method for improving the wear characteristics and corrosion resistance of the surface of a metal comprising the steps of: A. case-hardening the surface of pieces of the metal, the case hardening step comprising: 1. immersing the metal pieces in a fluidized bed of particulate material at a temperature between about 750°F. and about 1200°F.; 2. introducing a first gaseous atmosphere into the bed, the first gaseous atmosphere selected from the group consisting of ammonia, nitrogen and natural gas while maintaining the temperature between about 750°F. and about 1200°F. 3. maintaining the metal pieces in contact with the first gaseous atmosphere for a time period between about 1 and about 5 hours. 4. promptly contacting the metal pieces with a second gaseous atmosphere containing nitrogen and water while said pieces are immersed in a fluidizing bed of particulate material at a temperature between about 750°F. and about 1200°F. 5. maintaining the metal pieces in contact with the second gaseous atmosphere for a time period between about 30 minutes and about 90 minutes; and B. subsequent to the case-hardening step, contacting the case-hardened metal piece with an aqueous coating composition consisting essentially of: 1. a phosphating oil; 2. an aminofunctional alkylpolysiloxane or aminofuctional polyalkylsiloxane; and 3. water; C. allowing the coating composition retained on the metal piece to cure for a period between about 2 hours and about 48 hours.