Method for preparing high-temperature self-lubricating coating by fast induction and thermal sintering

Abstract

The invention discloses a method for preparing a high-temperature self-lubricating coating by fast induction and thermal sintering, which is particularly suitable for preparing heat resistance, abrasion resistance and self-lubricating coating materials of the surface of a service metal part in the condition of high temperature. In the method, a composite powder is prepared by carrying out rubber-surfaced rolling and ball milling on powders of Ni, Cr, Cr2O3, BaF2, CaF2 and Ag for 24-96h; the composite powder is paved on an Ni Cr alloy matrix and is treated by cold pressing with the cold pressing pressure of 300-400MPa and the pressure keeping time of 10-15min, thereby obtaining a coating; and finally, the coating after cold pressing is treated by hot pressing and sintering in an intermediate frequency induction hot pressing and sintering furnace, the temperature is controlled at 900-1000 DEG C for 10-30min in the process of sintering and then fast rises to 1100-1200 DEG C for 5-15min in the pressure of 9-20MPa, and the high-temperature self-lubricating coating materials can be formed on the Ni Cr alloy matrix.

Description

technical field The invention belongs to the field of high-temperature-resistant lubricating materials, and relates to a method for preparing a high-temperature self-lubricating coating by rapid induction thermal sintering, and is particularly suitable for preparing a heat-resistant and wear-resistant self-lubricating coating material on the surface of metal parts serving under high-temperature conditions. Background technique Elastic foil aerodynamic bearings are one of the key components of high-performance fighter jets and large aircraft. The technical difficulty lies in solving the lubrication between the journal and the foil during the start-stop phase or overload. Therefore, the US NASA Green Center successfully developed a high temperature resistant (room temperature-650°C) self-lubricating PS304 coating (US Patent US 5866518) in 1995-1997. The coating is based on NiCr (80 / 20) alloy, with Cr 2 o 3 As the strengthening phase, Ag and BaF 2 / CaF 2 The (62 / 38) eutecti...

AI Technical Summary

Problems solved by technology

However, when this process is used to prepare high-temperature lubricating coatings, sintering at 1000-1200°C for 1-3 hours not only dissolves the coherent strengthening phase of the superalloy matrix material into the matrix, but also causes the grains of the alloy to grow significantly when the sintering temperature is high. As a result, the mechanical properties of the base alloy are greatly reduced at high temperatures, which makes the superalloy journals with lubricating coatings prepared by this process unable to be used at high temperatures