METHOD TO PRODUCE A COMPOSITE LAYER RESISTANT TO GALLING, ABRASION, CORROSION, ALTERNATING-STRESS FATIGUES, AND COMPOSITE LAYER PRODUCED BY THIS PROCESS

摘要

1. A composite layer for covering a base substance in order to resist at the same time seizing, abrasion, fatigue caused by alternating stresses, and corrosion, characterized in that it is made up of at least three successive unitary layers with a base of a transitional metal (M) and a non-metallic component referred to as n on-metal (m), these unitary layers being constituted in a proportion greater than 70 % by combinations betwen the transitional metal (M) and the non-metal (m), whilst in addition the first two unitary layers from the external surface are composed respectively of two compounds Mmx of the same transitional metal (M) and of the same non-metal (m), the composition of the two said unitary layers differing only by the value of the index x in each : - the external unitary layer having a hardness greater than 1 000 Vickers - the unitary layer immediately below the external layer having a hardness greater by at least 500 Vickers than that of the said external unitary layer.