NANO-MICROCOMPOSITE AND COMBINED COATINGS ON Ti-Si-N/WC-Co-Cr/STEEL AND Ti-Si-N/(Cr_3C_2)75-(NiCr)25 BASE: THEIR STRUCTURE AND PROPERTIES

摘要

Two types of nano-microcomposite coatings Ti-Si-N/WC-Co-Cr and Ti-Si-N/(Cr_3C_2)_(75)(NiCr)_(25) of 160 to 320μm thickness were manufactured using two deposition technologies: cumulative-detonation and vacuum-arc deposition in HF discharge. The combined coatings restored worn areas of tools and demonstrated high corrosion and wear resistance, increased hardness, elastic modulus, and plasticity index. The composition of top coating changed from Ti = 60at.%, N a 30at.%, and Si≈ 5at.% to N = 20at.% and Ti - the rest. The first series of coatings indicated the following phases: (Ti, Si)N and TiN for thin coating and WC, W_2C for thick one. The second series indicated (Cr_3Ni_2), pure Cr, and little amount of Ti_(19)O_(17) (in transition region) for thick coating and (Ti, Si)N, TiN for thin one. For the first series, grain sizes reached 25nm, hardness was 38GPa, elastic modulus E=(370±32)GPa, and plasticity index H/E=0,11-0,12 For the second series, grain sizes were 15nm, hardness essentially exceeded 42GPa ± 4GPa, elastic modulus E=(425+38)GPa, and plasticity index H/E=0,12-0,13 Corrosion resistance in salt solution and acidic media increased and cylinder-surface friction wear decreased.