ALUMINUM OXIDE COATINGS DEPOSITED BY THE CCDS2000 DETONATION SYSTEM
V. Yu. Ul’yanitskii, I. S. Batraev, D. K. Rybin, A. A. Shtertser
Lavrentyev Institute of Hydrodynamics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: detonation system, detonation spraying, aluminum oxide coating, electrical insulation, adhesion, microhardness, abrasive wear resistance, erosive wear resistance
Abstract
This paper describes the CCDS2000 detonation coating system and demonstrates its capability for depositing electrically insulating and wear-resistant aluminum oxide coatings. The dielectric strength of the coatings exceeds 25 kV/mm within a thickness range of 50-300 μm. The coatings exhibit an electrical resistivity ρe > 2.67 × 1013 Ω·cm at 20°C and a relative humidity of up to 59%. A further increase in humidity caused a sharp decrease in ρe by 2-3 orders of magnitude. The coatings exhibit adhesion to a steel substrate of 60-70 MPa, a microhardness value HV0.1 = 1522-1655, and a porosity of 0.35-1.00%. Evidently, the C2H2 + 2O2 detonation mixture is optimal for obtaining electrically insulating coatings, whereas the 0.69C2H2 + 0.53C3H6 + 2.51O2 mixture yields the best wear resistance. The use of the dual-fuel mixture results in a fourfold increase in abrasive wear resistance and a 34% improvement in erosive wear resistance.
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