Tribotechnical properties of coatings on titanium alloys

We compare the antifriction properties of different types of coatings on titanium alloys under conditions of boundary friction as applied to parts of the hydraulic cylinders of an aircraft. We show that gasthermal titanium carbide coatings cladded with nickel and with both copper and nickel have better antifriction characteristics than ones obtained by chrome electroplating, nickel chemoplating, thermooxidation, anodization, etc. Kiev International University of Civil Aviation; J.S.S.T.C. “Antonov,” Kiev. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 34, No. 2, pp. 55–62, March–April, 1998.     

Fatigue characteristics of VT22 titanium alloy with wear-resistant coatings

We study the influence of wear-resistant gas-thermal plasma and ion-plasma nitride coatings, diffusive electrochemical treatment, and vacuum nitriding on the fatigue resistance of specimens made of VT22 titanium alloy. The experimental results demonstrate that the wear-resistant hard coatings decrease the fatigue limit, whereas the procedure of sand-blasting increases the fatigue resistance of the alloy. Unlike diffusive coatings, plasma coatings suffer cracking and exfoliate from the surface of titanium alloy, which reveals their insufficient adhesion and high stiffness. The obtained results are quite urgent for the aircraft industry, where the VT22 alloy is extensively used. __________ Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 42, No. 6, pp. 119–122, November–December, 2006.     

Fatigue Characteristics of Aircraft Materials with Ionic-Plasma Coatings

We study the effect of mono- and multilayer ionic-plasma titanium-nitride-titanium coatings on the fatigue strength of aircraft materials: 30KhGSA structural steel, 07Kh16N6 stainless steel, and VT22 high-strength titanium alloy. We show that the effect of ionic-plasma coatings on the fatigue limit depends on both the kind of material of the substrate (base) and the technology, i.e., the structure of the coating itself. The positive influence on the fatigue of the base of multilayer coatings as compared with monolayer is connected with the stresses arising in the course of spraying.