The repair of damaged Ion Vapor Deposition Aluminum coatings on high strength steel aircraft components has generally required the use of brush plating with hazardous materials including cadmium. Inovati has developed a unique Al-Trans (aluminum-transition metal) coating using the Kinetic Metallization process that permits repairs of IVD-Al coatings on high strength steels. Originally the Al-Trans coating formulation was developed for commercial application on telecommunication equipment steel racks as an electrically conductive grounding strip with excellent corrosion resistance. Recent research was completed with NAVAIR to further develop this coating formulation and the Kinetic Metallization process for repair of IVD-Al coatings on aircraft components. This presentation will describe the KM repair process and the tests completed to qualify the repaired coatings. Inovati has recently developed a KM-Mobile Coating System with a handheld Spray Gun for the field repair of corrosion damaged magnesium and aluminum alloy aircraft components.

Cold spray produces superior coatings with many unique properties, which have led to many new applications of sprayed coatings. In a few applications, such as in-situ repair of aircraft body/engine parts, etc., a portable system is required. Though some portable low pressure (5 – 10 bars) systems are available, these systems have many limitations on coating materials and coating qualities. Recently a ‘Portable high pressure cold spray system’, called Kinetiks 2000, has been developed. Kinetiks 2000 system can operate at 400 °C max nitrogen temperature and 20 bars max gas pressure. A touch panel on the console is used to input and control the process parameters. A hand held gun with a filament heater and a gun body, mounted directly onto the heater, is used for manual spray. This system operates with two different powder hoppers. Coatings of many materials, including aluminum, copper, titanium, zinc, etc have been produced. Microstructural investigations of sprayed coatings have shown that good, strong, dense coatings with clean interfaces and strong bonding to various substrates can be produced. Experiments are continuing to quantify the process characteristics and record the properties of sprayed coatings.

Repair of damaged ion vapor deposition aluminum (IVD-Al) on aircraft components generally requires the use of brush plating with hazardous materials including cadmium. This paper describes a cold spray process that uses aluminum transition metals to make such repairs. The aluminum layers are applied with a handheld cold spray gun and tested according to JTP-2003 requirements for corrosion resistant coatings on steel components.

The German Army is using the Sikorsky helicopter Typ CH-53 G in the marine version, this means that the tail with the rear rotor can be folded sidewise in order to safe space during storage. During flight the fuselage is locked by two gear racks that slide in the bore hole of an aluminium housing. Due to the high friction during the movement of the steel racks the inner bore surface is damaged of up to 1 mm depth. In this paper the repair of this inner surface of the bore by arc-wire spraying is described. A special gun extension was developed so that the narrow bore (diameter 48 mm; length 400 mm) can be repaired. Preliminary test results with various materials are presented. Paper text in German.

Many components in helicopter dynamics systems depend on hard, wear resistant coatings for reliable performance. Component replacement times are currently limited by performance of these coatings in many cases. Thermal spray coatings have been evaluated for these applications to replace nickel and chromium electroplate. The effect of coatings on fatigue strength is quantified by a strain limit concept to reduce test requirements during development phase. Full scale bench testing and coupon wear testing were conducted to reveal large improvement in sliding and fretting wear resistance. A fine porosity network in thermal spray coatings, high hardness and high fatigue strength are shown to be the main contributors to improved wear performance. Thermal spray coatings also exhibited enhanced corrosion resistance in salt fog and crevice corrosion conditions. These data permitted implementation on several critical helicopter components.

High-velocity oxyfuel (HVOF) spraying is a viable alternative for hard chrome plating because of its excellent coating properties and substantially lower environmental pollution. Initial applications in ball valves, journals, and hydraulic cylinders on earthmoving equipment have proven successful. This paper discusses the advantages and disadvantages of HVOF spraying as an alternative to hard chrome plating for aircraft components and presents some of the early results of laboratory and in-service testing.