Coating & Thermal Spraying

From anti-corrosion coating to improved wear performance, thermal spray provides the perfect combination of high quality and cost effectiveness

Damaged surfaces can be repaired and faulty manufactured parts can even be given the right dimensions. In most cases, the surface can then be treated without difficulty. BOC prides itself in being able to offer the right coating solution using the ideal gas supply concept to deliver what its customers need.

"Thermal spraying comprises processes in which surfacing materials are heated to the plastic or molten state, inside or outside of the spraying gun/torch, and then propelled onto a prepared surface. The substrate remains unfused."  EN 657:1994.

Thermal spraying has become increasingly important, both in the manufacturing of new parts and in the repair of existing parts.  With increasing demands on component anti-wear and anti-corrosion protection, thermal spray is often the coating method of choice.  Its primary advantages are:

  • Numerous combinations of base material and coating material are possible.

  • High-quality materials can be used to improve the properties of the base material in a cost-effective way.

  • The flexibility of thermal spraying means that high-grade worn parts can be repaired keeping costs and downtime to a minimum.

There are a number of different thermal spray processes. Each has its own unique set of advantages which means that the correct choice of process is important to achieve the required finished properties.  Similarly, the choice of gas and supply system is critical to achieving the most effective coating process. 

Download our LINSPRAY® Thermal Spraying & High Performance Coating techniques brochure

HVOF thermal spraying solutions for chrome plating replacement in aerospace

Historically, aerospace manufacturers have utilised hexavalent hard chrome and nickel plating for flight critical applications. As the industry moves away from chrome, replacing it with aluminium through a High-velocity oxy-fuel (HVOF) thermal spraying process is considered the most viable, effective and efficient solution.

HVOF is an established thermal spraying process within the Aerospace sector, supporting manufacturing processes for landing gears, inner cylinders, pins, hydraulic rods, components, actuators, GTE’s and propeller hubs.  

HVOF using aluminium powder provides Aerospace manufacturers with improved performance in comparison to hard chrome plating, less wear and leakage, corrosion resistance plus is considered more environmentally friendly.

BOC’s technological developments and expertise can support manufacturers in the application of high-velocity oxy-fuel and plasma spraying through both specially shaped nozzle attachments and world-class Kerosene, Acetylene and Propane thermal spraying gases and gas mixtures.

Further development of high-velocity thermal spray methods has led to cold gas spraying where the surface material is propelled and plasticised, hitting the substrate and thus forming the combination with the basic material. This procedure is similar to explosion welding.

Plasma spraying solutions in orthopaedic implants

Plasma spraying is an established process adopted by medical device manufacturers (amongst many other industries) and is employed in conjunction with medical materials, to coat implants for insertion into the human body.

Whether knee, jaw, tooth root or implant, the process of plasma spraying is implemented utilising BOC gases such as argon, hydrogen, helium and nitrogen.

Cooling requirements in thermal spraying

During thermal spraying, the heat applied to the base material can be extremely high. This is particularly true of high-energy spray processes such as high-velocity oxy-fuel flame (HVOF) or plasma spraying.

When coating thin-walled substrates or substrates with very low thermal conductivity, or when using temperature-sensitive coating materials, overheating problems often arise if cooling is not employed. Differences in heat expansion rates can even cause the coating to flake off.

LINSPRAY® carbon dioxide (CO2) cooling solutions avoid the problem of overheating by effectively cooling the workpiece around the flame.

Find out how our advanced CO2 nozzles help to meet your thermal spraying cooling requirements

Watch our CO2 cooling solutions for thermal spraying video to find out more

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