HVOF And HVAF Coatings Are Reliable Sealing Solutions
HVOF coatings, as well as HVAF coatings, are being used in industries of all kinds, all over the world. The reason for that is simple. They work. They help protect against corrosion and erosion while being some of the most reliable sealing solutions in existence. Coatings such as chrome used to be both reliable and desirable. But today’s alternatives using new combination processes (HVOF and HVAF) are proving effective and affordable.
What’s the Problem with Chrome?
Particular problems have been presented by rods that have received hard chrome plating. One of the issues is the production of occupational carcinogens such as hexavalent chromium compounds. To eliminate workplace carcinogens such as these, the HCAT (Hard Chrome Alternate Team) was formed by the United States government in 1996. Tons and tons of research and development went into finding an alternate coating that could be used for, among other things, the sealing process.
Seals and Systems That Need Sealing
What comes to mind when you think about seal systems and seals? Compliant materials and elastomers, right? The sealing surface, however, though the backbone of the sealing system, is seldom thought of. Where elastomeric members are concerned, numerous changes have been made. With the sealing surface, however, alterations are also occurring. These latter changes have everything to do with application methods and materials.
Benefiting the hard chrome industry, one notable change will be highly useful by rework shops and for repairs including servicing hydraulic pistons and cylinders, landing gear, gas and oil drilling machinery, heavy equipment, pulp and paper mill roles, etc.
HVOF Coatings to the Rescue
A high energy process, the HVOF system was focused on by the above-mentioned project as a suitable thermal spray process to be used as an alternative to chrome.
A group of coating processes are covered by thermal spray in which nonmetallic materials or finely divided metallic materials are deposited in a semi-molten or molten condition, forming a coating. Coating stock can come in the form of molten, wire, ceramic rod, powder materials. Different thermal spray processes are distinctive and can include HVAF (high velocity air/fuel), HVOF (high velocity oxy/fuel), plasma, powder flame, wire flame, and wire arc.
What’s So Special About These Alternates?
The variety of coating materials that are available gives thermal spray coatings a significant advantage. Specific applications use materials such as the following:
- Metals
- Stainless steels
- Tungsten carbide cobalt chrome
- Tungsten carbide nickel chrome
- Chrome carbide
Why is that important? A variety such as this allows the process to be tailored to applications specific to various operating environments. For example, electrolytic hard chrome may not be considered to perform well under certain operating environments, so an alternative would be preferred. Fortunately, as you can see, there are a significant number of other choices.
Who Uses HVOF Coatings?
Where aircraft are prepared – in military depots and elsewhere in the aircraft industry – HVOF is frequently used. For example, landing gear cylinders receive an HVOF coating as new aircraft landing gear are designed. On other essential parts and systems, the same technology is used: i.e., helicopter dynamic components, propeller hubs, aircraft hydraulic actuators, engines, and more.
HVOF coatings demonstrate less corrosion and wear, and last longer in addition to eliminating the carcinogen problem mentioned earlier.
All of that said, many industries (aside from aviation and the military) put HVOF coatings to good use each and every day.
Where to Turn For HVOF Coatings
At A&A Coatings, we specialize in HVOF, HVAF, and all other types of thermal spray coatings. To apply chrome alternative coatings and other protective coatings, we utilize a number of thermal spray processes. We employ the latest technology, and base our chosen materials on the most recent, proven scientifically researched solutions. Call or email us today to find out more about utilizing HVOF/HVAF for your coating needs!
