There is a growing demand for a cost-effective alternative to electrolytic hard chrome coatings in corrosive environments.
The market is seeking environmentally friendly, long-lasting tungsten carbide coatings or affordable stainless-steel coatings.
EWSLLP HVAF technology and equipment offer a solution for replacing hard chrome with impermeable, hard, and ductile coatings that are budget-friendly and easy to apply.
Several researchers have highlighted that HVAF coatings exhibit significantly longer performance compared to electrolytic hard chrome, all at the same or even lower cost.
How do we achieve thermal spray coatings as economical as hard chrome plating?
We apply thin gas impermeable coatings with low roughness to eliminate the need for grinding. We apply coatings rapidly. We have the systems to coat both outer and internal surfaces. We have developed the thermal spray coating technology to ensure successful application without failures.
The High-Velocity Air Fuel (HVAF) process has proven to be a highly competitive, one of the ideal hard chrome plating alternatives and environmentally friendly solution.
HVAF carbide coatings surpass competitors in HVOF and EHC in terms of corrosion protection, wear resistance, and production cost.
The high velocity of the in-flight particles, exceeding 1,000 m/s (3,280 ft./sec.) in our HVAF Thermal Spray process, facilitates the production of extremely dense coatings with exceptional bond strength.
Furthermore, the low combustion spraying temperature (1,960-2,010°C | 3,560-3,650°F, depending on fuel gas) and gentle particle heating contribute to minimal feedstock phase transformation and nearly nonexistent elemental depletion/decomposition of the in-flight particle.
Additionally, the HVAF Coating process's substitution of pure oxygen (used in HVOF) with air significantly reduces the oxide content in the coatings, a highly desirable characteristic for high-performance coatings.
HVAF and HVOF technologies have been integrated into a unified system, HVAF/HVOF, which provides the industry's highest spray rates in either mode.
This versatile system delivers economically sound, high-quality coatings through user-friendly and reliable equipment.
The HVAF portion of the system applies tungsten carbide coatings following HVOF specifications, achieving a spray rate that is five times faster and at half the cost.
It deposits coatings in compliance with standards such as SAE AMS 2447, 2448, or proprietary specifications. HVAF/HVOF coatings meet all existing HVOF specifications. Our Convertible HVAF/HVOF system seamlessly operates in existing HVOF or plasma spray booths, providing the choice to spray superior HVAF or HVOF coatings.
The Hybrid Convertible HVAF-HVOF Thermal Spraying Equipment includes an HVAF/HVOF Spray Torch, a Control console equipped with a PLC and an industrial mobile computer, a Powder feeder, a Gas vaporizer, and an Optional grit feeder for HVAF grit blasting.
Flash Carbide, inspired by the concept of Flash Chrome, represents a thermal spray coating applied swiftly with minimal preparation and finishing, thanks to advancements in gun technology.
These coatings have the potential to surpass the performance of hard chrome plating in specific scenarios – making it one of the preferred hard chrome replacements.
HVAF technology contributes to the creation of coatings that are not only harder but also exhibit superior bonding.
The growing demand for a cost-effective alternative to electrolytic hard chrome coatings in corrosive environments has fueled a need for environmentally friendly, durable options such as tungsten carbide coatings or affordable stainless steel coatings for Titanium parts.
Our HVAF technology and equipment offer a solution to replace hard chrome with coatings that are impermeable, hard, ductile, and cost-effective.
Numerous studies indicate that HVAF coatings outperform electrolytic hard chrome, providing longer-lasting results at a similar or lower cost.
Our approach involves thermal spraying thin gas impermeable coatings with minimal roughness, applied rapidly to both outer and internal surfaces.
Our developed technology ensures the application without failures, presenting a practical and economical alternative to hard chrome plating.
HVOF and HVAF are two thermal spray systems that utilize gas combustion. HVOF spraying integrates velocities exceeding 700 m/s along with moderate temperatures.
This method results in a highly dense coating (> 97%). Deposition rates can reach up to 9 kg/hour, with coating thicknesses ranging from 0.05 to 1 mm.
The service life of the part should not lead to excessive wear on the seal surfaces. Reciprocating motion should not adversely impact the seals themselves during contact with the part.
The application of the hard chrome replacement coating should not alter the material properties of the substrate, particularly causing heating that could induce the formation of the beta phase within the titanium crystalline structure.
The coating should also remain cost-effective. Customer-conducted tests, simulating operational conditions over several months, revealed longitudinal cracks in the coating, forming stress concentrations that led to crack propagation through the titanium alloy substrate.
As cracks extended through the substrate, it created a passage between two isolated fluid circuits, rendering the equipment unsuitable for continued use.
The fatigue life was approximately 2e5 cycles, significantly below the expected infinite fatigue life. These failures prompted the customer to specify an additional performance requirement.
Nickel-tungsten exhibits characteristics comparable to hard chrome, encompassing corrosion resistance, wear resistance, and hardness, even under high temperatures.
Additionally, it is non-toxic, rendering it a genuinely viable alternative.
The utilization of nickel-tungsten adheres to the concept of selective plating—a technique pioneered by SIFCO ASC for electroplating specific areas without the need for an immersion tank.
This hard chrome replacement process yields elevated hardness levels (660-690 HV, as plated) coupled with outstanding wear resistance (sliding wear rate ten times lower than hard chromium).
Moreover, the reduced surface roughness necessitates less refinishing compared to hard chrome deposits.
Piston rods in reciprocating compressors commonly experience wear in packaging seal areas. EWSLLP HVAF technology and equipment offer a solution to replace the existing coating on compressor rods with robust and ductile tungsten carbide coatings that are simple to apply.
Several studies have highlighted that HVAF WCCoCr coatings exhibit significantly longer durability compared to electrolytic hard chrome and HVOF carbide overlays.
In contrast to conventional electrolytic hard chromium plating, our coatings for compressor rods offer markedly superior wear resistance and eliminate the risk of hydrogen embrittlement in high-strength steels.
When employing HVAF systems for grit blasting as hard chrome alternatives, grit particles undergo acceleration to an extremely high velocity and simultaneous heating to over 1,200°C (2,200°F), significantly enhancing the cleaning and profiling efficiency of the process.
Surface preparation through HVAF grit blasting yields a tenfold increase in production rates with a hundredfold reduction in grit consumption compared to conventional grit blasting using compressed air.
This same setup is applicable for both blasting and thermal spray coating, utilizing the same gun and further reducing the time required for thermal spray coating jobs.
HVAF blasting also proves to be an effective method for the removal of hard coatings.
The HVAF High-Pressure Blast Feeder
The standalone HVAF High-Pressure Hot Blasting Grit Feeder is designed to supply grit media to HVAF guns.
The HVAF grit feeder comprises A set of 3 m (10') hoses/cables and a 4.5 m (15') powder hose. Standalone manual control unit. A 3.5-liter powder canister
HVAF hot blasting equipment is meticulously engineered to efficiently prepare superior-quality, clean metal surfaces, minimizing both time and grit blasting media consumption. Our diverse array of spray guns is tailored for various applications.
Whether operating each gun individually or simultaneously (as per request), our HVAF and HVOF systems deliver exceptional performance.
We provide two types of control consoles, along with a range of powder feeders and gas vaporizers.
We take pride in the design and manufacturing of our HVAF and HVOF thermal spray equipment.
Related article: What Is the Difference Between HVOF and HVAF Coatings?
Related article: What is HVOF? What are the key advantages of high-velocity oxyfuel coatings?
Related article: Why should you choose tungsten carbide over other metals?
Hard chrome possesses the advantage of being a singular material and deposition method suitable for a diverse range of applications.
Similarly, HVOF Thermal Spray Coating stands out as a single technology, offering a broad spectrum of materials that can be employed to attain the desired combination of properties for various purposes.
HVAF coating, or High-Velocity Air-Fuel, serves as a thermal spray process designed for depositing coatings to protect parts, vessels, and structures from abrasion, erosion, and corrosion. Its common applications include protecting against abrasion and erosion.
HVOF coating, or High-Velocity Oxygen Fuel, utilizes tungsten carbide coatings applied through a thermal spray process involving high kinetic energy directed into powder particles.
While these particles exhibit high energy, upon impact with the substrate, their velocity decreases to zero, and the kinetic energy is absorbed.
The hard chrome plating process involves the application of a chromium layer to a surface, enhancing corrosion and abrasion resistance, minimizing friction, and prolonging the lifespan of parts utilized in demanding wear conditions.
Coating thicknesses can vary widely, spanning from a few nanometres to several centimeters.
For instance, Titanium Zirconium (TiZr) coatings may have a thickness ranging from 1nm to 5nm, anodic films can vary between 0.5μm to 150μm, and paint coatings may reach thicknesses of up to a couple of millimeters.
The application of chrome plating can enhance surface hardness and durability, providing protection against corrosion and facilitating easier cleaning.
The process involves degreasing the surface to eliminate impurities and previous buildup. In certain cases, substrates or surface metals may require pretreatment to ensure optimal adhesion during the plating process.
Nickel-tungsten shares several comparable traits with hard chrome, such as corrosion resistance, wear resistance, and hardness—even at elevated temperatures.
Additionally, its non-toxic nature makes it a genuinely viable alternative.
In traditional hard chrome plating, a surface with a roughness ranging from 16 to 31 RMS (from 0.406 to 0.787 µm Ra) is necessary before the plating process.
Conversely, thin dense chrome plating demands a smooth surface finish before plating, as the application of chrome is minimal in this case.
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