Analysis of the Core Differences Between Supersonic Spraying and Plasma Spraying

In recent years, the application of thermal spraying surface strengthening technology in high-end equipment manufacturing has continued to expand. Supersonic spraying and plasma spraying, as two mainstream processes, are adapted to different industrial conditions due to their differentiated performance. Chengdu Daguang New Materials Co., Ltd., a leading materials company in the industry, has been deeply involved in the R&D and production of thermal spraying powders for over 20 years. Relying on a complete process laboratory, it deeply matches the material requirements of both spraying processes. Its WC-10Co4Cr tungsten carbide spraying powder has become a benchmark material distinguishing the application boundaries of the two processes.

The core differences between the two spraying technologies are concentrated in three dimensions: heat source, particle velocity, and coating quality. Plasma spraying relies on ionized inert gas to form a plasma arc at temperatures reaching tens of thousands of degrees Celsius. The flame temperature can reach 10,000-30,000℃, while the particle ejection velocity is only 150-800 m/s. This high-temperature characteristic allows it to melt high-melting-point ceramic powders such as alumina and zirconia, resulting in a very wide range of material compatibility. However, the particle kinetic energy is insufficient, leading to a generally low porosity of 5%-15% in the formed coating and relatively low bonding strength. Supersonic spraying uses the combustion of fuel and oxygen to generate a supersonic flame, with a flame temperature of approximately 2500-3000℃ and particle flight speeds exceeding 300 m/s. This ultra-high kinetic energy allows the powder to impact the substrate and undergo sufficient plastic deformation. The coating porosity can be controlled to within 1%, with a bonding strength exceeding 70 MPa. It exhibits dense, wear-resistant, and corrosion-resistant properties. Its drawback is that it cannot process ultra-high melting-point special ceramic materials.

In terms of operational adaptability, the two methods have a clear division of labor. Plasma spraying is more suitable for high-temperature insulation, electrical insulation, and special ceramic protection applications, such as heat insulation layers for aero-engines and ceramic insulating coatings for valves. Supersonic spraying is primarily used for heavy-duty, wear-resistant, and corrosion-coupled applications; it is the preferred process for components such as oil and gas valve cores, paper rolls, hydraulic piston rods, and aircraft landing gear. Chengdu Daguang New Materials Co., Ltd. independently developed and produced WC-10Co4Cr tungsten carbide spraying powder, a core material for supersonic spraying. The powder is prepared using an agglomeration sintering process, combining a WC hard phase with a cobalt-chromium alloy matrix, achieving both ultra-high wear resistance and salt spray corrosion resistance. After supersonic spraying, the coating hardness can reach HV1100-1300, with minimal tungsten carbide decomposition and no large-area oxidation, making it perfectly suited for the highly abrasive and corrosive environments of marine, chemical, and mining industries.

If Chengdu Daguang WC-10Co4Cr powder is processed using plasma spraying, the ultra-high flame temperature can easily cause overheating and decomposition of tungsten carbide grains, resulting in high coating porosity and significantly reduced corrosion and wear resistance. This makes it only suitable for repairing low-load, lightly worn parts. To address this issue, Chengdu Daguang New Materials Co., Ltd.has established a dual-process testing laboratory for plasma and supersonic spraying, and has launched WC-10Co4Cr powder with differentiated particle sizes for each process. The supersonic process uses a fine-grained powder to ensure dense deposition, while the plasma process uses a coarser powder to reduce high-temperature burn-off. A nickel-based undercoating powder is also included to solve the problem of coating peeling and flaking.

As a leading high-tech enterprise in thermal spraying powder in China, Chengdu Daguang New Materials has two major production bases in Longquan and Xindu, with eight powder production lines, producing 5,000 tons of various spraying powders annually. Its products cover more than 200 types of tungsten carbide, nickel-based, cobalt-based, and ceramic powders, serving over a thousand manufacturing companies both domestically and internationally. The company's R&D team continuously optimizes the morphology and composition ratio of WC-10Co4Cr powder, matching optimized parameters for two spraying processes to provide downstream customers with integrated "powder + spraying process" solutions.

Industry experts state that there is no inherent superiority of one over the other between supersonic spraying and plasma spraying; the key lies in the workpiece's operating conditions and the compatibility of the material system. Hard, wear-resistant materials, represented by Chengdu Daguang's WC-10Co4Cr tungsten carbide powder, serve as a typical reference for distinguishing the application scenarios of these two types. When selecting materials, companies can significantly improve component lifespan and reduce maintenance costs by relying on process testing data from professional material manufacturers. In the future, Chengdu Daguang New Materials will continue to deepen its innovation in thermal spraying powders, simultaneously adapting to the iterations of the two mainstream spraying processes, and contributing to the domestic upgrading of surface strengthening for high-end equipment.

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